CGB MAX-232 9pin serial port on computer +5V-----------+---+ | | 16 = | |+ | | |~~~~~~~~| | 16 2 | | | < Pin 4------|12 13|------3 < > Sout-------|11 14|------2 > | | +--|4 1|--+ +| | | |+ = | | = | | | | +--|5 3|--+ | | |__15__6_| | | | = | |+ gnd-----------+---+--------5 (4) caps @10uF Note polarity I *believe* this was done by Ken Kaarvik