Unusual serial comunication

[MegaADY]

Hello all ! I start this thread for the third time ... Until now I got only ambiguous answers to my problem because I was not too clear with my setup. Now I attached a schematic here with my setup.
Basically, I have two devices. A master device and a slave device independent from each other. The master device powers with 5 V the slave device.
Now, I put a pic inside the master device ( PIC 2 ) and a pic inside slave device ( PIC 1 ) . I want PIC 1 to send few bytes from time to time to PIC 2 at maximum 1200 baud ( 600 or less is ok too ... ) using the power line. Melanie gave me an ideea in this thread.

http://www.picbasic.co.uk/forum/show...hlight=megaady

The problem is that it is a little bit different from my setup. Can anyone help me ? I am stuck with this and I can not figure it out. I would like to use some simple hardware addons, like Melanie's not power line controllers or stuff like this. Thank you very much !