Digital system 1 or digital signal level 1. Term used to refer to the 1.44 Mbps digital signal carried on a T1 facility. (See also T1)
Digital signal, level 1; 1.544 megabits per second, the North American standard
Digital Service, level 1. Consists of 1.544 Mbps in North America and 2.048 Mbps elsewhere. Also called T-1. Equivalent to twenty-four DS-0 channels.