Digital Signal 1

1 as a trunk (T1, T-1 or DS1) is referred to in the telephony the first multiplex level of the U.S. telephone system with a data rate of 1.544 Mbit / s or 24 ISDN data channels with 64 kbit / s Of the individual data channels, both voice and data traffic are handled. T1 was developed by AT & T in 1957. The specification was adopted in 1968 and applies in Canada and Japan.

A full T1 line can be rented as a leased line ( leased line ), and often served to enterprise connectivity to the Internet via an Internet Service Provider (ISP). Colloquially often spoken of a T -line. A faster alternative to T1 is T3, which is often used for connecting the ISP to a backbone.

The European equivalent of this is the Primary Rate Interface (E1 ) with a data rate of around 2 Mbit / s

The Japanese standard J1 differs from T1 in only a few details.