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New Member

36xx and fractional E1 problem

Hi There,

we've just had a BT Megastream 1 installed and have the a-end with a 3620 with an E1 card, the bend is a 2501. Bt have provided the B-end as 1mb X21 whilst the a end is unbalanced G704 Nx16 over an E1.

At the moment the aend is serial up protocol down, b-end is serial down, protocol down, if I unplug the serial leads from the a-end the b -end goes serial up, protocol down. receonnect the cables and the b-end goes serial down. If I loopback the E1 card the b-end goes serial up and protocol loopback detected. If I loopback the b-end the a-end doesnt detect anything.

This has been driving me mad, any suggestions would be greatly appreciated.

kind regards



Re: 36xx and fractional E1 problem

I would contact BT about this. It looks like the line is still in some loopback or test-mode.

Cisco Employee

Re: 36xx and fractional E1 problem

Ideally you need to start with lhysical layer troubleshooting using hardware loopback test on that E1 line..Here is the link which will help you.

Locate "E1 troubleshooting" part on that page which has useful links.

New Member

Re: 36xx and fractional E1 problem

many thanks,

BT have admmitted its a config problem at the a-end exchange, that was after three days of them saying there was nothing wrong with their stuff.