Time Division Multiplex. An electronic system used for transmitting a number of data channels over a single pair of wires. Used in both signalling and locomotive controls. Found on http://www.scot-rail.co.uk/page/Glossary
Time Division Multiplexing. Time-sharing of a transmission channel by assigning each user a dedicated segment of each transmission cycle. Video Multiplexers in CCTV use TDM techniques to record many signals onto a single tape.
Found on http://www.zoo.co.uk/~z0001325/Glossary.html
Time-division multiplexing. Technique in which information from multiple channels can be allocated bandwidth on a single wire based on preassigned time slots. Bandwidth is allocated to each channel regardless of whether the station has data to transmit. Found on https://www.encyclo.co.uk/local/22803