Dds definition

Also known as Digital Data Service and Subrate Digital Loop (SRDL). An end-to-end, fully digital, dedicated data service available in point-to-point and point-to-multipoint configurations. In either configuration, a designated headend system (Front-End Processor [FEP] or communications server) controls all access to the network through a process of polling. The DDS generally supports line rates of 2400 bps, 4800 bps, 9600 bps, 19.2 kbps, 56 kbps or 64 kbps, and digital carrier rates of 1.544 Mbps (T1) and 2.048 Mbps (E-1).The DDS signals actually are carried inside T-carrier or E-carrier channels in the backbone carrier networks. DDS was introduced by AT&T in 1974 and is now provided by most incumbent carriers, worldwide, under a variety of names. Fractional E-1 and T1 local loops are often tariffed as DDS circuits. See also backbone, carrier, digital, DUV, E-1, E-carrier, FDX, four-wire circuit, HDX, headend, point-to-multipoint, point-to-point, simplex, T1, and T-carrier.