I am planning a system with a network of PICs. The PICs will be daisy chained together (power and communications) in a standard office environment (fluorescent lights, networked PCs, telephones, HVAC, etc.) The PICs will need to communicate about two bytes (status change of nine LEDs and which PIC sent the event) every 5-10 minutes. Two of the events are pretty important and would need to be acknowledged by the other PICs. Initially, the network will be 300' end to end with 18 PICs. The network could expand to 2000' end to end and about 100-200 PICs. I've got it whittled down to either a CAN or RS-485 (unless someone can convince me another protocol would be better.) Which one do you think is better and why. If I use 18F248/448 do I need to use a transceiver interface such as PCA82C250 or can the PICs connect to the wires directly? Any recommendations for an interface? I was thinking of using the MAXX485 if I went with RS-485. Any other suggestions? TIA Nelson nelson@nosuffering.com www.nosuffering.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics