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E1 and channel E1

Can anyone tell me what's different between E1 and channelized E1?


Community Member

Re: E1 and channel E1

Hi Ricky

Found this article a bit informative and please follow and revert in case u have more questions.

Okay a bit clearing about E1:


> E1 is Linespeed 1984 or 2048.


> Unchannelized E1 means clear bandwidth of 2048 unstructured

> channelized e1 means trunk is divided by 32 Timeslots; Timeslot 0 is used for

> syncronization of the other timeslots and cannot be used for data transmissions.

Then you mean unchannelized E1 is clear channel of 2M with no framing

convention of PDH. While channelized E1 is the normal E1 of PDH with

slot 0 for synchronization, and slot 16 for in-band signaling. Then

if I order a channelized E1, I actually get only 30 slots available

for my data, right?

The practical example may be: if I rent a 2M DDN p-t-p connection form

A to B, then I get the _unchannelized_ E1 connection, clear bandwidth,

and low delay. While the 2M connection between LE(local exchange in


A and LE B of a carrier is _channelized_ E1 connection with possible

30 slot in it for 64K voice, right?

What's more, what's fractional E1 mean? Only nx64K(n<32) connection

within a _channelized_ E1?



Community Member

Re: E1 and channel E1

Hi Vatsan,

Can you tell me how do unchannelized E1 used for DATA trasefer without any synchronization of clock; i.e without slot0. Does it mean asynchronous data transfer or it used for special purpose application.

Community Member

Re: E1 and channel E1

Hi Vatsan

thank for your answer.I'm now confusion with ISDN PRI and channelized E1. Are they the same?


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