>They say the mind is a terrible thing, and I can attest to that -- >trying all morning to remember what's being used these days in place of the >PC900 opto. for MIDI boards, and I'm drawing a blank. >Any help? 6n137 or 6n138, IIRC. You could doublechek by downloading the schems for one of Paia's MIDI devices. Byron Jacquot