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Receiver volume cuts off on IP phones

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rconn

Instructor
Mar 19, 2002
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Hi All,

I have customer who has reported for a long time that they could not hear at times. I have the BCM50 5.0 fully patched. The problem is with IP telephones at both the main site and at the remote site (no problem with digital phones). When they are talking on an outside call and there is other noise nearby such as another phone ringing or someone talking the receiver volume cuts way down and they can't hear the caller. I can duplicate the problem by blowing into the transmitter while off hook with dialtone.

If I go off hook with internal dialtone and blow into the transmitter there is no problem, as in no loss of dialtone volume. It is only when talking on an outside call using the analog lines. Most of the telephones are not a problem as they are in a normal office environment with no other nearby noise. The two IP phones at the customer service desk is the problem. It can very busy and noisy at times with the other phone ringing and customers talking with the other customer service rep.

The remote site uses all IP phones and there are 2 IP phones at the BCM location. They are using 1140 telephones. I have the same results with my BCM50 6.0 using 11xx and 2xxx telephones on analog lines (never noticed before). It much less noticeable with the SIP trunks on my system. The customer does not have SIP trunks.

I am hoping someone can shed some light on this.

Rob
 
This sounds like the echo canceller is "kicking in". To configure it, go to IP Telephony - Media Gateway. You should find three options there: disabled, enabled and enabled with NLP (non-linear processing). First, I would try to disable it to make sure this setting indeed changes the behavior. Then I'd try the other two options to find out which one provides the best results.
 
Nice call ucxguy.

That did make a difference on my system and I will stop by the customer later this week. I had originally turned the setting on with NLP because of the terrible latency with the original off site link. The NLP helped with the long latency. The latency has been improved since then and maybe we can live without the NLP.

I will let you know.

Thanks Rob
 
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