USB to RJ-45 console cable?

Discussion:

(too old to reply)

unknown

2005-04-03 22:41:26 UTC

Hi All,

I know have read numerous threads on Google goups and cannot
come up with an answer on this one.

I have already read and seen that there are cables/adapters that
go from USB to DB-9. That would allow you to connect your standard
serial console cable as you normall would. I am trying to find a way
to eliminate this.

I would like to buy/make a cable that will have a USB connector on
one end and an RJ-45 on the other. I'm not sure if it is as easy as
cutting off a connector on the usb and just terminating the RX/TX/GND
like you can do with a serial cable (DB-9).

I know there may be some issues with going from USB to rs-232
signaling and I could always build some kind of breakout box
in the middle.

Any thought?????

- Jay

Someone

2005-04-04 01:44:13 UTC

Permalink

Post by unknown
I would like to buy/make a cable that will have a USB connector on
one end and an RJ-45 on the other. I'm not sure if it is as easy as
cutting off a connector on the usb and just terminating the RX/TX/GND
like you can do with a serial cable (DB-9).

USB is 4-conductor plus the shell, and the only things I've seen ready-made
are USB ethernet adapters, which include electronics you don't want.
But any custom shop can make one for you, or you could do it yourself as
you describe.

Oh, here's something: http://www.datapro.net/products/USE-150.html

Dale Farmer

2005-04-04 02:14:01 UTC

Permalink

Post by unknown
Hi All,
I know have read numerous threads on Google goups and cannot
come up with an answer on this one.
I have already read and seen that there are cables/adapters that
go from USB to DB-9. That would allow you to connect your standard
serial console cable as you normall would. I am trying to find a way
to eliminate this.
I would like to buy/make a cable that will have a USB connector on
one end and an RJ-45 on the other. I'm not sure if it is as easy as
cutting off a connector on the usb and just terminating the RX/TX/GND
like you can do with a serial cable (DB-9).
I know there may be some issues with going from USB to rs-232
signaling and I could always build some kind of breakout box
in the middle.
Any thought?????
- Jay

What are you trying to do with this adapter? There are USB to
8pin modular adapters already used in the security system market,
allowing cheap USB cameras to feed to a PC rather than much more
expensive dedicated security type cameras and video logging systems.
These devices are also being used in the AV world for extending
USB mice to the lectern from the PC running the power point presentation
back at the tech table.
As for USB to a RS 232 serial port, then you will need some active
electronics. I don't know if someone makes one, but I expect there
is one out there.
--Dale

Dmitri(Cabling-Design.com)

2005-04-04 14:42:47 UTC

Permalink

A USB device will not talk directly to an RS-232 without use of a special
converter that would buffer the data, format is differently and send over
the other interface. There are devices out there (check out ads in pretty
much any industrial/hobby electronics-related publication) with USB on one
end and RS-232 on the other, within $75-$100 range. You will have to worry
about the actual connections yourself: most I've seen have either straight
headers or screw terminals.

Speaking of USB-to-RJ45 though: APC's UPSes are connected to PCs with
exactly the same cable. This is not to say that it has anything to do with
conversions; there is non done in the cable as the UPS is looking for a
USB signal, but the point is: if you grab a hold of a cheap 350VA unit
that does not have to get hooked up to a PC (like, a one used to protect a
KSU or some other device without USB), you can borrow a nice 4ft factory
made cable with USB connector on one end and 8P8C (often referred to as
RJ45) on the other. Completely proprietary pinout, but what do you care?
You'll have to come up with your own anyways, so why not to use APCs?

Good luck!
--
Dmitri Abaimov, RCDD
http://www.cabling-design.com
Cabling Forum, color codes, pinouts and other useful resources for
premises cabling users and pros
http://www.cabling-design.com/homecabling
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Robert Bonomi

2005-04-04 15:49:08 UTC

Permalink

No it is *not* that simple. You need the 'goodies' that are in the cable
you won't buy.

You cannot build one for the price you can buy a USB-RS-232 adapter
cable for.

just go buy one.

You _can_ just cut off the DB-9 end of such a cable, and replace it
with an "appropriately wired" RJ-45. Assuming the wires in the cable
are small enough guage to _fit_ in a RJ connector. You -do- need to
worry about more than just TX/RX/GND. CTS, RTS, DCD, DSR, and DTR need
to be considered, too.

Post by unknown
I know there may be some issues with going from USB to rs-232
signaling and I could always build some kind of breakout box
in the middle.
Any thought?????
- Jay

James

2013-08-01 17:42:59 UTC

Permalink

Post by unknown

RX/TX/GND

Post by unknown
like you can do with a serial cable (DB-9).

Okay, I think I may have missed something here, but I stumbled across this
post looking for (I believe) the same thing the OP was, but then I see links
to USB/DB9 converters and someone talking about power supplies, so if I've
missed something, I apologize. I was hoping to find a way to skip the USB/DB9
adapters and build a straight forward cable which would allow connecting
between a USB port on my laptop/tablet and a console port on a piece of
equipment like a cisco switch. I don't know what all that would require
(hence why I am looking), but I've got cables, crimpers and RJ-45s. "Beware
programmers who carry screw drivers." If I am understanding
anything/everything/something then the OP was looking for the same and the
general consensus among those who seem to be talking about the same thing is
that it is worth it to buy the cable since a direct USB/RJ-45 conversion isn't
possible without some extra components. Did I get it or miss something here?

--
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John Levine

2013-08-01 18:52:00 UTC

Permalink

Post by James
that it is worth it to buy the cable since a direct USB/RJ-45 conversion isn't
possible without some extra components. Did I get it or miss something here?

You got it. The internal hardware and software protocol for USB is
very different from that for a serial port.

If you search online for usb to serial converter, you can find lots of them under $10.

--
Regards,
John Levine, ***@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. http://jl.ly

Doug McIntyre

2013-08-02 04:51:16 UTC

Permalink

Post by James

Post by unknown

RX/TX/GND

Post by unknown
like you can do with a serial cable (DB-9).

I assume the mention of serial cable means that both of you are
looking for a USB to serial with RJ-45 connector on it. As opposed to
something like a USB to ethernet with an RJ-45 connector on it.

I don't think you could find a USB to serial dongle that doesn't have
the electronics actually located in the DE9 head end of the device.
If you cut that off, you'd end up with a broken USB plug.

While, USB to TTL line level serial cables are pretty popular (ie. see
line from FTDI), especially for the electronics hobbist that routinely
can use them, USB to RS-232 level serial cables are pretty rare, but
they do exist.

I bought a batch of them directly from Shenzhen. They use SiLabs chips
and the electronics, with RS-232 line level converter chip all exist
in the USB plug end of the cable. There is no dongle in the middle,
just a USB plug with an RJ-45 on the other end.

I've been toying around with buying a bigger batch and selling them on
eBay or something. :-)

There seems to be like minded people that want them.
They work against all my Cisco/Juniper/Sun/Fortinet gear.

Mikey B.

2005-04-05 00:59:19 UTC

Permalink

Try this link, I have one of these, it works great!!

http://sewelldirect.com/USBtoSerial.asp?kid=-75846804&match_type=search&keyword_test=usb%20to%20serial

TerryS

2005-04-05 07:44:26 UTC

Permalink

Bought one for my new laptop that has no serial port. Imagine my dismay when
I found the thing was not programmable as DCE or DTE. Still have to carry
around null modem cables and gender adapters. And the laptop ! A giant, too
large and too heavy, have not yet found an equipment room with enough clear
space to set it up. Ends up on the floor.

TerryS

Post by Mikey B.
Try this link, I have one of these, it works great!!
http://sewelldirect.com/USBtoSerial.asp?kid=-75846804&match_type=search&keyword_test=usb%20to%20serial