(This is a very old post from the original blog)
In Malaysia, E1 is the main type of cable used at Base Transceiver Station (BTS) / Radio Base Station (RBS) in order to carry data (voice/packet) and signalling information.
Why is one E1 = 2.048Mbps?
1 E1 frame = 32 timeslots/channels
1 timeslot = 8 bits (speech/voice rate)
Sampling rate = 8 kHz (Nyquist rate -> 2x bandwidth)
:. E1 data rate = 32 x 8 x 8000 = 2.048Mbps
E1 is European standard while T1 is American standard.