A T1 is a point-to-point, high capacity phone and data line that connects a business customer with a telecom provider or an internet service provider. T1s have been around for decades and were created for organizations that needed a line with more bandwidth. T1 lines are divided into 24 channels, each of which is capable of transmitting data at 64 Kbps, for a combined transmission speed of 1.544 Mbps. In contrast, a single analog phone line has one channel and a 64 Kbps transmission speed.
The configuration of a T1 line is flexible. The entire capacity can be used for phone or just for data, or the channels can be divided up so that one T1 supports both phone and data. Additionally, the channels can all be merged together in order to take advantage of the 1.544 Mbps throughput.
T1s are steadily being replaced by DSL and cable. Although T1 lines are very reliable, they're also much more expensive than these other options.
