[GreenKeys] Audio to TTY

[Studio8H]

Cory -

I'm using a couple of Fleisher TU-170 Tuning Units. They have the loop supply built in.
If you have or are going to build a loop supply of your own, I recommend the little AFSK demodulator boards that Eric Volpe put together. 
Audio in, a 9-volt battery to power, and connect it to your loop.
Sweet little board
I'm unable to find the contact info for that. 
Somewhere in the Greeynkeys archives, for sure.

Dan