Designator for any of several digitally multiplexed telecommunications carrier systems, originally designed to transmit digitized voice signals. The American and Japanese hierarchies are based on multiplexing 24 voice-frequency
channels and multiples thereof. T1 = 1.544 Mb/s (DS1) (24 user channels), T3 = 6.312 Mb/s (DS2) (96 Ch.), T4=44.736 Mb/s (DS3) (672 Ch.), and Etc. (where one channel = the digital equivalent of an analog phoneline POTS.