T1   A leased line connection capable of carrying data at a very high speed (as in 1,544,000 bps or 1.544 Mbps). At maximum theoretical capacity, a T1 line could move a megabyte in less than 10 seconds but that is still not enough bandwidth for full-screen, full-motion video (for which you need at least 10,000,000 bps). T1 is the fastest telephone trunk line commonly used to connect networks to the Internet.