How about adding a half duplex RS485 chip, like a 75176 with transmit control? You could just double up on the same jumpers. Makes for one less circuit in the kludge area. The dual LED idea is great. I know I've had to reverse my indicator circuits on more than one occasion. Bill -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist