Trigger cable: parallel port out and BNC out to ActiveTwo in. Connect stimulus computer parallel trigger output port (Presentation, E-Prime, etc) AND a BNC cable to ActiveTwo trigger input port. Parallel port DB25M pins 2-9 connect to ActiveTwo DB37M pins 1-8 (bits 0-7), and DB25M pin 25 connects to DB37M pin 37 (ground). BNC center (signal) connects to ActiveTwo DB37M pin 9, and BNC surround connects to ActiveTwo DB37M pin 37 (ground). By inference, BNC surround ALSO connects to parallel port DB25M pin 25 (ground).