Hosts use a text-based protocol to communicate with RACE RESULT 4000/5000 Series System's decoders via TCP/IP on port 3601 or via RS232 using a USB-COM-port adapter. By default the RACE RESULT Decoder acts as server, but since protocol version 1.5 a client mode is also available. The default approach for getting passings is pull-based. Since version 1.5 the decoder can automatically push passings to the host as they appear, too.
RACE RESULT Decoder TCP/IP