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A digital telecommunications system
developed by Bell Labs in the 1960s. The most commonly used types of
T-carrier connection are T1 and T3 lines. T1 lines, which typically carry
data at1.5mbps ( although speeds of 2mbps are possible), are commonly used
by isps to supply corporate bandwidth; 45mbps T3 lines are
also in widespread use. T-carrier systems can use many kinds of transmission
media, including twisted pair copper, coaxial cable, fiber optic
and even microwave.
In Europe a roughly parallel e-carrier
system is used in which an E1 line, which carries data at 2.048mbps, is
equivalent to an American T1.Thereafter the capacity of e-carrier lines is
measured in straight multiples of the E1 capacity, so an E2 line has a
capacity of 4.096mbps, and so on. |
