[Asterisk-Users] Difference between E1 and PRI

[Peter Svensson]

On Wed, 23 Feb 2005, Eric Bishop wrote:

> I have seen the term E1 and PRI used interchangably when referring to
> a voice service with 30B channels and 1 D channel. Are they just
> different terms for the same thing or is there some technical
> difference. Even Newton's telco dictonary seemed a bit fuzzy on this
> topic. I have seen it said the PRi is a protocol that runs on top of
> E1. Is this true?

E1 is a serial line capable of 2048 Mbit. After channelization you have 31
usable 64 kbit channels. One channel (number 16) is used for signalling
(even when using CAS) and the remaining 30 channels are available for
voice.

When you run ISDN PRI over the E1 the ISDN signalling is placed in the 
signalling channel of the E1.

Peter