Transmission Level 1(A U.S. telephone standard for a transmission facility at digital signal level 1 (DS1) with 1.544 megabits per second in North America and 2.048 megabits per second in Europe. The bit rate is the equivalent bandwidth of approximately twenty-four 56-kilobits-per-second lines. A T1 circuit is capable of serving a minimum of 48 modems at 28.8 kilobits per second or 96 modems at 14.4 kilobits per second. T1 circuits are also used for voice telephone connections. A single T1 line carries 24 telephone connections with 24 telephone numbers. When it is used for voice transmission, a T1 connection must be split into 24 separate circuits)
