E1 channels problem

Unanswered Question
Apr 22nd, 2007

Hi all ,

I have E1 line & ATM technology in my call center setup.I know that E1 has 32 channels & its BW is 2.048 Mb but my problem is my output after ATM is 1724 Kbps & i want to know that how this 1724 comes , what is the calculation for this 1724 Kbps. (Is there any thing like compression)

Come ON guys...awaiting for your valuable reply.

I have this problem too.
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gmarogi Wed, 05/02/2007 - 05:12

The E1 interface operates at 2.048 Mbps over coax cables.

The E1 transmission link consists of 32 transmission channels (0-31), each of which is 64 Kbits/sec. The overall transmission rate is 2.048 Mbits/sec. Channels 0 and 16 are reserved for transmission management, while all other channels are used for payload. The payload bandwidth is thus 1.920 Mbits/sec. Since ATM uses 48 out of the possible 53 bytes for payload transmission, the net transmission rate becomes 1.738 Mbits/sec.

Channel 0 carries F3-OAM information, signals loss of frame or synchronization, and is responsible for transferring FERF and LOC messages. Channel 16 is reserved for signalling.

mohammedmahmoud Wed, 05/02/2007 - 05:26


This is simply because ATM uses Cells, the cell is 53bytes, with 48 payload and 5 header, accordingly the net payload or throughput from the E1 is 48 bytes of every 53 bytes, if you do the math you'll find that it gets out around 1.7 mbps.

HTH, please rate if it does help,

Mohammed Mahmoud.

nileshKahale Sat, 06/30/2007 - 05:33

Hi mohammedmahmoud ,

Really Thanks for this , it comes 48*53=2544+5=2549 that means 2.048Mb


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