A European framing specification for the transmission of 32 DS0 (64 kb/s) data streams. By extension, it can also denote the transmission rate required (2.048 Mb/s = 2048 kb/s). Unlike DS1? it is free of BitRobbing.
The E1 channel is divided into 32 timeslots. The first, Timeslot Zero is used for syncronisation between endpoints, and the sixteenth (Timeslot 15) is usually used for signalling information, leaving 30 free DS0 channels.