I suspect you could misuse and abuse several different types of transceivers for this application. RS232 / 485 / CAN come to mind. All designed for various noise immunity and tolerance levels. Not suggesting you use the actual protocol, but just the physical link with your data protocol. Personally, I'm fond of CAN. As to a specific part recommendation... MCP2551. -Denny --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .