nobody@acsu.buffalo.edu (11/17/89)
Came across a question I didn't know today so I'm now asking the Net.
Does anyone know what signals run across the cable running from a
modem to a wall jack? In my case I have 6 wires, I know that 2 are
transmission lines. Can some tell me what each wire is for?
The complete problem is I need to know which line carries a
signal when the line goes Off-hook. A friend added a modem to his
computer at the office and the phone line is part of a PBX. The
problem is he is only using the two transmission wires so when he uses
the modem the light for that line doesn't lite on the phones in the
office. I need to figure out which is the third or even fourth wire
needed to tie into the PBX so we can get the lite on the phones to
work.
Thanks for any help you can provide.
John Cook
[Moderator's Note: I think you are looking for the pair which gives
A/A1 supervision. Many (most) modems have a dip switch setting which
provides for this. Set the switch one way for a single line phone, set
it the other way if you want to illuminate the line key at some other
station on a multi-instrument line. PT]