When using HY-TEK with various Photo Finish Systems, Button Timers and Alpha-numeric Scoreboard computers, the two systems are connected with a cable which is either a serial cable or a null modem cable. This cable plugs into a 9 pin male Serial COM port on the HY-TEK computer. Most systems will have either a 9 pin male port connector. Most computers these days do not come with a serial COM port, so you will have to install a USB to Serial Adaptor.
The serial and null modem cables have nine wires in them, but normally only the 2 and the 3 wires connected to the 2 and 3 pins are used. The difference between a straight thru RS232 serial cable and a null modem cable is that the null modem cable makes the 2 and the 3 wires cross (the 2 pin on one end connects to the 3 pin on the other end). Some timing console devices use straight serial cables and some use null modem cables. Computer to computer, such as HY-TEK connecting directly to another computer running an alpha-numeric scoreboard or a photo finish system, always uses null modem cables. If you make your own cable, we recommend wiring pins 2 for send, 3 for receive, and 5 for ground. These cables are generally available at most computer and electronics stores.
See also USB to Serial Adaptor.