Digital Signal Level 1 or "DS1" means the 1.544 Mbps first-level signal in the time-division multiplex hierarchy. In the time-division multiplexing hierarchy of the telephone network, DS1 is the initial level of multiplexing.
Digital Signal Level means one of several transmission rates in the time division multiplex hierarchy.
Digital Signal Level 1 (DS-1) means the 1.544 Mbps first level signal in the time division multiplex hierarchy.
Digital Signal Level 0 or "DS0" means the 64 Kbps zero-level signal in the time-division multiplex hierarchy.
Digital Signal Level 3 or "DS3" means the 44.736 Mbps third-level in the time-division multiplex hierarchy. In the time-division multiplexing hierarchy of the telephone network, DS3 is defined as the third level of multiplexing.