Telecommunication Control Unit
Encyclopedia
A Telecommunication Control Unit was device present in the now outdated mainframes of the past that were attached to a multiplexer
channel. TCUs freed mainframes from handling the data coming in and out of RS-232
ports. The TCU would support multiple terminals, sometimes hundreds. Many of these TCUs could support RS-232 when it was required, although there were other serial interfaces as well.
Multiplexer
In electronics, a multiplexer is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n select lines, which are used to select which input line to send to the output...
channel. TCUs freed mainframes from handling the data coming in and out of RS-232
RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
ports. The TCU would support multiple terminals, sometimes hundreds. Many of these TCUs could support RS-232 when it was required, although there were other serial interfaces as well.