> > I agree for uni-directional, but how would you do half-duplex? > For anything that works uni-directionaly, can't you just require a software layer to do line turn around or polling to get data in the reverse direction? BillW -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist