T1 – T3 Carrier System

• T1 = 24 – 64kbps Channels

• Each of the 24 DS0 (Digital Signal 0) channels are able to carry digitally encoded voice band telephone signals or data

• All 24 channels combined form a DS1 with a 1.544 Mbps Transmission Rate

• T2 = 96 – 64kbps Channels

• T3 = 672 – 64kbps Channels

• Developed by Bell Labs

• Used in the United States and Japan