A series of digital transmission formats promulgated by the ITU and used outside of North America and Japan.
The basic unit of the E-carrier system is the DS0, which has a transmission rate of 64 Kbps, and is commonly used for one voice circuit. The E1 format consists of 32 DS0 channels, for a total capacity of 2.048 Mbps. E2, E3, E4, and E5 circuits carry multiple E1 channels multiplexed, resulting in transmission rates of up to 565.148 Mbps.
The E-carrier system is similar to, and compatible with, the T-carrier system used in North America, but has higher capacity since it uses out-of-band signaling in contrast to the in-band signaling or bit-robbing used in the T-system.