>...it is unlikely that > requiring the handshake (if that is the case) is just caused by the > hardware: I use the same hardware without any hardware handshake (just 3 > wires, GND, TxD, TxD). So your particular hardware does not insist on hardware handshaking. I've got a Rockwell UART here (R6551AP) that get's its knickers in a knot without handshaking. I believe the original IBM PC RS-232 adapter also required hardware handshaking or the UART would simply not pass data. Both work fine with the magic 6-4 & 7-8 jumpers. I still submit that there are variations in hardware that may or may not require strapping the handshaking before any software can receive or send data through them. Aza D. Oberman -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist