LV2 PC to Mocom Adapter
The PC to Mocom Adapter (PMA) is a small box which interfaces a PC's parallel port and sound card output to the Mocom radios we use for the 2m emergency uplink system. We run a java app which calls dtmfdial to make dtmf tones and which toggles a bit on the parallel port to key up the Mocom.
Here's the schematic:
Here's the Front view of the adapter (the DB-25 plugs right into a PC parallel port):
Here's the rear view of the adapter (the power plug is 12V from the Mocom's battery and the RJ-11 carries the sound (2 wires) and the "push to talk" switch which is turned on using a MOSFET):
And here's the inside guts:
