🚀 go-pugleaf

Those interested in the X-10 system for remote control of home lights
and appliances should take a look at the May/June issue of "Circuit
Cellar Ink".

page 14 - advertisement for X-10's PL513 power line interface module
  This is a new product from X-10.  The PL513 is the size and shape of
  an ordinary lamp module.  It contains a 120 Khz oscillator, a
  zero-crossing detector, power-line interface, and optically isolated
  computer interface.  The idea is that your computer listens for the
  zero crossing and sends enable pulses to the oscillator at the right
  moments.  This can be done in hardware or software.  This allows
  complete flexibility to modify or extend the X-10 protocol.

  The ad promises a 2-way version "later this year".

page 4 - article "Power-Line-Based Computer Control"
  This article blows the lid off the PL513 module.  It gives the schematic
  of the device, recommends hardware interfaces for three common machines,
  and gives software.
 
  A section on X-10 theory, as well as a protocol description, is included.