Telephone Ringers: how & why

[David Lesher]

Years ago, I read an explanation of why telco ringers are what they are.
[Or ...were..., now that we are doomed to tweedlers...except @ my house
where the 2565 lives on forever...]

Yea, we know that they are typically 20hz, sinusoidal waveform,
~120VAC RMS atop 45VDC....

But... the WHY behind those decisions was illuminating. After all,
there's a fair chunk of change in that dual gong ringer's magnetic
design, etc...

The explanation had to do with the issue of coupling enough energy down
a twisted pair tens of thousands of feet long, with 2R series resistance
and Xc capacitive reactance shunting things.

I have no idea where I read this; it could have even been a Larry Lippman
post, but I don't find anything in a brief search.

Does anyone here recall something on this?

[ChairmanOfTheBored]

Post by David Lesher
The explanation had to do with the issue of coupling enough energy down
a twisted pair tens of thousands of feet long, with 2R series resistance
and Xc capacitive reactance shunting things.
I have no idea where I read this; it could have even been a Larry Lippman
post, but I don't find anything in a brief search.
Does anyone here recall something on this?

Sure, that's what it was about. That was also why all phones at one's
house had to be declared, and their "ringer equivalency number" and
ampere rating. Folks at the very end of a such a line didn't have much
juice left to actually actuate the ringer, which was an electro-magnet
pulling a flat plate against the end of the coil/pole combo, then
releasing it. The bell rang one tone on the pull, which required the
power, and ALWAYS would ring the other on release.

[T]

Post by ChairmanOfTheBored

Post by David Lesher
The explanation had to do with the issue of coupling enough energy down
a twisted pair tens of thousands of feet long, with 2R series resistance
and Xc capacitive reactance shunting things.
I have no idea where I read this; it could have even been a Larry Lippman
post, but I don't find anything in a brief search.
Does anyone here recall something on this?

Sure, that's what it was about. That was also why all phones at one's
house had to be declared, and their "ringer equivalency number" and
ampere rating. Folks at the very end of a such a line didn't have much
juice left to actually actuate the ringer, which was an electro-magnet
pulling a flat plate against the end of the coil/pole combo, then
releasing it. The bell rang one tone on the pull, which required the
power, and ALWAYS would ring the other on release.

And that very same 90VAC 20Hz ring signal meant that the first
electronic switching system deployed in Morris, IL need custom phones
with electronic ringer because the gas tubes couldn't handle the high
voltage necessary to pass ring. They overcame that with the Remendur
switches but it took time.

[Terry]

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]
Yea, we know that they are typically 20hz, sinusoidal waveform,
~120VAC RMS atop 45VDC....
But... the WHY behind those decisions was illuminating. After all,
there's a fair chunk of change in that dual gong ringer's magnetic
design, etc...
The explanation had to do with the issue of coupling enough energy down
a twisted pair tens of thousands of feet long, with 2R series resistance
and Xc capacitive reactance shunting things.
I have no idea where I read this; it could have even been a Larry Lippman
post, but I don't find anything in a brief search.
Does anyone here recall something on this?

The stuff I have always worked with was 48vdc and 90vac, and the 90vac was
not always sinusoidal, but close.

TerryS

[David Lesher]

Post by Terry
The stuff I have always worked with was 48vdc and 90vac, and the 90vac was
not always sinusoidal, but close.

Well, in theory 48V, [my typo..] but in reality above that in float, and
even more in equalize...

My SubCycle provides ~110Vrms unloaded....

[Charlie Edmondson]

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]
Yea, we know that they are typically 20hz, sinusoidal waveform,
~120VAC RMS atop 45VDC....
But... the WHY behind those decisions was illuminating. After all,
there's a fair chunk of change in that dual gong ringer's magnetic
design, etc...
The explanation had to do with the issue of coupling enough energy down
a twisted pair tens of thousands of feet long, with 2R series resistance
and Xc capacitive reactance shunting things.
I have no idea where I read this; it could have even been a Larry Lippman
post, but I don't find anything in a brief search.
Does anyone here recall something on this?

Also, remember, that there were several frequencies available for
ringing, to allow for party lines. Each home had a different frequency
ringer, so one could be distinguished from the other. In the CO, they
had to manually wire the correct ringing frequency to that line.

Charlie

[Don Bowey]

Post by Charlie Edmondson

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]
Yea, we know that they are typically 20hz, sinusoidal waveform,
~120VAC RMS atop 45VDC....
But... the WHY behind those decisions was illuminating. After all,
there's a fair chunk of change in that dual gong ringer's magnetic
design, etc...
The explanation had to do with the issue of coupling enough energy down
a twisted pair tens of thousands of feet long, with 2R series resistance
and Xc capacitive reactance shunting things.
I have no idea where I read this; it could have even been a Larry Lippman
post, but I don't find anything in a brief search.
Does anyone here recall something on this?

Also, remember, that there were several frequencies available for
ringing, to allow for party lines. Each home had a different frequency
ringer, so one could be distinguished from the other. In the CO, they
had to manually wire the correct ringing frequency to that line.
Charlie

Not all telcos used frequency selective ringers. Bell was, I believe, 20
Hz. I know United Tel, General Tel, and many smaller companies used FS
ringers.

[Charlie Edmondson]

Post by Don Bowey

Post by Charlie Edmondson

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]
Yea, we know that they are typically 20hz, sinusoidal waveform,
~120VAC RMS atop 45VDC....
But... the WHY behind those decisions was illuminating. After all,
there's a fair chunk of change in that dual gong ringer's magnetic
design, etc...
The explanation had to do with the issue of coupling enough energy down
a twisted pair tens of thousands of feet long, with 2R series resistance
and Xc capacitive reactance shunting things.
I have no idea where I read this; it could have even been a Larry Lippman
post, but I don't find anything in a brief search.
Does anyone here recall something on this?

Also, remember, that there were several frequencies available for
ringing, to allow for party lines. Each home had a different frequency
ringer, so one could be distinguished from the other. In the CO, they
had to manually wire the correct ringing frequency to that line.
Charlie

Not all telcos used frequency selective ringers. Bell was, I believe, 20
Hz. I know United Tel, General Tel, and many smaller companies used FS
ringers.

Well, since I was working for GTE at the time... 8-)

Charlie

[David Lesher]

Post by Charlie Edmondson
Also, remember, that there were several frequencies available for
ringing, to allow for party lines. Each home had a different frequency
ringer, so one could be distinguished from the other. In the CO, they
had to manually wire the correct ringing frequency to that line.

Not in Bell. They used tip party/ring party; and the gas tube bias
scheme.

GTE and independents used various frequency selective schemes.
There were at least 3.

This ties back to my original, unanswered, question. Straight line
ringers were not tuned. Yet they somehow resonated.....

[Charlie Edmondson]

Post by David Lesher

Post by Charlie Edmondson
Also, remember, that there were several frequencies available for
ringing, to allow for party lines. Each home had a different frequency
ringer, so one could be distinguished from the other. In the CO, they
had to manually wire the correct ringing frequency to that line.

Not in Bell. They used tip party/ring party; and the gas tube bias
scheme.
GTE and independents used various frequency selective schemes.
There were at least 3.
This ties back to my original, unanswered, question. Straight line
ringers were not tuned. Yet they somehow resonated.....

They are capacitively coupled to the line, so they alternated between
different directions due to the ringing frequency. They didn't have to
resonate at all...

charlie

[Terry]

Post by Charlie Edmondson

Post by David Lesher

Post by Charlie Edmondson
Also, remember, that there were several frequencies available for
ringing, to allow for party lines. Each home had a different frequency
ringer, so one could be distinguished from the other. In the CO, they
had to manually wire the correct ringing frequency to that line.

Not in Bell. They used tip party/ring party; and the gas tube bias
scheme. GTE and independents used various frequency selective schemes.
There were at least 3. This ties back to my original, unanswered,
question. Straight line
ringers were not tuned. Yet they somehow resonated.....

They are capacitively coupled to the line, so they alternated between
different directions due to the ringing frequency. They didn't have to
resonate at all...
charlie

But the impedences of the ringer are optimized for 20hz I bet. And why 20hz
? I don't remember.

TerryS

[Rich Grise]

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]
Yea, we know that they are typically 20hz, sinusoidal waveform,
~120VAC RMS atop 45VDC....
But... the WHY behind those decisions was illuminating. After all,
there's a fair chunk of change in that dual gong ringer's magnetic
design, etc...
The explanation had to do with the issue of coupling enough energy down
a twisted pair tens of thousands of feet long, with 2R series resistance
and Xc capacitive reactance shunting things.
I have no idea where I read this; it could have even been a Larry Lippman
post, but I don't find anything in a brief search.
Does anyone here recall something on this?

I once read something, not about the electric part, but that the bell
frequencies, and clapper rate, were specifically chosen to be "an
'impatient' sound", i.e., as annoying a sound as they could make
with the technology of the day.

Cheers!
Rich

[John Agosta]

Post by Rich Grise

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]
Yea, we know that they are typically 20hz, sinusoidal waveform,
~120VAC RMS atop 45VDC....
But... the WHY behind those decisions was illuminating. After all,
there's a fair chunk of change in that dual gong ringer's magnetic
design, etc...
The explanation had to do with the issue of coupling enough energy down
a twisted pair tens of thousands of feet long, with 2R series resistance
and Xc capacitive reactance shunting things.
I have no idea where I read this; it could have even been a Larry Lippman
post, but I don't find anything in a brief search.
Does anyone here recall something on this?

I once read something, not about the electric part, but that the bell
frequencies, and clapper rate, were specifically chosen to be "an
'impatient' sound", i.e., as annoying a sound as they could make
with the technology of the day.

Then they should have had it play country music.

;-)

Post by Rich Grise
Cheers!
Rich

Yes, Cheers !

[Tom2000]

On Tue, 21 Aug 2007 23:04:59 -0500, "John Agosta"

Post by John Agosta

Post by Rich Grise
I once read something, not about the electric part, but that the bell
frequencies, and clapper rate, were specifically chosen to be "an
'impatient' sound", i.e., as annoying a sound as they could make
with the technology of the day.

An old-time telephone engineer once told me the same thing. Might
be some truth in it.

Post by John Agosta
Then they should have had it play country music.

LOL! Hear, hear!

Tom

[William Pechter]

Post by Tom2000
On Tue, 21 Aug 2007 23:04:59 -0500, "John Agosta"

Post by John Agosta

Post by Rich Grise
I once read something, not about the electric part, but that the bell
frequencies, and clapper rate, were specifically chosen to be "an
'impatient' sound", i.e., as annoying a sound as they could make
with the technology of the day.

An old-time telephone engineer once told me the same thing. Might
be some truth in it.

Post by John Agosta
Then they should have had it play country music.

LOL! Hear, hear!
Tom

Nah... should have been VT52 terminal bell... er Buzzers.

Bill

[Floyd L. Davidson]

Post by William Pechter

Post by Tom2000
An old-time telephone engineer once told me the same thing. Might
be some truth in it.

Post by John Agosta
Then they should have had it play country music.

LOL! Hear, hear!
Tom

Nah... should have been VT52 terminal bell... er Buzzers.

Besides, I thought that *was* country music.

[Michael A. Terrell]

Post by Floyd L. Davidson

Post by William Pechter

Post by Tom2000
An old-time telephone engineer once told me the same thing. Might
be some truth in it.

Post by John Agosta
Then they should have had it play country music.

LOL! Hear, hear!
Tom

Nah... should have been VT52 terminal bell... er Buzzers.

Besides, I thought that *was* country music.

That shows what little you know about music.

[Curtis R Anderson]

Post by William Pechter

Post by Tom2000
On Tue, 21 Aug 2007 23:04:59 -0500, "John Agosta"

Post by John Agosta

Post by Rich Grise
I once read something, not about the electric part, but that the bell
frequencies, and clapper rate, were specifically chosen to be "an
'impatient' sound", i.e., as annoying a sound as they could make
with the technology of the day.

An old-time telephone engineer once told me the same thing. Might
be some truth in it.

Post by John Agosta
Then they should have had it play country music.

LOL! Hear, hear!
Tom

Nah... should have been VT52 terminal bell... er Buzzers.

I heard those were annoying. The Volker-Craig VC404 had an annoying beep
as well.

[Gary Tait]

Post by Curtis R Anderson

Post by William Pechter
Nah... should have been VT52 terminal bell... er Buzzers.

I heard those were annoying. The Volker-Craig VC404 had an annoying beep
as well.

I don't know if that was one I had, but I had one that used a sonalert for
a "bell". It had a screwed on composite CRT monitor (Electrohome chassis),
I later used on a PC-XT with a CGA card with the dual RCA outputs (on the
monochrome jack, it worked rather well), and the Y output on a C-64.

Inside the case was about 4 cards on a bus (one with a gold and ceramic
UART, and other with memory chips in rund can ICs), and a keyboard sticking
out. I also had a different VC terminal, which had the keboard seprate on a
ribbon, and the terminal works on two card on the right, and a CRT card,
with the PSU and a speaker on the mainboard. I reworked that to be a
monitor for another PC-XT system with a Hercules card.

[T]

Post by Gary Tait

Post by Curtis R Anderson

Post by William Pechter
Nah... should have been VT52 terminal bell... er Buzzers.

I heard those were annoying. The Volker-Craig VC404 had an annoying beep
as well.

I don't know if that was one I had, but I had one that used a sonalert for
a "bell". It had a screwed on composite CRT monitor (Electrohome chassis),
I later used on a PC-XT with a CGA card with the dual RCA outputs (on the
monochrome jack, it worked rather well), and the Y output on a C-64.
Inside the case was about 4 cards on a bus (one with a gold and ceramic
UART, and other with memory chips in rund can ICs), and a keyboard sticking
out. I also had a different VC terminal, which had the keboard seprate on a
ribbon, and the terminal works on two card on the right, and a CRT card,
with the PSU and a speaker on the mainboard. I reworked that to be a
monitor for another PC-XT system with a Hercules card.

Thankfully all my experiences were with real VT100 and DG D416
terminals.

[Winfield]

Post by David Lesher
Years ago, I read an explanation of why telco ringers are
what they are. Yea, we know that they are typically 20hz,
sinusoidal waveform, ~120VAC RMS atop 45VDC....
But... the WHY ...

The irony is that actual ringing-clapper phones are not
in service anymore. Modern electronic phone apparatus,
whether a telco, a PABX, or a small LinkSys VoIP module,
has to create this ancient high-voltage ringing signal,
and then a modern electronic phone has to respond to it,
by creating a logic signal or whatever, and thereafter
making its own ringing indication. How awkward.

The Institute's PABX, the second one we've purchased since
I arrived 19 years ago, has started acting up - four or
five of the lines have weak or defective ringing outputs,
so those phones don't ring, or do so unreliably. The PABX
uses 8-line cards, each one apparently with its own ringing
generator. But replacing what appeared to be one defective
card only partially solved the problem. We've just placed
a new PABX on order, but it won't be installed for a month
or so, and so we may need to make emergency repairs to the
old one. No schematics are available, of course. But at
least the circuits use ordinary components, SFAICT, from a
quick look at the defective card last night. How awkward.

The putative ringing-generator circuit sports a classic
'3842 PWM chip. I don't know if that's awkward or not.
I say that, because it doesn't appear to be simply used
as an ordinary high-voltage DC generator, because there
are no other power parts, as would be needed to make a
class AB HV amplifier, etc. There is one transformer.

[Grant Edwards]

Post by Winfield

Post by David Lesher
Years ago, I read an explanation of why telco ringers are
what they are. Yea, we know that they are typically 20hz,
sinusoidal waveform, ~120VAC RMS atop 45VDC....
But... the WHY ...

The irony is that actual ringing-clapper phones are not
in service anymore.

Sure they are. I've got one plugged in at home, and there's
one here at work as well. OK, the on at work is only "in
service" if the PBX is powered down, but it's there...

[Gary Tait]

Post by Winfield
The irony is that actual ringing-clapper phones are not
in service anymore. Modern electronic phone apparatus,
whether a telco, a PABX, or a small LinkSys VoIP module,
has to create this ancient high-voltage ringing signal,
and then a modern electronic phone has to respond to it,
by creating a logic signal or whatever, and thereafter
making its own ringing indication. How awkward.

Its all because they have to be backwards compatible to the old phones.
The not-so newer phones were made to work alongside onlt mechancial ringer
phones. Ihave here some early 90s phones that could have been used
alongside the old 500 set we had.

[T]

Post by Winfield

Post by David Lesher
Years ago, I read an explanation of why telco ringers are
what they are. Yea, we know that they are typically 20hz,
sinusoidal waveform, ~120VAC RMS atop 45VDC....
But... the WHY ...

The irony is that actual ringing-clapper phones are not
in service anymore. Modern electronic phone apparatus,
whether a telco, a PABX, or a small LinkSys VoIP module,
has to create this ancient high-voltage ringing signal,
and then a modern electronic phone has to respond to it,
by creating a logic signal or whatever, and thereafter
making its own ringing indication. How awkward.
The Institute's PABX, the second one we've purchased since
I arrived 19 years ago, has started acting up - four or
five of the lines have weak or defective ringing outputs,
so those phones don't ring, or do so unreliably. The PABX
uses 8-line cards, each one apparently with its own ringing
generator. But replacing what appeared to be one defective
card only partially solved the problem. We've just placed
a new PABX on order, but it won't be installed for a month
or so, and so we may need to make emergency repairs to the
old one. No schematics are available, of course. But at
least the circuits use ordinary components, SFAICT, from a
quick look at the defective card last night. How awkward.
The putative ringing-generator circuit sports a classic
'3842 PWM chip. I don't know if that's awkward or not.
I say that, because it doesn't appear to be simply used
as an ordinary high-voltage DC generator, because there
are no other power parts, as would be needed to make a
class AB HV amplifier, etc. There is one transformer.

I've got about fifty analog ports available on my Prologix so they do
push 90VAC/20Hz down the line for ring. If you look at the cards you'll
see they use a relay to switch between the talk path and ring current.

[Hal Murray]

Post by Winfield
The irony is that actual ringing-clapper phones are not
in service anymore.

Speak for yourself.

Mine has a sticker on the bottom that says says:
BELL SYSTEM PROPERTY NOT FOR SALE
and another that says:
Sold by: Pacific Telephone
Jan 09 1983

It has a dial too.

[h***@bbs.cpcn.com]

Post by Winfield
The irony is that actual ringing-clapper phones are not
in service anymore.

As others pointed out, plenty of telephones with mechanical readers
are in service. My office uses literally hundreds of plain vanilla
2500 sets.

Another factor in signalling is the length of the local loop. Several
people mentioned PBXs, but the requirements of loops in a PBX are
usually much easier than that of a central office (per the Bell System
history 1925-1975).

[T]

Post by h***@bbs.cpcn.com

Post by Winfield
The irony is that actual ringing-clapper phones are not
in service anymore.

As others pointed out, plenty of telephones with mechanical readers
are in service. My office uses literally hundreds of plain vanilla
2500 sets.
Another factor in signalling is the length of the local loop. Several
people mentioned PBXs, but the requirements of loops in a PBX are
usually much easier than that of a central office (per the Bell System
history 1925-1975).

Our office is mostly 6480D+'s, followed by 7406D and D+'s, and a few
8410D's.

No analog sets at all.

[h***@bbs.cpcn.com]

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]

In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer. To power the ringer, the
subscriber had a hand crank. I believe originally the frequency was
16 Hz, then later to 20 Hz. These were known as local battery
systems. The subscriber's telephone set had batteries in it. The
advtg of these systems was that worked well on lousy loops, either
very long ones or ones made of poor conductors (like fence posts).

On today's common battery systems, where the talking current is
supplied by the phone company, the ringer must be AC to be separate
and cut out, via the capacitor, so it won't shunt the line and appear
off hook. (Others can explain this better.)

In the old the days the Bell System knew how many extensions a
subscriber how since it provided them. I could ensure adequate ringer
power was available. Very few people had more than five extensions on
a single line.

But later people no longer had to rent their phones and could buy
them. A way was needed to avoid overloading the line, so a "ringer
equivalence" was set up. The plain Bell System 500 set was defined as
1.0 . As it turned out, most newer sets had a lower rating, my
Comdial 2500 with a mechanical ringer is 0.8, electronic ringers are
even less.

Would anyone know what the ringer equivalence be of older phones, such
as a 300 set or the Bell Chime?

I don't know if this system is used on all-new PBXs that have digital
phones, perhaps they use a different signalling technique altogether.
Obviously VOIP isn't shooting 20Hz 90VAC over the Internet.


Someone mentioned Morris IL, yes, they had to develop a low powered
tone ringer. But it didn't work out very well and was not continued.
ESS was developed to handle standard ringing. How it's done today
with digital switches I don't know.

[Richard Henry]

Post by h***@bbs.cpcn.com

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]

In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer. To power the ringer, the
subscriber had a hand crank. I believe originally the frequency was
16 Hz, then later to 20 Hz. These were known as local battery
systems. The subscriber's telephone set had batteries in it. The
advtg of these systems was that worked well on lousy loops, either
very long ones or ones made of poor conductors (like fence posts).
On today's common battery systems, where the talking current is
supplied by the phone company, the ringer must be AC to be separate
and cut out, via the capacitor, so it won't shunt the line and appear
off hook. (Others can explain this better.)
In the old the days the Bell System knew how many extensions a
subscriber how since it provided them. I could ensure adequate ringer
power was available. Very few people had more than five extensions on
a single line.
But later people no longer had to rent their phones and could buy
them. A way was needed to avoid overloading the line, so a "ringer
equivalence" was set up. The plain Bell System 500 set was defined as
1.0 . As it turned out, most newer sets had a lower rating, my
Comdial 2500 with a mechanical ringer is 0.8, electronic ringers are
even less.
Would anyone know what the ringer equivalence be of older phones, such
as a 300 set or the Bell Chime?
I don't know if this system is used on all-new PBXs that have digital
phones, perhaps they use a different signalling technique altogether.
Obviously VOIP isn't shooting 20Hz 90VAC over the Internet.
Someone mentioned Morris IL, yes, they had to develop a low powered
tone ringer. But it didn't work out very well and was not continued.
ESS was developed to handle standard ringing. How it's done today
with digital switches I don't know.

"Fence posts"?

[Michael A. Terrell]

Post by Richard Henry

Post by h***@bbs.cpcn.com

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]

In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer. To power the ringer, the
subscriber had a hand crank. I believe originally the frequency was
16 Hz, then later to 20 Hz. These were known as local battery
systems. The subscriber's telephone set had batteries in it. The
advtg of these systems was that worked well on lousy loops, either
very long ones or ones made of poor conductors (like fence posts).
On today's common battery systems, where the talking current is
supplied by the phone company, the ringer must be AC to be separate
and cut out, via the capacitor, so it won't shunt the line and appear
off hook. (Others can explain this better.)
In the old the days the Bell System knew how many extensions a
subscriber how since it provided them. I could ensure adequate ringer
power was available. Very few people had more than five extensions on
a single line.
But later people no longer had to rent their phones and could buy
them. A way was needed to avoid overloading the line, so a "ringer
equivalence" was set up. The plain Bell System 500 set was defined as
1.0 . As it turned out, most newer sets had a lower rating, my
Comdial 2500 with a mechanical ringer is 0.8, electronic ringers are
even less.
Would anyone know what the ringer equivalence be of older phones, such
as a 300 set or the Bell Chime?
I don't know if this system is used on all-new PBXs that have digital
phones, perhaps they use a different signalling technique altogether.
Obviously VOIP isn't shooting 20Hz 90VAC over the Internet.
Someone mentioned Morris IL, yes, they had to develop a low powered
tone ringer. But it didn't work out very well and was not continued.
ESS was developed to handle standard ringing. How it's done today
with digital switches I don't know.

"Fence posts"?

Sure! The used those 1.5 billion volt batteries to overcome the high
resistance.

[Grant Edwards]

Post by Michael A. Terrell

Post by Richard Henry

Post by h***@bbs.cpcn.com
In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer. To power the ringer, the
subscriber had a hand crank. I believe originally the frequency was
16 Hz, then later to 20 Hz. These were known as local battery
systems. The subscriber's telephone set had batteries in it. The
advtg of these systems was that worked well on lousy loops, either
very long ones or ones made of poor conductors (like fence posts).

"Fence posts"?

Sure! The used those 1.5 billion volt batteries to overcome
the high resistance.

The metal fenceposts actually have a fairly low resistance.
Unfortunately they're also pretty much grounded...

[David Lesher]

Post by h***@bbs.cpcn.com

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]

In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer.

....


This is the 6th grade Phun with Science level explanation; one you might
see in what I called "Popular YuckTronics" magazine.

If you look at my origianl query, you can see I was addressing the far
less obvious issue of getting enough power down the far-from-ideal line
to run the ringers. THAT is what I still seek insight into....

[and why I x-posted to s.e.d...]

[Rich Grise]

Post by David Lesher

Post by h***@bbs.cpcn.com

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]

In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer.

This is the 6th grade Phun with Science level explanation; one you might
see in what I called "Popular YuckTronics" magazine.
If you look at my origianl query, you can see I was addressing the far
less obvious issue of getting enough power down the far-from-ideal line
to run the ringers. THAT is what I still seek insight into....

You _push_ it through. You provide enough voltage at the source end
such that the resulting current is equal to the current rating of
the ringer coil(s). (or whatever it is you're signaling.)

Hope This Helps!
Rich

[Don Bowey]

Post by David Lesher

Post by h***@bbs.cpcn.com

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]

In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer.

....
This is the 6th grade Phun with Science level explanation; one you might
see in what I called "Popular YuckTronics" magazine.
If you look at my origianl query, you can see I was addressing the far
less obvious issue of getting enough power down the far-from-ideal line
to run the ringers. THAT is what I still seek insight into....
[and why I x-posted to s.e.d...]

I haven't read the entire thread so this may not be new to you.

Without knowing more about the particular ringer you have in mind, I can
only generalize.

FCC requirements, and those of the Standard, ANSI T1.401-200? prevail and
provide some insight. My T1.401 copy was issued in 1993, but likely still
valid for this subject.

When a Central Office puts an Alert (the ring signal) on your phone line, it
has both a DC and an AC component.

The DC is typically 52 Volts, but may be higher or lower, but in any case it
has nothing to do with ringing your bell. It is used to determine if your
phone has gone off-hook indicating you answered your phone. This is really a
safety feature so you don't get that loud ring in your ear.

The AC ringing voltage, nominally 105 VAC, rings the bell. At the time my
copy of the Standard was issued there were 13 possible ringers, itemized by
their intended use frequency (between 16.6 Hz. and 66.6 Hz.), still in use
in the USA.

This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.

I hope this helps.

Don

[Bob]

[snip]

Post by Don Bowey
This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.
I hope this helps.
Don

If I recall correctly, a REN=1 has an effective impedance of about 8,000
ohms which results in about 1W of power. This is what we used to estimate
the ring generator requirements for the PBX that I used to work on.

I'll see if I can find the Bell Pub that gives the formula for calculating
the ringer equivalence number, but I'm pretty sure that 1W for a REN of 1 is
about right.

Bob

[Bob]

Post by Bob
[snip]

Post by Don Bowey
This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.
I hope this helps.
Don

If I recall correctly, a REN=1 has an effective impedance of about 8,000
ohms which results in about 1W of power. This is what we used to estimate
the ring generator requirements for the PBX that I used to work on.
I'll see if I can find the Bell Pub that gives the formula for calculating
the ringer equivalence number, but I'm pretty sure that 1W for a REN of 1
is about right.
Bob

The REN definition is in FCC Title 47 part 68 (aka FCC part 68). Look at the
section "Ringer Equivalence Definition" on page 336.

http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/cfr/1999/47cfr68.pdf

For a 20Hz ringer, the minimum ac impedance for REN=1 (what they call "N")
for a loop start line is 7000ohms.

The 3mA you were referring to is the maximum dc current that can flow during
ringing, but the ac current is much higher.

Bob

[Don Bowey]

On 8/26/07 8:08 AM, in article

Post by Bob

Post by Bob
[snip]

Post by Don Bowey
This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.
I hope this helps.
Don

If I recall correctly, a REN=1 has an effective impedance of about 8,000
ohms which results in about 1W of power. This is what we used to estimate
the ring generator requirements for the PBX that I used to work on.
I'll see if I can find the Bell Pub that gives the formula for calculating
the ringer equivalence number, but I'm pretty sure that 1W for a REN of 1
is about right.
Bob

The REN definition is in FCC Title 47 part 68 (aka FCC part 68). Look at the
section "Ringer Equivalence Definition" on page 336.
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/cfr/1999/47cfr68.p
df
For a 20Hz ringer, the minimum ac impedance for REN=1 (what they call "N")
for a loop start line is 7000ohms.
The 3mA you were referring to is the maximum dc current that can flow during
ringing, but the ac current is much higher.
Bob

You're right, thanks. I see where I went astray. My eyes aren't up to
reading that hard copy fine print any more.

So if we assume 130V of ring voltage we're looking at about 19 mA of 20 Hz.
current.

Sorry for the confusion on my part.

[David Lesher]

Post by Bob
The REN definition is in FCC Title 47 part 68 (aka FCC part 68). Look at the
section "Ringer Equivalence Definition" on page 336.
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/cfr/1999/47cfr68.pdf
For a 20Hz ringer, the minimum ac impedance for REN=1 (what they call "N")
for a loop start line is 7000ohms.

So if you have 3 ringers in parallel on a 5+ mile [26Kfeet] loop, you
have a damn good voltage divider. Now, take ten miles.

I seem to recall Al saying the longest loop found in a survey was
100Kft. Gulp.

[Bob]

Post by David Lesher

Post by Bob
The REN definition is in FCC Title 47 part 68 (aka FCC part 68). Look at the
section "Ringer Equivalence Definition" on page 336.
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/cfr/1999/47cfr68.pdf
For a 20Hz ringer, the minimum ac impedance for REN=1 (what they call "N")
for a loop start line is 7000ohms.

So if you have 3 ringers in parallel on a 5+ mile [26Kfeet] loop, you
have a damn good voltage divider. Now, take ten miles.
I seem to recall Al saying the longest loop found in a survey was
100Kft. Gulp.

Yeah, according to FCC Part 68, the minimum total ac ringer impedance for a
loop start (POTS) line is 1400ohms. I seem to recall that 1800ohms was the
max dcr for a loop. So, yes, that's a nice voltage divider.

Part 68 also says that the minimum ring gen supply voltage might be 40Vrms
(I remember 65Vrms from BellPub 48002 - but that's for PBXs). If the loop is
1800ohms and the ringer load (REN=5) is 1400ohms, that only leaves 17.5Vrms
for the ringers worst case. I can't imagine ringers working down to this low
of a voltage, so I would assume that on these long loops the telcos would
limit the total REN to something much smaller than 5.

Thank goodness ISDN became so popular and replaced most of our POTS lines.
;-D

Bob

[David Lesher]

Post by Bob
Thank goodness ISDN became so popular and replaced most of our POTS lines.
;-D

You laugh but I talked a friend into ISDN. He's 41Kft out but it
works 99% of the time, and is many dB quieter than his POTS. It was
...disquieting.. to call him from my 7507 as there would zero line noise
and during pauses in conversation, you'd often think the circuit was dead...

[David Lesher]

Post by Don Bowey
I haven't read the entire thread so this may not be new to you.

...

Post by Don Bowey
This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.

My query stems from the dim neurons of my brane. It was about the issue
of getting enough power down that long R-C filter [...called the local
loop...] to power the multiple ringers in a house.

It had nothing to do with saving CO ring suppy power. Before
SubCycle's became SOP, She used to have big honking 48VDC->120V 20Hz
motor-generators in the larger CO's and various uglyness in smaller
ones. Not even a anal beancounter could find that load midst a large
panel or step installation.

There was some very clever aspect of the whole design of the ringer
magnetics that solved the issue. THAT's what I'm interested in learning
about.

[Terry]

Post by David Lesher

Post by Don Bowey
I haven't read the entire thread so this may not be new to you.

...

Post by Don Bowey
This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.

My query stems from the dim neurons of my brane. It was about the issue
of getting enough power down that long R-C filter [...called the local
loop...] to power the multiple ringers in a house.
It had nothing to do with saving CO ring suppy power. Before
SubCycle's became SOP, She used to have big honking 48VDC->120V 20Hz
motor-generators in the larger CO's and various uglyness in smaller
ones. Not even a anal beancounter could find that load midst a large
panel or step installation.
There was some very clever aspect of the whole design of the ringer
magnetics that solved the issue. THAT's what I'm interested in learning
about.

Well, the standard bell must have been tuned to 20hz, thats just good power
economics, and it would not respond to transients, or 60hz pickup. With a
standard 2 on 4 off cycle, I bet that one third of the bells all rang at the
same time. Just to keep the load on the generator constant. Note that a
party line would have bells tuned to different frequencies.

TerryS

[David Lesher]

Post by Terry

Post by David Lesher
There was some very clever aspect of the whole design of the ringer
magnetics that solved the issue. THAT's what I'm interested in learning
about.

Well, the standard bell must have been tuned to 20hz, thats just good power
economics, and it would not respond to transients, or 60hz pickup. With a
standard 2 on 4 off cycle, I bet that one third of the bells all rang at the
same time. Just to keep the load on the generator constant. Note that a
party line would have bells tuned to different frequencies.

Nope, the standard ringer is not tuned to 20 Hz. It responds {at least} to 30 hz and
other frequencies, can't recall how low...

Again, generator load is not relevant to my question...

And BTW, Ma never used frequency selective ringing; only independents did.

(Another poster asked "Why 20 hz?" and I echo that question...)

[Floyd L. Davidson]

Post by David Lesher

Post by Terry

Post by David Lesher
There was some very clever aspect of the whole design of the ringer
magnetics that solved the issue. THAT's what I'm interested in learning
about.

Well, the standard bell must have been tuned to 20hz, thats just good power
economics, and it would not respond to transients, or 60hz pickup. With a
standard 2 on 4 off cycle, I bet that one third of the bells all rang at the
same time. Just to keep the load on the generator constant. Note that a
party line would have bells tuned to different frequencies.

Nope, the standard ringer is not tuned to 20 Hz. It responds {at least} to 30 hz and
other frequencies, can't recall how low...

Including 60 Hz.

Post by David Lesher
Again, generator load is not relevant to my question...

That Big Honking motor generator, or whatever it was you
called it, not only generated a continuous supply of 20
Hz ring voltage, it also (as I'm sure you well know,
David) drove an "interrupter", and various different
lines that were ringing at any given time would be
supplied by different contacts on the interrupter, which
did tend to equalize the load cycle.

Post by David Lesher
And BTW, Ma never used frequency selective ringing; only independents did.
(Another poster asked "Why 20 hz?" and I echo that question...)

I don't remember ever seeing anything definitive, but
what your original post described did in fact sound like
Larry Lippman or maybe Al Varney. It used to be really
interesting reading what they had to say...

My understanding is that the 20 Hz ring current
originated with the hand cranked magneto system. It was
simply a case that hand cranking generated about 20 Hz
(and obviously was not necessarily 20 Hz, hence a
frequency selective ringer could not possibly have been
used). They generated 50-70 VAC.

Larger switchboards would have had a motorized ring
generator, even when magneto phones where in use. That
of course became standard with common-battery and
automatic switching systems.

But there are some other odd things that might be what
you remember. Long distance lines and telegraph lines
required some special consideration. 20Hz doesn't
travel well over a long line, does not survive any sort
of a repeater.

There originally had been 135 Hz ring systems between
offices. Those also do not travel well, but when used
with a repeatered system, every other segment could be
20 Hz and the ones in between 135 Hz. In that way it
was possible to build a repeater that could pass
signaling.

Carrier systems made that unworkable too. The first
signaling to replace 20 Hz and 135 Hz for carrier
systems was 1000 Hz signaling. That was followed by a
number of things, mainly selective signaling (SS-1) that
used two tones, and eventually the well known 2600 Hz
(and less known 2400 Hz) Single Frequency (SF) system.

The ringers for party line use were interesting too.
A standard ringer could be any of 1) across tip and ring
(single party line) or 2) from tip to ground or 3) from
ring to ground. The last two obviously allow two ringers
on one line, for two party service.

But a "biased" ringer was also used. It had a spring
that pulled it to one side, and would respond to AC, but
with "pulsed DC" (for example a line with 52 VDC loop
voltage on it and superimposed AC ring current) it would
ring only if the polarity of the line was correct. A
two party line would use two of them, and at the CO the
line cards would be connected to the same line, but one
of them would be reversed tip and ring, and in the field
the phones would be wired with the same turnover. The
two systems could be combined to provide 4 party
service, with two biased ringers across the line and one
each from tip and ring to ground.

[Justa Lurker]

Post by Floyd L. Davidson
The ringers for party line use were interesting too.
A standard ringer could be any of 1) across tip and ring
(single party line) or 2) from tip to ground or 3) from
ring to ground.

When a subscriber instrument on a multiple-party line was installed at a
customer's location, how did the craftsman get a good electrical
connection to ground so that the ringer would operate properly ? Would
they clamp onto a cold-water pipe coming in from the street, drive a
ground rod, tap into the ground connection on the electrical panel, ...?
For that matter, wasn't an electrical ground required at each
subscriber location [single or multiple party] for the line protector ?

[Floyd L. Davidson]

Post by Justa Lurker

Post by Floyd L. Davidson
The ringers for party line use were interesting too.
A standard ringer could be any of 1) across tip and ring
(single party line) or 2) from tip to ground or 3) from
ring to ground.

When a subscriber instrument on a multiple-party line
was installed at a customer's location, how did the
craftsman get a good electrical connection to ground so
that the ringer would operate properly ? Would they
clamp onto a cold-water pipe coming in from the street,
drive a ground rod, tap into the ground connection on
the electrical panel, ...? For that matter, wasn't an
electrical ground required at each subscriber location
[single or multiple party] for the line protector ?

They were (are) required to drive a ground rod. The
difference now is that only two wires, tip and ring, are
required to be extended to the actual telephone set,
where as with a party line phone using that method there
had to be 3 wires, with the ground also going to the
telset.

[David Lesher]

Post by Floyd L. Davidson

Post by Justa Lurker
When a subscriber instrument on a multiple-party line
was installed at a customer's location, how did the
craftsman get a good electrical connection to ground so
that the ringer would operate properly ? Would they
clamp onto a cold-water pipe coming in from the street,
drive a ground rod, tap into the ground connection on
the electrical panel, ...? For that matter, wasn't an
electrical ground required at each subscriber location
[single or multiple party] for the line protector ?

They were (are) required to drive a ground rod. The
difference now is that only two wires, tip and ring, are
required to be extended to the actual telephone set,
where as with a party line phone using that method there
had to be 3 wires, with the ground also going to the
telset.

Well, sorta.... They started out that way. They drove a ground, and
tagged it.

Worked fine for years, until some idiots started putting transistors out
there in the world. And even then, as long as the phone sat on insulated
feet... But take anything line-powered, such as the 1A1/1A2 keysystem.
They'd have TWO grounds, one from the rod, another from the utility
plug. Ooops..

So Ma had a big campaign preaching MGN -- Multi-ground neutral aka the
power meter ground. All protectors went to the power meter/utility
grounding point. They even had a little film every installer got to watch
in class, and a modified BSP.

And re: 4 party ringing; Bell used gas tubes. One party had one in
series with the ringer, the other across it, I think. To ring the
first you put the ring voltage atop a ??100V+ bias, to excite those
tubes into conduction.

Then they repeated it on the other [tip vs ring] side for the other
2 parties.

[T]

Post by David Lesher

Post by Floyd L. Davidson

Post by Justa Lurker
When a subscriber instrument on a multiple-party line
was installed at a customer's location, how did the
craftsman get a good electrical connection to ground so
that the ringer would operate properly ? Would they
clamp onto a cold-water pipe coming in from the street,
drive a ground rod, tap into the ground connection on
the electrical panel, ...? For that matter, wasn't an
electrical ground required at each subscriber location
[single or multiple party] for the line protector ?

They were (are) required to drive a ground rod. The
difference now is that only two wires, tip and ring, are
required to be extended to the actual telephone set,
where as with a party line phone using that method there
had to be 3 wires, with the ground also going to the
telset.

Well, sorta.... They started out that way. They drove a ground, and
tagged it.
Worked fine for years, until some idiots started putting transistors out
there in the world. And even then, as long as the phone sat on insulated
feet... But take anything line-powered, such as the 1A1/1A2 keysystem.
They'd have TWO grounds, one from the rod, another from the utility
plug. Ooops..
So Ma had a big campaign preaching MGN -- Multi-ground neutral aka the
power meter ground. All protectors went to the power meter/utility
grounding point. They even had a little film every installer got to watch
in class, and a modified BSP.
And re: 4 party ringing; Bell used gas tubes. One party had one in
series with the ringer, the other across it, I think. To ring the
first you put the ring voltage atop a ??100V+ bias, to excite those
tubes into conduction.
Then they repeated it on the other [tip vs ring] side for the other
2 parties.

Bell loved gas tubes. They even had front ends for Crossbar switches
that were gas tubes and the Morris, IL ESS trial used gas tubes excited
by fluorescent bulbs.

[Richard Henry]

Post by Floyd L. Davidson

Post by David Lesher

Post by Terry

Post by David Lesher
There was some very clever aspect of the whole design of the ringer
magnetics that solved the issue. THAT's what I'm interested in learning
about.

Well, the standard bell must have been tuned to 20hz, thats just good power
economics, and it would not respond to transients, or 60hz pickup. With a
standard 2 on 4 off cycle, I bet that one third of the bells all rang at the
same time. Just to keep the load on the generator constant. Note that a
party line would have bells tuned to different frequencies.

Nope, the standard ringer is not tuned to 20 Hz. It responds {at least} to 30 hz and
other frequencies, can't recall how low...

Including 60 Hz.

Post by David Lesher
Again, generator load is not relevant to my question...

That Big Honking motor generator, or whatever it was you
called it, not only generated a continuous supply of 20
Hz ring voltage, it also (as I'm sure you well know,
David) drove an "interrupter", and various different
lines that were ringing at any given time would be
supplied by different contacts on the interrupter, which
did tend to equalize the load cycle.

Post by David Lesher
And BTW, Ma never used frequency selective ringing; only independents did.
(Another poster asked "Why 20 hz?" and I echo that question...)

I don't remember ever seeing anything definitive, but
what your original post described did in fact sound like
Larry Lippman or maybe Al Varney. It used to be really
interesting reading what they had to say...
My understanding is that the 20 Hz ring current
originated with the hand cranked magneto system. It was
simply a case that hand cranking generated about 20 Hz
(and obviously was not necessarily 20 Hz, hence a
frequency selective ringer could not possibly have been
used). They generated 50-70 VAC.
Larger switchboards would have had a motorized ring
generator, even when magneto phones where in use. That
of course became standard with common-battery and
automatic switching systems.
But there are some other odd things that might be what
you remember. Long distance lines and telegraph lines
required some special consideration. 20Hz doesn't
travel well over a long line, does not survive any sort
of a repeater.
There originally had been 135 Hz ring systems between
offices. Those also do not travel well, but when used
with a repeatered system, every other segment could be
20 Hz and the ones in between 135 Hz. In that way it
was possible to build a repeater that could pass
signaling.
Carrier systems made that unworkable too. The first
signaling to replace 20 Hz and 135 Hz for carrier
systems was 1000 Hz signaling. That was followed by a
number of things, mainly selective signaling (SS-1) that
used two tones, and eventually the well known 2600 Hz
(and less known 2400 Hz) Single Frequency (SF) system.
The ringers for party line use were interesting too.
A standard ringer could be any of 1) across tip and ring
(single party line) or 2) from tip to ground or 3) from
ring to ground. The last two obviously allow two ringers
on one line, for two party service.
But a "biased" ringer was also used. It had a spring
that pulled it to one side, and would respond to AC, but
with "pulsed DC" (for example a line with 52 VDC loop
voltage on it and superimposed AC ring current) it would
ring only if the polarity of the line was correct. A
two party line would use two of them, and at the CO the
line cards would be connected to the same line, but one
of them would be reversed tip and ring, and in the field
the phones would be wired with the same turnover. The
two systems could be combined to provide 4 party
service, with two biased ringers across the line and one
each from tip and ring to ground.

The party line system installed in my grandparents' farm just rang
every phone in the valley, but with coded rings (one long, two short,
etc).

[Floyd L. Davidson]

...

Post by Richard Henry

Post by Floyd L. Davidson
But a "biased" ringer was also used. It had a spring
that pulled it to one side, and would respond to AC, but
with "pulsed DC" (for example a line with 52 VDC loop
voltage on it and superimposed AC ring current) it would
ring only if the polarity of the line was correct. A
two party line would use two of them, and at the CO the
line cards would be connected to the same line, but one
of them would be reversed tip and ring, and in the field
the phones would be wired with the same turnover. The
two systems could be combined to provide 4 party
service, with two biased ringers across the line and one
each from tip and ring to ground.

The party line system installed in my grandparents' farm just rang
every phone in the valley, but with coded rings (one long, two short,
etc).

That was very common, though I don't know if Bell System
companies did it or not. When I was in grade school our
phone was two shorts, but that was an independant telco,
not a Bell operating company. I'm pretty sure that they
also used at least one of the above systems and that we
did not hear all of the rings. If I remember right
there were something like 16 parties on a line...

[Don Bowey]

Post by Floyd L. Davidson
...

Post by Richard Henry

Post by Floyd L. Davidson
But a "biased" ringer was also used. It had a spring
that pulled it to one side, and would respond to AC, but
with "pulsed DC" (for example a line with 52 VDC loop
voltage on it and superimposed AC ring current) it would
ring only if the polarity of the line was correct. A
two party line would use two of them, and at the CO the
line cards would be connected to the same line, but one
of them would be reversed tip and ring, and in the field
the phones would be wired with the same turnover. The
two systems could be combined to provide 4 party
service, with two biased ringers across the line and one
each from tip and ring to ground.

The party line system installed in my grandparents' farm just rang
every phone in the valley, but with coded rings (one long, two short,
etc).

That was very common, though I don't know if Bell System
companies did it or not. When I was in grade school our
phone was two shorts, but that was an independant telco,
not a Bell operating company. I'm pretty sure that they
also used at least one of the above systems and that we
did not hear all of the rings. If I remember right
there were something like 16 parties on a line...

Even into the 50s there were manual Bell offices.

As I recall, by the end of the 50s there were Independent Company Offices
(ICO) that even had their own AMA via their Stromberg X-Y offices, before
some of the Bell offices had CAMA in their SXS offices.

The ICs were motivated to upgrade their offices by very affordable
government loans. The scale of Bell upgrades was so great there wasn't
enough money or manpower to properly meet customer service needs, muchless
to relatively keep up with ICO upgrades. In 1956, Pacific Telephone
Northwest was split off of PT&T primarily so we could raise Capital to meet
our needs. At that time we still had some manual offices. It was sure
fun....

[h***@bbs.cpcn.com]

Post by Don Bowey
Even into the 50s there were manual Bell offices.

A fair number of subscribers still had manual service even in the
early 1960s. There was so much demand for new telephone service that
dial offices needed expansion in addition to manual offices being
converted. In addition, even those subscribers who had dial service
many could only dial within their own community, any calls beyond
their own C.O. required an operator until adequate trunk and tandem
exchanges could be built. Another challenge was finding land to build
a new dial CO. Bell System magazines from the 1950s show operators
and service reps working out of temporary trailers and other like
arrangements to meet high demand.

Still another problem in the 1950s was the Cold War and massive
defense spending. The Bell System was a major military contractor,
for both plain military phones and advanced fire control systems. A
lot of Western Electric capacity was tied up on top priority military
contracts in the 1950s. This became controversial in the later 1960s.

Whether an office was manual or dial did not affect party line
service. Dial service, including ESS, had to provide for it. (In a
number of states party line service is no longer offered at all, in a
few others it is limited to existing customers.)

The last Bell System manual office was on Santa Catalina Island, cut
over to ESS around 1980. The last major Independent manual office was
gone a few years later, but some very isolated oddball small
switchboards may still exist to this day or lasted until not long ago.

Party lines were once extremely common in cities as a way to save
money. In the 1940s a dollar a month was significant, and made the
difference for many people in affording a phone line or not. In the
1950s the demand for service was so high that people were forced to
have party lines due to insufficient capacity.

There was a Rock Hudson Doris Day comedy film "Pillow Talk" about
forced sharing a party line in 1960. That was a common problem back
then.

In cities party lines were more just 2 party or 4 party, and normally
the ringing was only to the person called. The Bell System used bias
and grounding to identify which of 2 or 4 parties to ring, the
independents used frequency. In rural areas coded ringing was
necessary because of so many people sharing a single line.

Post by Don Bowey
As I recall, by the end of the 50s there were Independent Company Offices
(ICO) that even had their own AMA via their Stromberg X-Y offices, before
some of the Bell offices had CAMA in their SXS offices.

In some cases a tiny office would be more economical to automate than
having an operator on duty 24/7 to handle occassional calls. The Bell
System developed less-cost AMA systems for small offices that weren't
as robost as a major city exchange.

[Al Gillis]

(Some snippage here)

Post by h***@bbs.cpcn.com
Whether an office was manual or dial did not affect party line
service. Dial service, including ESS, had to provide for it. (In a
number of states party line service is no longer offered at all, in a
few others it is limited to existing customers.)

In many cases, for reasons pertaining to switch hardware or cable plant,
party line customers were graded over to "private lines" (or more correctly,
single party lines) but their billing remained as multi-party, just as
they'd been for years. That way the Plant Department was happy (no more
party lines) and the customer was happy (lower rates for "party line
service"!).

[David Lesher]

Post by Al Gillis
In many cases, for reasons pertaining to switch hardware or cable plant,
party line customers were graded over to "private lines" (or more correctly,
single party lines) but their billing remained as multi-party, just as
they'd been for years. That way the Plant Department was happy (no more
party lines) and the customer was happy (lower rates for "party line
service"!).

Better; BTL/WeCo came up with "bridge lifters" -- a way to make
parties on 2 diverse cable legs parties on the same assignment.

So they'd be able to keep anyone play for party line service
exactly that, and no more....

[JosephKK]

Post by David Lesher

Post by Al Gillis
In many cases, for reasons pertaining to switch hardware or cable
plant, party line customers were graded over to "private lines" (or
more correctly, single party lines) but their billing remained as
multi-party, just as
they'd been for years. That way the Plant Department was happy (no
more party lines) and the customer was happy (lower rates for "party
line service"!).

Better; BTL/WeCo came up with "bridge lifters" -- a way to make
parties on 2 diverse cable legs parties on the same assignment.
So they'd be able to keep anyone play for party line service
exactly that, and no more....

Wow, a lot of interesting history has come to light in this
conversation. How about storing it in Wikipedia as well.

[Curtis R Anderson]

Post by h***@bbs.cpcn.com

Post by Don Bowey
Even into the 50s there were manual Bell offices.

A fair number of subscribers still had manual service even in the
early 1960s. There was so much demand for new telephone service that
dial offices needed expansion in addition to manual offices being
converted. In addition, even those subscribers who had dial service
many could only dial within their own community, any calls beyond
their own C.O. required an operator until adequate trunk and tandem
exchanges could be built. Another challenge was finding land to build
a new dial CO. Bell System magazines from the 1950s show operators
and service reps working out of temporary trailers and other like
arrangements to meet high demand.

My late father had lived in Rochester, NY while working at Kodak in the
way-back days. He remembered manual service before being transfered to
Chicago for a year or so. He returned to a Rochester suburb in the town
of Irondequoit, and by that time, the Norton St (ROCHNYXF) office might
have been converted to #5XB, or shortly after his move in 1960.

It appears that the "closer to downtown" offices had #1XB early on and
the five outer offices received #5XB as time went on.

How Rochester Telephone, a major independent operating company, fanagled
Western Electric into providing switches is probably best left as an
academic exercise. My aunt, who worked for RochTel for many years,
doesn't know the answer to that. Later, she did get me an old Kellogg
2554 set with an S-C G-type handset which I got to use while living on
my own.

Then my and my aunt's cousin lived in an outer suburb of Webster. She
had a party line back in the '70s as I remember seeing her S-C 554 wall
set in the kitchen, clearly showing a "party line code" on the card
insert. What type of office Webster had is unknown.

[Don Bowey]

Post by Curtis R Anderson

Post by h***@bbs.cpcn.com

Post by Don Bowey
Even into the 50s there were manual Bell offices.

A fair number of subscribers still had manual service even in the
early 1960s. There was so much demand for new telephone service that
dial offices needed expansion in addition to manual offices being
converted. In addition, even those subscribers who had dial service
many could only dial within their own community, any calls beyond
their own C.O. required an operator until adequate trunk and tandem
exchanges could be built. Another challenge was finding land to build
a new dial CO. Bell System magazines from the 1950s show operators
and service reps working out of temporary trailers and other like
arrangements to meet high demand.

My late father had lived in Rochester, NY while working at Kodak in the
way-back days. He remembered manual service before being transfered to
Chicago for a year or so. He returned to a Rochester suburb in the town
of Irondequoit, and by that time, the Norton St (ROCHNYXF) office might
have been converted to #5XB, or shortly after his move in 1960.
It appears that the "closer to downtown" offices had #1XB early on and
the five outer offices received #5XB as time went on.
How Rochester Telephone, a major independent operating company, fanagled
Western Electric into providing switches is probably best left as an
academic exercise.

Graybar was the WECO outlet to non-Bell telcos. Anything you wanted could
be purchased there.

Post by Curtis R Anderson
My aunt, who worked for RochTel for many years,
doesn't know the answer to that. Later, she did get me an old Kellogg
2554 set with an S-C G-type handset which I got to use while living on
my own.
Then my and my aunt's cousin lived in an outer suburb of Webster. She
had a party line back in the '70s as I remember seeing her S-C 554 wall
set in the kitchen, clearly showing a "party line code" on the card
insert. What type of office Webster had is unknown.

[h***@bbs.cpcn.com]

Post by Don Bowey
Graybar was the WECO outlet to non-Bell telcos. Anything you wanted could
be purchased there.

Graybar is still in business, www.graybar.com, selling communications
and other products.

They were one of the last companies to have a working Enterprise toll-
free number.

(Enterprise, known by a number of names, UX, WX, was the toll-free
service before 800 numbers, dating from at least the 1930s. You asked
the long distance operator for the Enterprise number, she looked up
the actual number and placed the call, automatically billing it as
collect. In the waning days numbers were still listed in white pages
but most were non working (the listings never got purged). AT&T
operators, the only ones who could make the connection, usually had no
idea how to do it and had to get a supervisor to dig out the
translation book. Given the much cheaper cost of dialed direct 800
calls, I'm surprised Enterprise numbers lasted as long as they did,
into the 1990s. For some reason most of the remaining listings
belonged to heavy industrial supply companies.)

[Don Bowey]

On 8/29/07 8:41 AM, in article

Post by h***@bbs.cpcn.com

Post by Don Bowey
Graybar was the WECO outlet to non-Bell telcos. Anything you wanted could
be purchased there.

Graybar is still in business, www.graybar.com, selling communications
and other products.
They were one of the last companies to have a working Enterprise toll-
free number.
(Enterprise, known by a number of names, UX, WX, was the toll-free
service before 800 numbers, dating from at least the 1930s. You asked
the long distance operator for the Enterprise number, she looked up
the actual number and placed the call, automatically billing it as
collect.

Cool - Manual WATS! With direct dial WATS, the number you dial is sent to a
database, which sends back the Switched Network real number. That is,
unless they have modernized the method.

Post by h***@bbs.cpcn.com
In the waning days numbers were still listed in white pages
but most were non working (the listings never got purged). AT&T
operators, the only ones who could make the connection, usually had no
idea how to do it and had to get a supervisor to dig out the
translation book. Given the much cheaper cost of dialed direct 800
calls, I'm surprised Enterprise numbers lasted as long as they did,
into the 1990s. For some reason most of the remaining listings
belonged to heavy industrial supply companies.)

[Rod Dorman]

Post by Don Bowey
On 8/29/07 8:41 AM, in article

Post by h***@bbs.cpcn.com
...
(Enterprise, known by a number of names, UX, WX, was the toll-free
service before 800 numbers, dating from at least the 1930s. You asked
the long distance operator for the Enterprise number, she looked up
the actual number and placed the call, automatically billing it as
collect.

Cool - Manual WATS! With direct dial WATS, the number you dial is sent to a
database, which sends back the Switched Network real number. That is,
unless they have modernized the method.

Anybody know if the California and Nevada Highway Patrols are still
accepting calls to Zenith 1-2000?

A quick look at their web sites doesn't show the number but it could
just mean they're tring to phase it out.

[Al Gillis]

Post by Rod Dorman

Post by Don Bowey
On 8/29/07 8:41 AM, in article

Post by h***@bbs.cpcn.com
...
(Enterprise, known by a number of names, UX, WX, was the toll-free
service before 800 numbers, dating from at least the 1930s. You asked
the long distance operator for the Enterprise number, she looked up
the actual number and placed the call, automatically billing it as
collect.

Cool - Manual WATS! With direct dial WATS, the number you dial is sent to a
database, which sends back the Switched Network real number. That is,
unless they have modernized the method.

Anybody know if the California and Nevada Highway Patrols are still
accepting calls to Zenith 1-2000?
A quick look at their web sites doesn't show the number but it could
just mean they're tring to phase it out.

A couple years ago the "official" Nevada state highway may referred
interested parties to the Zenith number. I don't know if that still works
or not - I'll be in Reno in a month or so and will try it out and report
back!

Al

[T]

Post by Al Gillis

Post by Rod Dorman

Post by Don Bowey
On 8/29/07 8:41 AM, in article

Post by h***@bbs.cpcn.com
...
(Enterprise, known by a number of names, UX, WX, was the toll-free
service before 800 numbers, dating from at least the 1930s. You asked
the long distance operator for the Enterprise number, she looked up
the actual number and placed the call, automatically billing it as
collect.

Cool - Manual WATS! With direct dial WATS, the number you dial is sent to a
database, which sends back the Switched Network real number. That is,
unless they have modernized the method.

Anybody know if the California and Nevada Highway Patrols are still
accepting calls to Zenith 1-2000?
A quick look at their web sites doesn't show the number but it could
just mean they're tring to phase it out.

A couple years ago the "official" Nevada state highway may referred
interested parties to the Zenith number. I don't know if that still works
or not - I'll be in Reno in a month or so and will try it out and report
back!
Al

With the advent of cell phones there are now usually three button calls
for state police etc. In RI it's *77 to reach the Rhode Island State
Police.

[Richard Henry]

Post by T

Post by Al Gillis

Post by Rod Dorman

Post by Don Bowey
On 8/29/07 8:41 AM, in article

Post by h***@bbs.cpcn.com
...
(Enterprise, known by a number of names, UX, WX, was the toll-free
service before 800 numbers, dating from at least the 1930s. You asked
the long distance operator for the Enterprise number, she looked up
the actual number and placed the call, automatically billing it as
collect.

Cool - Manual WATS! With direct dial WATS, the number you dial is sent to a
database, which sends back the Switched Network real number. That is,
unless they have modernized the method.

Anybody know if the California and Nevada Highway Patrols are still
accepting calls to Zenith 1-2000?
A quick look at their web sites doesn't show the number but it could
just mean they're tring to phase it out.

A couple years ago the "official" Nevada state highway may referred
interested parties to the Zenith number. I don't know if that still works
or not - I'll be in Reno in a month or so and will try it out and report
back!
Al

With the advent of cell phones there are now usually three button calls
for state police etc. In RI it's *77 to reach the Rhode Island State
Police.- Hide quoted text -
- Show quoted text -

911 works. I have called 911 on my cell phone twice. Once when I
witnesses an aircraft midair collision, and once when I sat down with
my phone in my back pocket.

[h***@bbs.cpcn.com]

Post by Richard Henry
911 works. I have called 911 on my cell phone twice. Once when I
witnesses an aircraft midair collision, and once when I sat down with
my phone in my back pocket.- Hide quoted text -

But do _all_ emergency dispatching centers have the capability to
read and interpret a GPS signal from the cell phone? I suspect at
this point in time most do not.

[Jim Thompson]

Post by h***@bbs.cpcn.com

Post by Richard Henry
911 works. I have called 911 on my cell phone twice. Once when I
witnesses an aircraft midair collision, and once when I sat down with
my phone in my back pocket.- Hide quoted text -

But do _all_ emergency dispatching centers have the capability to
read and interpret a GPS signal from the cell phone? I suspect at
this point in time most do not.

I believe you are _required_ to have a GPS-capable phone on the
Verizon network here in Arizona, effective 1/1/2008.

...Jim Thompson

[PeterD]

On Fri, 31 Aug 2007 07:29:50 -0700, Jim Thompson

Post by Jim Thompson

Post by h***@bbs.cpcn.com

Post by Richard Henry
911 works. I have called 911 on my cell phone twice. Once when I
witnesses an aircraft midair collision, and once when I sat down with
my phone in my back pocket.- Hide quoted text -

But do _all_ emergency dispatching centers have the capability to
read and interpret a GPS signal from the cell phone? I suspect at
this point in time most do not.

I believe you are _required_ to have a GPS-capable phone on the
Verizon network here in Arizona, effective 1/1/2008.
...Jim Thompson

Federal law (FCC regs) require all new activations be GPS enabled
phones. Been that wayfor several years. Whether the system (e-911) can
handle it ina given area is another issue!

[Terry]

Post by PeterD
On Fri, 31 Aug 2007 07:29:50 -0700, Jim Thompson

Post by Jim Thompson

Post by h***@bbs.cpcn.com

Post by Richard Henry
911 works. I have called 911 on my cell phone twice. Once when I
witnesses an aircraft midair collision, and once when I sat down with
my phone in my back pocket.- Hide quoted text -

But do _all_ emergency dispatching centers have the capability to
read and interpret a GPS signal from the cell phone? I suspect at
this point in time most do not.

I believe you are _required_ to have a GPS-capable phone on the
Verizon network here in Arizona, effective 1/1/2008.
...Jim Thompson

Federal law (FCC regs) require all new activations be GPS enabled
phones. Been that wayfor several years. Whether the system (e-911) can
handle it ina given area is another issue!

Is there a list, table, or something that tells what phones have this ?

TerryS

[Jim Thompson]

Post by Terry

Post by PeterD
On Fri, 31 Aug 2007 07:29:50 -0700, Jim Thompson

Post by Jim Thompson

Post by h***@bbs.cpcn.com

Post by Richard Henry
911 works. I have called 911 on my cell phone twice. Once when I
witnesses an aircraft midair collision, and once when I sat down with
my phone in my back pocket.- Hide quoted text -

But do _all_ emergency dispatching centers have the capability to
read and interpret a GPS signal from the cell phone? I suspect at
this point in time most do not.

I believe you are _required_ to have a GPS-capable phone on the
Verizon network here in Arizona, effective 1/1/2008.
...Jim Thompson

Federal law (FCC regs) require all new activations be GPS enabled
phones. Been that wayfor several years. Whether the system (e-911) can
handle it ina given area is another issue!

Is there a list, table, or something that tells what phones have this ?
TerryS

Verizon has a list. I would imagine the other service providers have
a list as well.

...Jim Thompson

[h***@bbs.cpcn.com]

Post by Rod Dorman
Anybody know if the California and Nevada Highway Patrols are still
accepting calls to Zenith 1-2000?

Zenith was another name for Enterprise. Also was UX and WX.

It's not so much if they'll accept the call as the called party isn't
asked, it automatically goes through.

Rather, it's more if an operator today knows what to do with that
request. Even back when the service was still working most operators
didn't know about it, and one had to insist on a supervisor or senior
person who knew about it, then they had to dig up the conversion
table.

I believe someone said Alaska police used it as well. Don't know if
still true.

[T]

Post by h***@bbs.cpcn.com

Post by Rod Dorman
Anybody know if the California and Nevada Highway Patrols are still
accepting calls to Zenith 1-2000?

Zenith was another name for Enterprise. Also was UX and WX.
It's not so much if they'll accept the call as the called party isn't
asked, it automatically goes through.
Rather, it's more if an operator today knows what to do with that
request. Even back when the service was still working most operators
didn't know about it, and one had to insist on a supervisor or senior
person who knew about it, then they had to dig up the conversion
table.
I believe someone said Alaska police used it as well. Don't know if
still true.

I love the assumption that there IS an operator. With VoIP you get no
such beast.

[Gary Tait]

Post by h***@bbs.cpcn.com

Post by Rod Dorman
Anybody know if the California and Nevada Highway Patrols are still
accepting calls to Zenith 1-2000?

Zenith was another name for Enterprise. Also was UX and WX.

Oh, I remember that.

The Ontario Provincial Police were Zenith Fifty-Thousand.

[Richard Henry]

Post by Floyd L. Davidson
...

Post by Richard Henry

Post by Floyd L. Davidson
But a "biased" ringer was also used. It had a spring
that pulled it to one side, and would respond to AC, but
with "pulsed DC" (for example a line with 52 VDC loop
voltage on it and superimposed AC ring current) it would
ring only if the polarity of the line was correct. A
two party line would use two of them, and at the CO the
line cards would be connected to the same line, but one
of them would be reversed tip and ring, and in the field
the phones would be wired with the same turnover. The
two systems could be combined to provide 4 party
service, with two biased ringers across the line and one
each from tip and ring to ground.

The party line system installed in my grandparents' farm just rang
every phone in the valley, but with coded rings (one long, two short,
etc).

That was very common, though I don't know if Bell System
companies did it or not. When I was in grade school our
phone was two shorts, but that was an independant telco,
not a Bell operating company. I'm pretty sure that they
also used at least one of the above systems and that we
did not hear all of the rings. If I remember right
there were something like 16 parties on a line...

After a little internet search, I found this old telephone directory
page from Waitsfield and Fayston Telephone Co. in a genealogical site.

http://freepages.genealogy.rootsweb.com/~nekg3/phones/waitsfield-1.htm

The numbers are listed by "line" and "ring". Note the broadcast rings
at the top of the page. The line through N. Fayston is line 16, the
one I remember.

[Gary Tait]

Post by Richard Henry

Post by Floyd L. Davidson

Post by Richard Henry
The party line system installed in my grandparents' farm just rang
every phone in the valley, but with coded rings (one long, two short,
etc).

We had a party line until 1980 or so, on our smallish independant phone
company. By my time, I think it was only 2-3 customers per line.

Post by Richard Henry

Post by Floyd L. Davidson
That was very common, though I don't know if Bell System
companies did it or not. When I was in grade school our
phone was two shorts, but that was an independant telco,
not a Bell operating company. I'm pretty sure that they
also used at least one of the above systems and that we
did not hear all of the rings. If I remember right
there were something like 16 parties on a line...

The multi-grounding thing was used with the distinctive rings.
I do know or old 500 wall rotary set was wired with a ground wire.

Post by Richard Henry
After a little internet search, I found this old telephone directory
page from Waitsfield and Fayston Telephone Co. in a genealogical site.
http://freepages.genealogy.rootsweb.com/~nekg3/phones/waitsfield-1.htm
The numbers are listed by "line" and "ring". Note the broadcast rings
at the top of the page. The line through N. Fayston is line 16, the
one I remember.

That ended in the 50s, when dial phones started. The old man doesn't
remember those numbers, but has the same number they first issued with
the dial phones.

[David Lesher]

Post by Floyd L. Davidson

Post by David Lesher
And BTW, Ma never used frequency selective ringing; only independents did.
(Another poster asked "Why 20 hz?" and I echo that question...)

I don't remember ever seeing anything definitive, but
what your original post described did in fact sound like
Larry Lippman or maybe Al Varney. It used to be really
interesting reading what they had to say...

Agreed. Lots to learn from them.

BTW, I chatted with Al ~5 years ago...

Post by Floyd L. Davidson
There originally had been 135 Hz ring systems between
offices. Those also do not travel well, but when used
with a repeatered system, every other segment could be
20 Hz and the ones in between 135 Hz. In that way it
was possible to build a repeater that could pass
signaling.
Carrier systems made that unworkable too. The first
signaling to replace 20 Hz and 135 Hz for carrier
systems was 1000 Hz signaling. That was followed by a
number of things, mainly selective signaling (SS-1) that
used two tones, and eventually the well known 2600 Hz
(and less known 2400 Hz) Single Frequency (SF) system.

Things I never knew; thanks. I recall Lorain Products Loop Extenders that
did weird things re: ringing, but not what they did.

[Jeff Liebermann]

Post by Floyd L. Davidson

Post by David Lesher
Nope, the standard ringer is not tuned to 20 Hz. It responds {at least} to 30 hz and
other frequencies, can't recall how low...

Including 60 Hz.

20, 25, 30, 60Hz +/-5%.
I have a telephone line simulator/tester that will do all of those:
<http://www.teltone.com/products/simulators/tls5/home.htm>
Well, I had one, as I loaned it to someone and forgot whom.

There are more frequencies available:
<http://www.freepatentsonline.com/4653093.html>
but I don't think Ma Bell ever used selective ring. As I recall when
I worked for Ma Bell in the late 1960's, there was only one "ring bus"
on the frame which was 20Hz. Incidentally, everyone got fried by the
ring bus exactly once.
"Harmonic, decimonic and synchromonic series ringing systems
generally are employed in the telephone service industry.
The harmonic series are 16.6, 25, 33.3, 50, and 66.6 Hertz.
Decimonic series are provided as 20, 30, 40, 50 and 60 Hertz,
while the synchromonic series are 16 (or 20), 30, 42, 54, and
66 Hertz."

[Floyd L. Davidson]

Post by Jeff Liebermann
I worked for Ma Bell in the late 1960's, there was only one "ring bus"
on the frame which was 20Hz. Incidentally, everyone got fried by the
ring bus exactly once.

Don't you just *love* getting your arm jerked from here
to there at 20 jerks per second! Makes the arm feel
like it just ran a marithon.

I'm not sure about a CO, but in a typical long distance
office the ring bus has no interrupter on it. Straight
105VAC at 20 Hz which doesn't stop and let you off every
couple seconds... that is *nasty* stuff.

[Don Bowey]

Post by Floyd L. Davidson

Post by Jeff Liebermann
I worked for Ma Bell in the late 1960's, there was only one "ring bus"
on the frame which was 20Hz. Incidentally, everyone got fried by the
ring bus exactly once.

Don't you just *love* getting your arm jerked from here
to there at 20 jerks per second! Makes the arm feel
like it just ran a marithon.
I'm not sure about a CO, but in a typical long distance
office the ring bus has no interrupter on it. Straight
105VAC at 20 Hz which doesn't stop and let you off every
couple seconds... that is *nasty* stuff.

And then there were the 130VDC + and - battery Ttaps for the telegraph (TTY)
testboard. Also Ouch.

[Jeff Liebermann]

Post by Floyd L. Davidson

Post by Jeff Liebermann
I worked for Ma Bell in the late 1960's, there was only one "ring bus"
on the frame which was 20Hz. Incidentally, everyone got fried by the
ring bus exactly once.

Don't you just *love* getting your arm jerked from here
to there at 20 jerks per second! Makes the arm feel
like it just ran a marithon.

I still remember it today. It was a rite of initiation at the CO.
Everyone that worked on the frame had to get zapped at least once or
they were reviled as being excessively careful. Those that got zapped
more than once, were deemed excessively sloppy. I'll confess to
getting fried twice, once while on a ladder. Incidentally, this was
in the daze before everyone wore helmets so I managed to bounce off
the rack a few times before hitting concrete. Ouch.

Post by Floyd L. Davidson
I'm not sure about a CO, but in a typical long distance
office the ring bus has no interrupter on it. Straight
105VAC at 20 Hz which doesn't stop and let you off every
couple seconds... that is *nasty* stuff.

Yep. Continuous ring. Great way to identify the line and drive the
customers nuts. Apply continuous ring to their line and go do
something else for a while. After a few minutes, the test board would
pass on a call that someone's phone was "stuck" in ring. That was
sufficient to identify the line. The practice was officially
discouraged, but still used when necessary. I also had a line tracer
consisting of the guts from a ringer, the resonating capacitor, and
the leads shorted together. There was enough inductive pickup to
barely ring the bell by induction. That practice was also officially
discouraged, but there were such ringers in almost everyone's tool
kit.

[Michael A. Terrell]

Post by Jeff Liebermann

Post by Floyd L. Davidson

Post by Jeff Liebermann
I worked for Ma Bell in the late 1960's, there was only one "ring bus"
on the frame which was 20Hz. Incidentally, everyone got fried by the
ring bus exactly once.

Don't you just *love* getting your arm jerked from here
to there at 20 jerks per second! Makes the arm feel
like it just ran a marithon.

I still remember it today. It was a rite of initiation at the CO.
Everyone that worked on the frame had to get zapped at least once or
they were reviled as being excessively careful. Those that got zapped
more than once, were deemed excessively sloppy. I'll confess to
getting fried twice, once while on a ladder. Incidentally, this was
in the daze before everyone wore helmets so I managed to bounce off
the rack a few times before hitting concrete. Ouch.

Post by Floyd L. Davidson
I'm not sure about a CO, but in a typical long distance
office the ring bus has no interrupter on it. Straight
105VAC at 20 Hz which doesn't stop and let you off every
couple seconds... that is *nasty* stuff.

Yep. Continuous ring. Great way to identify the line and drive the
customers nuts. Apply continuous ring to their line and go do
something else for a while. After a few minutes, the test board would
pass on a call that someone's phone was "stuck" in ring. That was
sufficient to identify the line. The practice was officially
discouraged, but still used when necessary. I also had a line tracer
consisting of the guts from a ringer, the resonating capacitor, and
the leads shorted together. There was enough inductive pickup to
barely ring the bell by induction. That practice was also officially
discouraged, but there were such ringers in almost everyone's tool
kit.

I thought that it was weird to see an electronic ring generator for
sale in a local surplus store, while the local CO was still all
mechanical.

[Mark]

Post by Jeff Liebermann
Yep. Continuous ring. Great way to identify the line and drive the
customers nuts. Apply continuous ring to their line and go do
something else for a while. After a few minutes, the test board would
pass on a call that someone's phone was "stuck" in ring. That was
sufficient to identify the line. The practice was officially
discouraged, but still used when necessary. ....

Wow, I remember way back as a kid, one night our phone started to ring
continnuously woke us all up and didn't stop even after we picked up
all the phones... My dad ran into the basement and disconnected the
wires...

I never knew what that was about.....till now...

So tell me how was the customer supposed to call in and report a
problem if their phone is ringing continuously....?


Mark

[Michael A. Terrell]

Post by Mark

Post by Jeff Liebermann
Yep. Continuous ring. Great way to identify the line and drive the
customers nuts. Apply continuous ring to their line and go do
something else for a while. After a few minutes, the test board would
pass on a call that someone's phone was "stuck" in ring. That was
sufficient to identify the line. The practice was officially
discouraged, but still used when necessary. ....

Wow, I remember way back as a kid, one night our phone started to ring
continnuously woke us all up and didn't stop even after we picked up
all the phones... My dad ran into the basement and disconnected the
wires...
I never knew what that was about.....till now...
So tell me how was the customer supposed to call in and report a
problem if their phone is ringing continuously....?
Mark

Take it off the hook and dial the service number?

[Floyd L. Davidson]

Post by Michael A. Terrell

Post by Mark

Post by Jeff Liebermann
Yep. Continuous ring. Great way to identify the line and drive the
customers nuts. Apply continuous ring to their line and go do
something else for a while. After a few minutes, the test board would
pass on a call that someone's phone was "stuck" in ring. That was
sufficient to identify the line. The practice was officially
discouraged, but still used when necessary. ....

Wow, I remember way back as a kid, one night our phone started to ring
continnuously woke us all up and didn't stop even after we picked up
all the phones... My dad ran into the basement and disconnected the
wires...
I never knew what that was about.....till now...
So tell me how was the customer supposed to call in and report a
problem if their phone is ringing continuously....?
Mark

Take it off the hook and dial the service number?

With a shoe on the line that has continuous ring on it?
No dialtone... just a blast of loud 20 Hz in the ear.

I never worked for a LEC, and hence rarely ever worked
on POTS subscriber lines, but 20 Hz continuous ringing
did have other uses. Originally it was available on
2-wire testboards (18B Testboards were the ones I worked
at) that interfaced with cable heads. There was a front
row of cords and a back row, and one particular key
labeled RING of course, could be pushed forward or
backward to connect ring current to front or back cords
as desired, with the cord inserted into the Primary
Jack for any given cable pair one wanted to "ring".

The typical use we found for this was with a lot of the
leased lines using those new fangled things called modems,
instead of teletype loops (which had anything from 20ma
to 60ma of current pulsing on them all the time).

Seems that every now and then a leased line with no
current on it (no loop current or no teletype current)
would get a static charge built up on the line, and it
would simply go dead, with no continuity for the voice
path. Most of the time just putting a test set on the
line would clear it, but we discovered that a 100%
guaranteed fix was to zap the line with a few seconds of
ring voltage! So that became pretty common... until
most leased lines began to be equipped with "sealing
current" modules to avoid the problem.

[Bob]

Post by Floyd L. Davidson

Post by Michael A. Terrell

Post by Mark

Post by Jeff Liebermann
Yep. Continuous ring. Great way to identify the line and drive the
customers nuts. Apply continuous ring to their line and go do
something else for a while. After a few minutes, the test board would
pass on a call that someone's phone was "stuck" in ring. That was
sufficient to identify the line. The practice was officially
discouraged, but still used when necessary. ....

Wow, I remember way back as a kid, one night our phone started to ring
continnuously woke us all up and didn't stop even after we picked up
all the phones... My dad ran into the basement and disconnected the
wires...
I never knew what that was about.....till now...
So tell me how was the customer supposed to call in and report a
problem if their phone is ringing continuously....?
Mark

Take it off the hook and dial the service number?

With a shoe on the line that has continuous ring on it?
No dialtone... just a blast of loud 20 Hz in the ear.
I never worked for a LEC, and hence rarely ever worked
on POTS subscriber lines, but 20 Hz continuous ringing
did have other uses. Originally it was available on
2-wire testboards (18B Testboards were the ones I worked
at) that interfaced with cable heads. There was a front
row of cords and a back row, and one particular key
labeled RING of course, could be pushed forward or
backward to connect ring current to front or back cords
as desired, with the cord inserted into the Primary
Jack for any given cable pair one wanted to "ring".
The typical use we found for this was with a lot of the
leased lines using those new fangled things called modems,
instead of teletype loops (which had anything from 20ma
to 60ma of current pulsing on them all the time).
Seems that every now and then a leased line with no
current on it (no loop current or no teletype current)
would get a static charge built up on the line, and it
would simply go dead, with no continuity for the voice
path. Most of the time just putting a test set on the
line would clear it, but we discovered that a 100%
guaranteed fix was to zap the line with a few seconds of
ring voltage! So that became pretty common... until
most leased lines began to be equipped with "sealing
current" modules to avoid the problem.
--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>

Floyd,

That is weird. How did a static charge keep that "dry" leased line from
working?

By the way -- I see you're in Alaska. Have you ever had any dealings with
Witham Reeve?

Bob

[Don Bowey]

On 8/31/07 9:32 PM, in article

Post by Bob

Post by Floyd L. Davidson

Post by Michael A. Terrell

Post by Mark

Post by Jeff Liebermann
Yep. Continuous ring. Great way to identify the line and drive the
customers nuts. Apply continuous ring to their line and go do
something else for a while. After a few minutes, the test board would
pass on a call that someone's phone was "stuck" in ring. That was
sufficient to identify the line. The practice was officially
discouraged, but still used when necessary. ....

Wow, I remember way back as a kid, one night our phone started to ring
continnuously woke us all up and didn't stop even after we picked up
all the phones... My dad ran into the basement and disconnected the
wires...
I never knew what that was about.....till now...
So tell me how was the customer supposed to call in and report a
problem if their phone is ringing continuously....?
Mark

Take it off the hook and dial the service number?

With a shoe on the line that has continuous ring on it?
No dialtone... just a blast of loud 20 Hz in the ear.
I never worked for a LEC, and hence rarely ever worked
on POTS subscriber lines, but 20 Hz continuous ringing
did have other uses. Originally it was available on
2-wire testboards (18B Testboards were the ones I worked
at) that interfaced with cable heads. There was a front
row of cords and a back row, and one particular key
labeled RING of course, could be pushed forward or
backward to connect ring current to front or back cords
as desired, with the cord inserted into the Primary
Jack for any given cable pair one wanted to "ring".
The typical use we found for this was with a lot of the
leased lines using those new fangled things called modems,
instead of teletype loops (which had anything from 20ma
to 60ma of current pulsing on them all the time).
Seems that every now and then a leased line with no
current on it (no loop current or no teletype current)
would get a static charge built up on the line, and it
would simply go dead, with no continuity for the voice
path. Most of the time just putting a test set on the
line would clear it, but we discovered that a 100%
guaranteed fix was to zap the line with a few seconds of
ring voltage! So that became pretty common... until
most leased lines began to be equipped with "sealing
current" modules to avoid the problem.
--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>

Floyd,
That is weird. How did a static charge keep that "dry" leased line from
working?

What it really was, was a high-resistance splice caused by oxides on the
wires. Most any voltage would "seal" it again.

Post by Bob
By the way -- I see you're in Alaska. Have you ever had any dealings with
Witham Reeve?
Bob

[Bob]

"Don Bowey" <***@comcast.net> wrote"
[snip]

Post by Don Bowey

Post by Bob
That is weird. How did a static charge keep that "dry" leased line from
working?

What it really was, was a high-resistance splice caused by oxides on the
wires. Most any voltage would "seal" it again.

Ahhh. I see.

My POTS line gets noisy some times. Maybe because I rarely use it. The best
cure seems to be to get my line to ring and then go offhook in the middle of
the ringing. It works every time (for a while).

Bob

[Floyd L. Davidson]

Post by Bob
Floyd,
That is weird. How did a static charge keep that "dry" leased line from
working?

If the static charge is higher than the signal level...
the continuity for signal is zilch. The real cause
though is corrosion from dampness and poor insulation at
splice boxes and connectors. The corrosion causes
various effects (resistance, diode effects, and
capacitance) that allow a charge to build up and be
maintained at a higher voltage than the signal. At that
point, the line goes totally dead. Usually just a lower
resistance (for example plugging in a test set on the
line) would dump the charge and make it work again.
That didn't change the cause though. On the other hand,
hitting the line with 100 VAC of 20 Hz ring voltage
would often change the electrical characteristics of the
corrosion, at least for awhile.

That was not something commonly experienced until the
1960's or so, but it became a very common problem with
"dry" lines used for leased line modems. Today any line
that does not have a DC current on it otherwise will be
equipped with a sealing current module, which puts a DC
current on it (usually using about 24 VDC and about
10-20ma).

Post by Bob
By the way -- I see you're in Alaska. Have you ever had any dealings with
Witham Reeve?

Which of the 600,000 people in Alaska would Witham Reeve
be? And does he live in Los Anchorage, or actually in
Alaska? ;-)

[Bob]

Post by Floyd L. Davidson

Post by Bob
Floyd,
That is weird. How did a static charge keep that "dry" leased line from
working?

If the static charge is higher than the signal level...
the continuity for signal is zilch. The real cause
though is corrosion from dampness and poor insulation at
splice boxes and connectors. The corrosion causes
various effects (resistance, diode effects, and
capacitance) that allow a charge to build up and be
maintained at a higher voltage than the signal. At that
point, the line goes totally dead. Usually just a lower
resistance (for example plugging in a test set on the
line) would dump the charge and make it work again.
That didn't change the cause though. On the other hand,
hitting the line with 100 VAC of 20 Hz ring voltage
would often change the electrical characteristics of the
corrosion, at least for awhile.
That was not something commonly experienced until the
1960's or so, but it became a very common problem with
"dry" lines used for leased line modems. Today any line
that does not have a DC current on it otherwise will be
equipped with a sealing current module, which puts a DC
current on it (usually using about 24 VDC and about
10-20ma).

Post by Bob
By the way -- I see you're in Alaska. Have you ever had any dealings with
Witham Reeve?

Which of the 600,000 people in Alaska would Witham Reeve
be? And does he live in Los Anchorage, or actually in
Alaska? ;-)
--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>

Floyd,

Whitham owns and runs a telecom engineering group in Anchorage, but I think
he's retired, now. He has written several books that are "bibles" for the
design side of the business. Here is one of them:

http://www.amazon.com/Subscriber-Signaling-Transmission-Handbook-Telecommunications/dp/0780347463/ref=sr_1_10/104-8764114-3844731?ie=UTF8&s=books&qid=1188623424&sr=1-10

...and here's his website:

http://www.reeve.com/

He is a very knowledgeable and likeable guy. On a side note, I was watching
a tv show about early Alaskan bush pilots and they spent a bit of time on a
guy named Bob Reeve. It got me curious, and after a little digging on the
web I learned that Bob Reeve is Whitham's father. I then started singing the
Disney song "It's a Small World". 8-)

Bob

[Terry]

Post by Jeff Liebermann

Post by Floyd L. Davidson

Post by David Lesher
Nope, the standard ringer is not tuned to 20 Hz. It responds {at least} to 30 hz and
other frequencies, can't recall how low...

Including 60 Hz.

20, 25, 30, 60Hz +/-5%.
<http://www.teltone.com/products/simulators/tls5/home.htm>
Well, I had one, as I loaned it to someone and forgot whom.
<http://www.freepatentsonline.com/4653093.html>
but I don't think Ma Bell ever used selective ring. As I recall when
I worked for Ma Bell in the late 1960's, there was only one "ring bus"
on the frame which was 20Hz. Incidentally, everyone got fried by the
ring bus exactly once.
"Harmonic, decimonic and synchromonic series ringing systems
generally are employed in the telephone service industry.
The harmonic series are 16.6, 25, 33.3, 50, and 66.6 Hertz.
Decimonic series are provided as 20, 30, 40, 50 and 60 Hertz,
while the synchromonic series are 16 (or 20), 30, 42, 54, and
66 Hertz."
--
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Do you have any idea what the base frequency these are derived from. I
cannot make the math come out. One tidbit I found on the net was why A & B
RENs. An A REN is referenced to a electromechanical tuned ringer of 20 or
30HZ. And a B REN to the same of 15 to 68 hz, excepting 20 or 30.

TerryS

[Jeff Liebermann]

Post by Terry

Post by Jeff Liebermann

Post by Floyd L. Davidson

Post by David Lesher
Nope, the standard ringer is not tuned to 20 Hz. It responds {at least} to 30 hz and
other frequencies, can't recall how low...

Including 60 Hz.

20, 25, 30, 60Hz +/-5%.
<http://www.teltone.com/products/simulators/tls5/home.htm>
Well, I had one, as I loaned it to someone and forgot whom.
<http://www.freepatentsonline.com/4653093.html>
but I don't think Ma Bell ever used selective ring. As I recall when
I worked for Ma Bell in the late 1960's, there was only one "ring bus"
on the frame which was 20Hz. Incidentally, everyone got fried by the
ring bus exactly once.
"Harmonic, decimonic and synchromonic series ringing systems
generally are employed in the telephone service industry.
The harmonic series are 16.6, 25, 33.3, 50, and 66.6 Hertz.
Decimonic series are provided as 20, 30, 40, 50 and 60 Hertz,
while the synchromonic series are 16 (or 20), 30, 42, 54, and
66 Hertz."

Do you have any idea what the base frequency these are derived from. I
cannot make the math come out. One tidbit I found on the net was why A & B
RENs. An A REN is referenced to a electromechanical tuned ringer of 20 or
30HZ. And a B REN to the same of 15 to 68 hz, excepting 20 or 30.
TerryS

Incidentally, did you notice that the patent was issued in 1985?
That's because the old patent had expired and various people were
repackaging old patents and repatenting them. The dead (technology)
shall rise again. There's quite a bit in the background section, much
of which I fail to understand.

It wasn't called a "ring generator" for nothing. (Not a "ring tone
generator" which is something quite different). It really was a DC
motor -> AC generator.

I have no idea if there is a base frequency for ringers. As I vaguely
recall from CWT (Cal Drip and Tinkle) prior to when GTE bought them in
1967(?), they had party lines with seperate ring frequencies. I
recall that they used a motor-generator that started at -48VDC, and
fed several gearboxes with multiple generators attached to generate
the other frequencies. However, I don't recall what it looked like. I
tried to find a photo of the contraption online but couldn't. I may
have something in some old BSP's.

Also, as I recall, selective ring didn't work with the later Model 500
phones. It only worked with the WE 300 party line series ("lift
plunger to dial or talk") such as:
<http://mysite.verizon.net/paul-f/we300typ.htm>
<http://mysite.verizon.net/paul-f/we307.html>
There were some Model 500's that worked on party lines, but they were
not the selective frequency ring flavor:
<http://mysite.verizon.net/paul-f/we500typ.htm#Party_Line>

[Terry]

Post by Jeff Liebermann

Post by Terry

Post by Jeff Liebermann

Post by Floyd L. Davidson

Post by David Lesher
Nope, the standard ringer is not tuned to 20 Hz. It responds {at least} to 30 hz and
other frequencies, can't recall how low...

Including 60 Hz.

20, 25, 30, 60Hz +/-5%.
<http://www.teltone.com/products/simulators/tls5/home.htm>
Well, I had one, as I loaned it to someone and forgot whom.
<http://www.freepatentsonline.com/4653093.html>
but I don't think Ma Bell ever used selective ring. As I recall when
I worked for Ma Bell in the late 1960's, there was only one "ring bus"
on the frame which was 20Hz. Incidentally, everyone got fried by the
ring bus exactly once.
"Harmonic, decimonic and synchromonic series ringing systems
generally are employed in the telephone service industry.
The harmonic series are 16.6, 25, 33.3, 50, and 66.6 Hertz.
Decimonic series are provided as 20, 30, 40, 50 and 60 Hertz,
while the synchromonic series are 16 (or 20), 30, 42, 54, and
66 Hertz."

Do you have any idea what the base frequency these are derived from. I
cannot make the math come out. One tidbit I found on the net was why A & B
RENs. An A REN is referenced to a electromechanical tuned ringer of 20 or
30HZ. And a B REN to the same of 15 to 68 hz, excepting 20 or 30.
TerryS

Incidentally, did you notice that the patent was issued in 1985?
That's because the old patent had expired and various people were
repackaging old patents and repatenting them. The dead (technology)
shall rise again. There's quite a bit in the background section, much
of which I fail to understand.
It wasn't called a "ring generator" for nothing. (Not a "ring tone
generator" which is something quite different). It really was a DC
motor -> AC generator.
I have no idea if there is a base frequency for ringers. As I vaguely
recall from CWT (Cal Drip and Tinkle) prior to when GTE bought them in
1967(?), they had party lines with seperate ring frequencies. I
recall that they used a motor-generator that started at -48VDC, and
fed several gearboxes with multiple generators attached to generate
the other frequencies. However, I don't recall what it looked like. I
tried to find a photo of the contraption online but couldn't. I may
have something in some old BSP's.
Also, as I recall, selective ring didn't work with the later Model 500
phones. It only worked with the WE 300 party line series ("lift
<http://mysite.verizon.net/paul-f/we300typ.htm>
<http://mysite.verizon.net/paul-f/we307.html>
There were some Model 500's that worked on party lines, but they were
<http://mysite.verizon.net/paul-f/we500typ.htm#Party_Line>
--
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

The party line ringer at my place was a seperate box with taps.

TerryS

[Charlie Edmondson]

Post by Jeff Liebermann
<http://www.freepatentsonline.com/4653093.html>
but I don't think Ma Bell ever used selective ring. As I recall when
I worked for Ma Bell in the late 1960's, there was only one "ring bus"
on the frame which was 20Hz. Incidentally, everyone got fried by the
ring bus exactly once.

Oh, I worked on the frame in the Palm Desert CO for a year, and then the
Crestline CO after that, and many the time did I reach throught with a
bare, sweaty arm just as someone rang through. You reach in, when ZAP!
the ring voltage hits. BAM! as your arm reflexes up, and you hit your
arm on the pins of the block above. OUCH! as your arm goes back down,
just in time to get hit by the next burst of ring voltage... 8-)

Charlie

[Don Bowey]

Post by David Lesher

Post by Terry

Post by David Lesher
There was some very clever aspect of the whole design of the ringer
magnetics that solved the issue. THAT's what I'm interested in learning
about.

Well, the standard bell must have been tuned to 20hz, thats just good power
economics, and it would not respond to transients, or 60hz pickup. With a
standard 2 on 4 off cycle, I bet that one third of the bells all rang at the
same time. Just to keep the load on the generator constant. Note that a
party line would have bells tuned to different frequencies.

Nope, the standard ringer is not tuned to 20 Hz. It responds {at least} to 30 hz and
other frequencies, can't recall how low...
Again, generator load is not relevant to my question...

OK. It was hard to tell from the post to which I responded:
"If you look at my origianl query, you can see I was addressing the far
less obvious issue of getting enough power down the far-from-ideal line
to run the ringers. THAT is what I still seek insight into....">

Post by David Lesher
And BTW, Ma never used frequency selective ringing; only independents did.

You are generally correct, but we did own a few. There were occasions where
a Regional Bell company and an Independent would trade operating areas,
including ALL plant in place. Until the central offices could be upgraded,
we had a variety of mechanical offices.

Post by David Lesher
(Another poster asked "Why 20 hz?" and I echo that question...)

[h***@bbs.cpcn.com]

Post by David Lesher
Again, generator load is not relevant to my question...

I would suggest reading the first volume of the Bell System
"Engineering & Science" history. It's available in larger libraries.
That goes into detail about the development of the earliest telephone
instruments and components of each instrument. The local loop is part
of that discussion and may also answer your question. (They spend a
great deal talking about the pros and cons of loading coils, for
instance.)

As to my earlier comment about "fence posts", I meant wire fencing
using in some rural areas which was used as a telephone conductor.
Obviously not the best.

[Terry]

Post by h***@bbs.cpcn.com

Post by David Lesher
Again, generator load is not relevant to my question...

I would suggest reading the first volume of the Bell System
"Engineering & Science" history. It's available in larger libraries.
That goes into detail about the development of the earliest telephone
instruments and components of each instrument. The local loop is part
of that discussion and may also answer your question. (They spend a
great deal talking about the pros and cons of loading coils, for
instance.)
As to my earlier comment about "fence posts", I meant wire fencing
using in some rural areas which was used as a telephone conductor.
Obviously not the best.

And it was a real bitch troubleshooting when someone left a gate open.

TerryS

[Don Bowey]

Post by Terry

Post by David Lesher

Post by Don Bowey
I haven't read the entire thread so this may not be new to you.

...

Post by Don Bowey
This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.

My query stems from the dim neurons of my brane. It was about the issue
of getting enough power down that long R-C filter [...called the local
loop...] to power the multiple ringers in a house.
It had nothing to do with saving CO ring suppy power. Before
SubCycle's became SOP, She used to have big honking 48VDC->120V 20Hz
motor-generators in the larger CO's and various uglyness in smaller
ones. Not even a anal beancounter could find that load midst a large
panel or step installation.
There was some very clever aspect of the whole design of the ringer
magnetics that solved the issue. THAT's what I'm interested in learning
about.

Well, the standard bell must have been tuned to 20hz, thats just good power
economics, and it would not respond to transients, or 60hz pickup. With a
standard 2 on 4 off cycle, I bet that one third of the bells all rang at the
same time. Just to keep the load on the generator constant. Note that a
party line would have bells tuned to different frequencies.
TerryS

Not all party lines used tuned ringers. I don't think any significant
number of Bell offices did. Party lines were served by using combinations
of putting the ring on either the Tip or Ring wire to ground, along with a
positive or negative DC voltage. This is called Divided Ringing. If you
had a four party line you only heard your ring. If it was eight party, you
heard your ring code and one other.

[Don Bowey]

Post by David Lesher

Post by Don Bowey
I haven't read the entire thread so this may not be new to you.

...

Post by Don Bowey
This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.

My query stems from the dim neurons of my brane. It was about the issue
of getting enough power down that long R-C filter [...called the local
loop...] to power the multiple ringers in a house.

The answer is, in part, the ringer has a relatively high impedance such that
each REN=1 ringer will draw only 3 mA. And, of course, the low frequency of
the ring frequency is the other part.

Post by David Lesher
It had nothing to do with saving CO ring suppy power. Before
SubCycle's became SOP, She used to have big honking 48VDC->120V 20Hz
motor-generators in the larger CO's and various uglyness in smaller
ones. Not even a anal beancounter could find that load midst a large
panel or step installation.
There was some very clever aspect of the whole design of the ringer
magnetics that solved the issue. THAT's what I'm interested in learning
about.

[Terry]

Post by Don Bowey

Post by David Lesher

Post by h***@bbs.cpcn.com

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]

In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer.

....
This is the 6th grade Phun with Science level explanation; one you might
see in what I called "Popular YuckTronics" magazine.
If you look at my origianl query, you can see I was addressing the far
less obvious issue of getting enough power down the far-from-ideal line
to run the ringers. THAT is what I still seek insight into....
[and why I x-posted to s.e.d...]

I haven't read the entire thread so this may not be new to you.
Without knowing more about the particular ringer you have in mind, I can
only generalize.
FCC requirements, and those of the Standard, ANSI T1.401-200? prevail and
provide some insight. My T1.401 copy was issued in 1993, but likely still
valid for this subject.
When a Central Office puts an Alert (the ring signal) on your phone line, it
has both a DC and an AC component.
The DC is typically 52 Volts, but may be higher or lower, but in any case it
has nothing to do with ringing your bell. It is used to determine if your
phone has gone off-hook indicating you answered your phone. This is really a
safety feature so you don't get that loud ring in your ear.
The AC ringing voltage, nominally 105 VAC, rings the bell. At the time my
copy of the Standard was issued there were 13 possible ringers, itemized by
their intended use frequency (between 16.6 Hz. and 66.6 Hz.), still in use
in the USA.
This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.
I hope this helps.
Don

Any idea of why these specific frequencies >

TerryS

[Don Bowey]

Post by Terry

Post by Don Bowey

Post by David Lesher

Post by h***@bbs.cpcn.com

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]

In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer.

....
This is the 6th grade Phun with Science level explanation; one you might
see in what I called "Popular YuckTronics" magazine.
If you look at my origianl query, you can see I was addressing the far
less obvious issue of getting enough power down the far-from-ideal line
to run the ringers. THAT is what I still seek insight into....
[and why I x-posted to s.e.d...]

I haven't read the entire thread so this may not be new to you.
Without knowing more about the particular ringer you have in mind, I can
only generalize.
FCC requirements, and those of the Standard, ANSI T1.401-200? prevail and
provide some insight. My T1.401 copy was issued in 1993, but likely still
valid for this subject.
When a Central Office puts an Alert (the ring signal) on your phone line, it
has both a DC and an AC component.
The DC is typically 52 Volts, but may be higher or lower, but in any case it
has nothing to do with ringing your bell. It is used to determine if your
phone has gone off-hook indicating you answered your phone. This is really a
safety feature so you don't get that loud ring in your ear.
The AC ringing voltage, nominally 105 VAC, rings the bell. At the time my
copy of the Standard was issued there were 13 possible ringers, itemized by
their intended use frequency (between 16.6 Hz. and 66.6 Hz.), still in use
in the USA.
This part applies to a phone having an AC determined REN of 1: If you have
a Bell System type phone/bell, just to get you in the ballpark, you can
assume 20 Hz. Typically the ringer impedance (including the DC blocking
capacitor) will be about 40,000 Ohms, so ring current will be about 3 mA.
As you can see, it won't take much of a husky ring supply.
I hope this helps.
Don

Any idea of why these specific frequencies >
TerryS

No, except there is an advantage in keeping the frequencies low; less line
loss. And 13 is a huge number of options. I don't know how many
frequencies might have been used in a particular type of office; it wasn't
important to the Standard. There had been two other frequencies, but they
were retired by the time the Standard was written.

[Curtis R Anderson]

Post by h***@bbs.cpcn.com
But later people no longer had to rent their phones and could buy
them. A way was needed to avoid overloading the line, so a "ringer
equivalence" was set up. The plain Bell System 500 set was defined as
1.0 . As it turned out, most newer sets had a lower rating, my
Comdial 2500 with a mechanical ringer is 0.8, electronic ringers are
even less.

An old Kellogg 2554 I had in the '80s had a ringer equivalence of 0.7B.

Post by h***@bbs.cpcn.com
Would anyone know what the ringer equivalence be of older phones, such
as a 300 set or the Bell Chime?

With something like a Zaptel card and Asterisk, would there be a way to
measure what the FXS module is sending to the set? In time, I can
measure my 302 set that way.

[T]

Post by h***@bbs.cpcn.com

Post by David Lesher
Years ago, I read an explanation of why telco ringers are what they are.
where the 2565 lives on forever...]

In the very beginning they realized there was a need to signal the
caller and the operator. Thus the ringer. To power the ringer, the
subscriber had a hand crank. I believe originally the frequency was
16 Hz, then later to 20 Hz. These were known as local battery
systems. The subscriber's telephone set had batteries in it. The
advtg of these systems was that worked well on lousy loops, either
very long ones or ones made of poor conductors (like fence posts).
On today's common battery systems, where the talking current is
supplied by the phone company, the ringer must be AC to be separate
and cut out, via the capacitor, so it won't shunt the line and appear
off hook. (Others can explain this better.)
In the old the days the Bell System knew how many extensions a
subscriber how since it provided them. I could ensure adequate ringer
power was available. Very few people had more than five extensions on
a single line.
But later people no longer had to rent their phones and could buy
them. A way was needed to avoid overloading the line, so a "ringer
equivalence" was set up. The plain Bell System 500 set was defined as
1.0 . As it turned out, most newer sets had a lower rating, my
Comdial 2500 with a mechanical ringer is 0.8, electronic ringers are
even less.
Would anyone know what the ringer equivalence be of older phones, such
as a 300 set or the Bell Chime?
I don't know if this system is used on all-new PBXs that have digital
phones, perhaps they use a different signalling technique altogether.
Obviously VOIP isn't shooting 20Hz 90VAC over the Internet.
Someone mentioned Morris IL, yes, they had to develop a low powered
tone ringer. But it didn't work out very well and was not continued.
ESS was developed to handle standard ringing. How it's done today
with digital switches I don't know.

And here's a shot of the Morris 500 set. I note the horn style speaker
and the vents cut into the side of the case.

http://www.flickr.com/photo_zoom.gne?id=1176853218&size=l