> > I am trying to implement several remote keypads with one central master,
> > very similar to a home security system.  Each keypad uses a 4x4 matrix
> > keypad, a 16x2 backlit LCD, 3 diodes, a piezo buzzer, and 2-wire serial
> > communications with the master.

http://www.dontronics.com/dt102.html
may give you some ideas.

Don McKenzie  mailto:don@dontronics.com http://www.dontronics.com

Don's Download Dungeon:   http://www.dontronics.com/download.html
Australian Electronics Ring http://www.dontronics.com/aering.html
Win $500USD Cash. Micro design contest:  http://www.simmstick.com