Glossary A–ZLetter R
RS-232
RS-232 is a serial interface through which a control device sends commands to a display and receives responses.
It is old, simple and very common on professional displays, projectors and AV equipment. Typical commands are on, off, select input, volume and status queries.
In screen networks, a player or AV controller uses RS-232 to switch and monitor the display reliably. Unlike HDMI-CEC, the display answers queries, for example with its operating state, temperature or active input. Many displays now also offer the same commands over the network.
Operators should know that each manufacturer has its own command set; the control device must know the commands of the specific model. Cables and plugs differ, and some displays use a jack socket instead of the classic connector. For RS-232 the player needs a matching port or an adapter. Control only works if the display remains reachable for it in standby.