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BCM-50 Clicking on External Calls

BCM-50 Clicking on External Calls

BCM-50 Clicking on External Calls

I would like to think I could handle anything on any of the Nortel Phone Systems, but this one is getting me and I would appreciate any ideas to resolve the issue.

Nortel BCM-50 with two expansion cabinets. Software Version All Phones are Digital T7316e

Issue: Customer reports and I have heard a clicking sound on some External calls. It is at the rate of about every 1.5 seconds. It seems to be present when there is voice activity on the line. It is not heard by the caller, only the user on site. It is intermittent. Sometimes when the clicking is not loud, if you listen very carefully, you can hear it clicking at these same intervals very, very faintly.

Testing: We have had the customer keep logs and have noted the following:

Happens on both incoming and outgoing External calls. Is Intermittent and comes and goes. Some days worse than others. Happens on extensions and lines across the main and expansion cabinet.

We have changed up the Loop Interface setting to Long, Short, PBX Long and Short.

The phone lines are delivered via T-1 thru an Adtran Total Access 616. We have never been able to hear the clicking with test calls coming directly off of the Adtran. The carrier does not see any loss or issues with the T-1 circuit that feeds the Adtran. We have changed out the Adtran and that has not made any difference.

The server room was a bit warm, so we have been running with fans and the door open, no change.

Any help would be appreciated. Thanks

RE: BCM-50 Clicking on External Calls

I had this issue once, I moved lines to the expansion and resolved.
Since you say problem on both main and exp then I might try replacing the main and the MBM, or if 8 lines only then use a GATM8 and leave the main alone.
Maybe the trunk relays are spazzing out.

Maybe it was something else that did the damage, surge?
Try testing the voltages both idle and ring to see if they are too high.

As for temps the damage maybe already done.
If you can hear the fan on a BCM50 then it is not in a suitable location.

For me moving those lines meant it was not a carrier issue thought.


Toronto, Canada

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RE: BCM-50 Clicking on External Calls

Thanks for your thoughts on this issue.

I don't hear the fans running, so I don't think that was the issue.

I have heard clicking through the speakerphones when the system is coming up, but this is an audible clicking in the handset, that seems to be exacerbated when you talk in the handset and extremely faint, really not noticeable most of the time. When it gets going it is disruptive to the call.

My experience is that Nortel is usually consistent and not many intermittent issues. That is why I suspected the provider, but I think that is ruled out now with the Adtran replacement and the fact they don't see any errors or issues with the T-1 span.

It is just off that it is happening on phone extension ports and Trunk ports across cards and cabinets.

I'm not sure how I would deal with the keycode issue. Is there a way to move them to another BCM?

RE: BCM-50 Clicking on External Calls

Yes but cannot be discussed in the forums.


Toronto, Canada

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RE: BCM-50 Clicking on External Calls

Usually, clicking on external calls on a T1 is caused by clocking/timing issue.

Make sure your T1 parameters match the service provider.

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