Johnathan Corgan wrote: > I hope this isn't embarrasingly simple. I think so. > I need to have a PIC port drive a signal, referenced to ground, at 5V or > -5V, either sourcing or sinking up to 20 ma (per bit, 8 bits). > Furthermore, it would be prudent, but not necessarily required, to have > galvanic isolation between the input and output, as the output may be > subject to static electricity. Somebody already suggested MAX232 (or similar), but if you've already got the +/- power supplies, why not a plain old 1488 driver? Four per chip, and they're pretty rugged. -- Dave Tweed -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body