If you are not interested in high Baud rates, I had good success with
Philips NE5050 Power
Line Modem IC. I am not sure if this is still available but they have
another that is (TDA5051).

The NE5050 worked well at 1200 Baud and provided bi-directional
communications.
The system was interfaced to the phone line and you could ring home and
switch the heaters on etc.

Link for data on TDA5051 http://www.semiconductors.philips.com/pip/tda5051_2

Best Regards

David Huisman

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu