GSM data quality - what does 16khz pulse duration mean?

[c***@hotmail.com]

I have a "Fixed Wireless Terminal model GW1000BL" which is a device
that takes a SIM chip and supplies dial tone back to any RJ11 device
plugged into it. I am trying to use this terminal as a means to
communicate alarm signals from my home alarm to the central station.
I can get low speed pulse signals (called 4+2 in alarm speak) to go
through - but when I try a higher rate protocol called Contact ID -
the transmission fails. I dont know if the issue is a frequency
limitation in the cell system design (Rogers Canada GSM) or perhaps a
setting on the Fixed Wireless Terminal that could be adjusted to
improve the throughput.

The owners manual for the terminal talks of parameter settings that
cen be changed - but they are all unfamiliar to me. The ones that
seem like they might be of interest include:

ISD Call (Enable/Disable)
Loop Interruption
PR Outgoing Call (Enable/Disable)
16 khz Outgoing Call (Enable/Disable)
16khz Pulse Duration
Dial Time Out
16khz default value
16khz table

Would anyone out there know if any of the above parameters might
improve the data transmission rate for the terminal?

Thanks, Cindy

[s***@gmail.com]

Looks like you and I have the same device (I presume this was an eBay
purchase). I have a similar problem. I have a Rogers Pay-as-you-go
SIM card installed in the unit, I can place and recieve calls. I am
using the device to control a remote power controller that picks up
after a few rings and utilizes touch-tone for control. I cannot
reliably send touch tones from a landline to the GSM gateway.

The touch tones aren't making it very clearly to the device I have
connected to the Fixed Wireless Terminal. I'm going to see what I can
dig up to improve quality, if I find something I'll write back - if
you find anything, please let me know.

The manual is absolutely terrible - I have no idea what some of the
acronyms are - and I'm good with acronyms. Also - it sounds like the
machine is British or something (the dial tone) - would be nice to
change it to north american.

Best of luck

Post by c***@hotmail.com
I have a "Fixed Wireless Terminal model GW1000BL" which is a device
that takes a SIM chip and supplies dial tone back to any RJ11 device
plugged into it. I am trying to use this terminal as a means to
communicate alarm signals from my home alarm to the central station.
I can get low speed pulse signals (called 4+2 in alarm speak) to go
through - but when I try a higher rate protocol called Contact ID -
the transmission fails. I dont know if the issue is a frequency
limitation in the cell system design (Rogers Canada GSM) or perhaps a
setting on the Fixed Wireless Terminal that could be adjusted to
improve the throughput.
The owners manual for the terminal talks of parameter settings that
cen be changed - but they are all unfamiliar to me. The ones that
ISD Call (Enable/Disable)
Loop Interruption
PR Outgoing Call (Enable/Disable)
16 khz Outgoing Call (Enable/Disable)
16khz Pulse Duration
Dial Time Out
16khz default value
16khz table
Would anyone out there know if any of the above parameters might
improve the data transmission rate for the terminal?
Thanks, Cindy

[Jack Adams]

Here's an observation. Wireless both TDMA and CDMA Radio encoding
schemes don't handle sinusoids (what Touch Tones really are) very well.
They all perform some sort (ACELP encoding is typical) of voice
compression on the audio signal. It's pretty good for voice, enabling
reasonable voice phoneme construction, but fails miserably for things
like transmitting Touch Tones (or DTMF).
To make a long story short, there's nothing much you can do.

Post by c***@hotmail.com
I have a "Fixed Wireless Terminal model GW1000BL" which is a device
that takes a SIM chip and supplies dial tone back to any RJ11 device
plugged into it. I am trying to use this terminal as a means to
communicate alarm signals from my home alarm to the central station.
I can get low speed pulse signals (called 4+2 in alarm speak) to go
through - but when I try a higher rate protocol called Contact ID -
the transmission fails. I dont know if the issue is a frequency
limitation in the cell system design (Rogers Canada GSM) or perhaps a
setting on the Fixed Wireless Terminal that could be adjusted to
improve the throughput.
The owners manual for the terminal talks of parameter settings that
cen be changed - but they are all unfamiliar to me. The ones that
ISD Call (Enable/Disable)
Loop Interruption
PR Outgoing Call (Enable/Disable)
16 khz Outgoing Call (Enable/Disable)
16khz Pulse Duration
Dial Time Out
16khz default value
16khz table
Would anyone out there know if any of the above parameters might
improve the data transmission rate for the terminal?
Thanks, Cindy

[Terry]

Here's an observation. Wireless both TDMA and CDMA Radio encoding schemes
don't handle sinusoids (what Touch Tones really are) very well.
They all perform some sort (ACELP encoding is typical) of voice
compression on the audio signal. It's pretty good for voice, enabling
reasonable voice phoneme construction, but fails miserably for things
like transmitting Touch Tones (or DTMF).
To make a long story short, there's nothing much you can do.

So when I call by voice mail, put in password, dial 1 for this, 2 for that
and 3 for the other thing, I am not touch toning something ? It is all
digital ?

TerryS

[Jack Adams]

The answer to that is yes and no. Yes, the terminating end
(Your favorite IVR) is receiving "real" DTMF tones. Even though
your local "sidetone" sounds like real touch tones, that is not
what is being transmitted over the Radio Access Network. What is
being sent from your mobile handset is a digital signal that will
be interpreted by the MSC into real touch tones. Handset digits
dialed do not travel as analog (sinusoids) from the mobile handset.

Post by Terry

Here's an observation. Wireless both TDMA and CDMA Radio encoding schemes
don't handle sinusoids (what Touch Tones really are) very well.
They all perform some sort (ACELP encoding is typical) of voice
compression on the audio signal. It's pretty good for voice, enabling
reasonable voice phoneme construction, but fails miserably for things
like transmitting Touch Tones (or DTMF).
To make a long story short, there's nothing much you can do.

So when I call by voice mail, put in password, dial 1 for this, 2 for that
and 3 for the other thing, I am not touch toning something ? It is all
digital ?
TerryS

[s***@gmail.com]

Yes - thank you for that information, I wasn't being clear enough in
my first post. I am aware that most cellular enabled devices re-
generate the DTMF signalling at the remote end, as the touch tones are
transfered out-of-voice band. I know a couple of cellular phones I've
owned in the past had options on how to transmit the DTMF as voice
traffic or as command traffic. That is what I was looking for on the
box I own as it does *try* to do something, but it's not very good at
it. I heard a perfect echo back of the touch tone I entered when
monitoring on the handset. They are fixed length DTMF bursts, no
matter how short or long my keystroke is. It's just not making it
across properly I presume. I've tried Landline to GSM Gateway and GSM
phone to GSM gateway - same results in both cases unfortunately. Yes,
I think I'm stuck. Is anyone interested in my GSM gateway? It's
really nice, but the touch tones are working for my application. I
paid $200 US for it just recently, happy to get rid of it for $150
US. Everything is in perfect condition - otherwise I'll find another
use some where for it.

Interestingly enough, when I call my office via the GSM gateway, the
touch tones are properly signalling my PBX. I'm able to dial-
extensions and access voicemail. The particular product I intended to
use with the gateway, doesn't seem to handle it so well. It's a
remote power switch that let's me control up to 8 AC electrical
outlets.

-Shaun