E1

This term seems to have caused much grief. When people hear "E" they think of the drug Ecstasy. I came across this again last night. They have it ingrained in their hearing. I was really unaware of this usage until I came to Sydney.

I work in telecommunications. According to the International Telecommunications Union, a branch of the UN, the term E1 is part of a sequence E1, E2, E3 and E4. An E1 is a transmission link with a speed of 2048 KBit/s ±50 bit/s. In the old world of the 60's and 70's the E1 was set up to carry 30 or 31 voice channels between telephone exchanges. Nowadays it can carry data and many more voice channels when used with voice compression technology such as voip. An E2 four times the speed of and E1, and E3 four times and E2 and so on.

This is all spelled out quite clearly in the standard G.703 and G.704.