Introduction to Data Communications
30c. STDM - Statistical Time Division Multiplexing

30c. STDM - Statistical Time Division Multiplexing

Statistical Time Division Multiplexing uses intelligent devices capable of identifying when a terminal is idle. They allocate time only to lines when required. This means that more lines can be connected to a transmission medium as this device statistically compensates for normal idle time in data communication lines. Newer STDM units provide additional capabilities such as data compression, line priority, mixed speed lines, host port sharing, network port control, automatic speed detection and much more.

31. Telecommunication Multiplexing

Telecommunication multiplexing is used between switching offices on Interoffice trunks and Intertoll trunks. The Telcos (telecommunication companies such as Bell Canada, AGT, BC-Tel, etc..) share communication facilities which can be either FDM or TDM. A communication path can change in mid-stream from FDM to TDM and back again depending on where or whose communication facility is being used.