The URA-232 is a video, audio and uni-directional RS-232 over UTP receiver. The receiver is located at a distance from the AV/RS-232 source and connected to a compatible UTP sender or extender. The URA-232 has a digital input configurable as "Contact" or "Voltage". User defined serial strings can be sent depending on the state of the digital input and also remotely from a compatible UVA-232-4 or UVA-232-8 sender or via serial command. Using the remote capability, you can have URA-232 and URA-232-XT units daisy chained and talk to all the connected devices serially with each sending the same or completely different serial strings.
In a typical application the RS-232 port on the unit is used for transmit only to issue power commands to connected displays (the RS-232 RX pin is used for programming the URA-232 for remote trigger operation). There are 3 ways to issue commands please see Serial Command Modes Demystified
for further information.