[Rack] Modem over VoIP Experimentation

[Jonathan Lassoff]

I'm experimenting with running data over VoIP (SIP/RTP) in order to
try and get the Tandy acoustic coupler working with the rotary
payphone.

In the process, I hooked up a 28.8 Supra modem of mine to ops -- it's
on ttyS4 if you want to futz around with it.

So far, I'm having trouble getting data to/from dial-up BBSes so far.
It'll detect a carrier and connect, but I'm not seeing any prompts.

Cheers,
ojf