Intermittant Dead Air / One Sided calls

[duffman5000]

Merlin legend system Hybrid/PBX. With no apparent pattern, outbound calls will hear dead silence after dialing. They don't hear a ring or a voice after entering the number. Some of the calls, at least, do complete as people have called back to say they could hear us, but we couldn't hear them.

Figured it may be one bad line in trunk causing it to seem interrmittant, but cannot seem to repeat the problem when selecting individual lines directly from the admin console phone.

Any ideas on usual suspects? It had been reported by several users on different MLX-10 sets.

Thanks!

 

[tdaugirdas]

Have you re-booted the system (cycle off and back on again)? That sometimes resolves a lot of issues. I would also look at the processor error logs for clues.

Tom Daugirdas,
President
STCG, Inc.
stcg.com

 

[duffman5000]

Thanks. Yeah, I'll be power cycling it at the close of business. It's not bad enough to knock everyone off the system during the day.

I experienced the issue first hand and I would get dead air after dialing one number in 703 area code, then hang up and dial number in 410 area code that went through fine, then hang up and try 703 area code again and have the same dead air.

It was odd that when the issue occurred it didn't seem to affect all numbers. Made me think it was a Verizon issue, but they, of course, claim it is not. I guess I won't know until I get to do some more testing this evening.

 

[duffman5000]

Rebooted and had same issue. Took analog phone around to trunk lines to take PBX out of the picture and replicated same issue which convinced Verizon they may actually have a problem on their end.

Basically, the calls get connected but one party hears silence. It also only seems to happen to a certain percentage of calls to certain numbers/area codes so my best guess is that something is wrong in the CO or a verizon switch.

It wouldn't be the first time. Last time, they had crossed our main rollover number with someone's home number so most of our business calls were being sent to some poor guy.

 

[merlinman]

Are your LINES labeled?

IF not, put a unique label on them and then see if the failure follows a particular line or two.

That is a good starting point.

 

[phonesrus]

Sounds like a CO issue, I have seen the problem pop up in older 1A offices that still use Tie Lines to other CO's.
It is a half-duplex condition on the circuit where the circuit board or even the cable pair is bad, since these are 4-wire circuits. You can nail it up by continually calling until you get a failed path then keep the path open and get a carrier tech to run a trace on it. Another option is to get the carrier to look at their switch logs for trunks with high user access but low talk time, it's a "dead" give away.

 

[duffman5000]

Thanks phonesrus. That sounds like the best fit for what is happening.