Path: utzoo!telecom-request
Date: Wed, 15 May 91 14:24:19 PDT
From: David Ptasnik <davep@u.washington.edu>
Newsgroups: comp.dcom.telecom
Subject: Re: Adding a Modem to System 85 Set 
Message-ID: <telecom11.364.3@eecs.nwu.edu>
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> Jeff, it is not possiable to add a modem to your new set. The "other"
> jack is for add on equipment such as a speaker phone (I have one of
> those sets in my office and I work on Sys 85).  In order to use your
> digital phone line, you would need a data module on your set AND the
> other end!!!  Then you would use Sys 85 to tranmit in its own language
> (digital) between the two.

I think you'll find that there is a work-around to this problem.  One
of the things that can be plugged into the "other" jack (at least on
the analog sets) is a General Purpose Adapter.  You can plug in a
modem (certainly up to 2400 baud), a fax machine, any single line type
device, into the GPA (it has a standard RJ-14 receptacle).  The GPA
has a three position switch on the front: Basic (grabs on outgoing
line when the single line device goes off hook), Auto (in conjunction
with programming, this sends ring voltage to the single line outlet
and allows faxes, answering machines and modems to answer calls), and
Join (interrupts an existing voice call and bridges the call to the
single line outlet on the GPA).

Thus you can have data connectivity thru the system 85 using a modem,
but not directly from an RS-232 port on your PC.  The system 85 treats
the modem transmission just like a voice, converting it into it's own
language for transmission through the system, and returning your voice
or modem transmission to it's original form at the destination of the
call (another telephone on the system, or a line port going out of the
system).  It is possible on the Merlin( the system 85's smaller
half-brother) to set the phone up for simultaneous voice and data
calls, establishing two talk paths to the phone.  I forget off the top
of my head if the 85 can do this as well.


davep@u.washington.edu