On Mon, 31 Aug 2009 09:57:33 -0700 (PDT), "icabjeff" said: > I'm connecting the PIC output from a > 9pin > out port on the e block mulprogrammer though a quad opto-coupler to an > I-PAC > keyboard encoder. Hi Jeff, There's some lingo there that I don't get. So I looked at your schematic, and it doesn't make complete sense either, but since you didn't specify pin numbers or part numbers it's hard to tell. Maybe you used AC input optocouplers, but if not, maybe you have the input polarity backward on the optocoupler. Please post another diagram with pin numbers and part numbers. BTW, this is more [EE] than [PIC] but hopefully it'll get there soon, and there's usually no hope trying to change a thread, but if you post another schematic please use [EE] in the subject. Thanks. Cheerful regards, Bob -- http://www.fastmail.fm - The professional email service -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist