Last two months issues of Electronics Australia have a line carrier
transmitter/receiver with all the details you'll need.

> ----------
> From:         John Mullan[SMTP:jmullan@VAXXINE.COM]
> Reply To:     pic microcontroller discussion list
> Sent:         Monday, December 15, 1997 6:20 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      X10 devices via PIC16C84
>
> Can anyone point me to some schematics and code for using PIC16C84s
> for X-10 communications.
>
> I would like to build my own modules but don't quite know where to
> begin.  Especially when it comes to pulling the required signal
> frequencies off of the 110V line.
>
> Much appreciated....
>
> John Mullan
>