Hmmmm. I have pics of the schematic here somewhere.
It took me MONTHS to find the information. Apparently it is illegal to modify phones (FCC), but I don't see why more people don't use cordless phones ($0.50 at a thrift store) for wireless data transformer.
I will look for the schematic.
You have your PC's modem connected to the cordless phone base-station. Your robot needs a modem (has to to de-modulate the signal), and this modem needs to connect to the cordless handset.
This involves cutting open the phone, cutting the ground and signal wires from the earpiece and microphone, soldering leads to those spots, and routing them to the small circuit you have to build. The circuit is powered by a 9-volt battery, and has a standard RJ ??11?? phone cord coming from it. You plug this into the modem on your robot.
until I find the schematic, you'll need to find:
2 "telephone" transformers. I don't know what the specs are, but transformers from: fax machines, modems some phones
will work. They are small, about 3/4" by
2 pots, 2 transformers, 9 volt, and a telephone cord is all you need.
The circuit takes the MIC and EAR signals from the handset and combines them into one signal line.
The pots are used to tune the circuit. You leave the earpiece on while you are tuning, and you can tune out the static.
This setup is very sensitive to noise from electric motors. I do not know how to eliminate the noise. Seperate power supply didn't seem to help.
But it is cheap, and easy.