Re: TRS-80 model 100 Modem Cable
  By: Jamie Schnaitter to All on Sat Jan 17 2009 22:11:26

 > Does anyone have instructions to make a phone/modem cable for a TRS-80 model
 > 100? i kinda get the jist of it, but any instructions (.txt or .html or .pdf
 > great but a plain old message works) would be great.
 > 

There's a pinout of the modem connector here:

http://digilander.libero.it/rar2k/TRS80/Trs80-100-connectors.html

about midway down the page.

From what I can tell, you should be able to just patch pin 3 of the DIN
connector to ring (red) on the RJ-11, and pin 7 to tip (green) if you just
want to be able to plug it into a phone jack and make calls.

For the sake of putting it in a message, the pinout is supposedly this:

 8   7
3  6  1
 5 2 4

1 - TL - Conventional telephone unit
2 - GND - Logic ground
3 - RxMD - Direct connection to phone line (ring)
4 - RxMC - Acoustic coupler microphone connection
5 - TxMC - Acoustic coupler speaker connection
6 - VDD - Not sure what voltage, doesn't matter in your case
7 - TxMD - Direct connection to phone line (tip)
8 - RP - "Ringing Pulse"

I'm not entirely sure what pin 8 is for, but more than likely it has to do
with your Model 100 detecting an incoming call, or possibly it's the mate of
pin 1 to which you'd connect your conventional telephone if you were doing a
passthru.

If you want suggestions or info on how to test / build this adapter, just
ask.

dm
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