T-Carrier Services
Most commonly used dedicated digital circuits in North America
Units of the T-hierarchy
- DS-0 (64 Kbps); Basic unit
- T-1 (a.k.a. DS-1) (1.544 Mbps)
- Allows 24 simultaneous 64 Kbps channels which transport data or voice messages using PCM
- T-2 (6.312 Mbps) multiplexes 4 T-1 circuits
- T-3 (44.376 Mbps); 28 T-1 capacity
- T-4 (274.176 Mbps); 178 T-1 capacity (672 DS-0 channels)
- Fractional T-1, (FT-1) offers a portion of a T-1