One of my PIC projects needs a simple multiplexed network system bus
for connecting 3 or 4 switching and instrumemtaton units to a control
panel. Data must flow both ways through either a coax or a twisted pair.
Data rate is about 5kbps and error detection or correction is needed.
I'm sending commands to turn relays on and off from the control panel to
the relay boxes and receiving instrumentation data and relay states
(whether they are on or off) at the control panel frome the relay boxes.
I've looked at CAN 2.0, seems overkill and expensive; J1850 (SAE), also
seems too complicated; NMEA 0183 (marine standard0; only one way
communications. I may just make something up but don't like to reinvent
the wheel. Thanks.

Dan Mulally
dmulally@silver.sdsmt.edu