The inputs on the S4 timer are specific to the program you are using. The 18 channel mode used for time of day timing with the PC is your best choice to find out what is happening. 18 channel mode activates all the channels at once. In program 0 (3 racers on single course) the only way to get a finish pulse is by using the "A" channel DIN "photocell" connector. Likewise the only way to get a finish impulse in Program 1 (dual slalom) is by having each finish line connected to the appropriate "photocell" input. Always check you manual for complete listing of channels and inputs. When in doubt, use program 3. That way you will be able to get start and finish impulses recorded on the paper and you can figure it out. Photocell inputs use the DIN connector. Pin 3 is ground, Pin 2 is pulse, Pin 5 is 6 volts output to power an ALGE cell. You can purchase one of these Din connectors at Radio Shack in 6 pin configuration cat # 274-020. These plugs are plastic but they will get you through.

You can also access all the timing channels using the mc-18 or mc-opto18 for better data protection! This allows you to use banana jacks for all connections to the S4