Helicopter noise on incoming calls

[acejavelin]

I have a customer with an HX chassis 5000 with about 60 digital phones and a PRI, release 6.0 SP5 PR1... 1 DDM-16, a dual T1/E1, and SLMs in the main cabinet, and DEM-16s in a DEI. Been complaining of "helicopter noise" on incoming calls, but not on outbound or internal calls, only heard internally, outside callers hear nothing unusual and the noise follows a transfer. Cannot be isolated to a single common station card.

No errors on PRI and the carrier has monitored the calls and see no errors and hear no noise on the channels while a bad call is up, leading me to believe it's an internal problem.

I have rebooted the system and the problem continues... Weird part is the DEI, when I did a shutdown and pulled the power then powered back up, the DEI showed nothing, no power light or anything else until 4-5 minutes after the HX chassis was completely back up then it seemed to come to life and worked.

I was leaning towards starting out replacing the PRI card then the processor, but the strange behavior of the DEI makes me wonder if I should start there.

Anyone have some input?


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[DND ON]

Ace,

I've never seen it on the 5000, but it was common on the Inter-Tel IMX phones. It was always on the station side; a bad phone, card, jack or cable. Doesn't mirror what you reported, but I thought that I would throw it out there.

[Tech Electronics]

Acejavelin,

Are you sure that the DEI wasn't just doing a flash upgrade on itself from the system prior to booting?

I would look at the first external common denominator which seems, from your description of events, to be the PRI card. The problem seems to follow the transferred call, the caller doesn't hear it, and it doesn't happen on Internal calls at all.

I would tear down the programming of the PRI and reprogram it from the ground up. If that did not fix it then I would replace the T1/E1/PRI card. If the problem persisted I would look at the PM next.

Thanks,

TE

[acejavelin]

Acejavelin,

Are you sure that the DEI wasn't just doing a flash upgrade on itself from the system prior to booting?

I would look at the first external common denominator which seems, from your description of events, to be the PRI card. The problem seems to follow the transferred call, the caller doesn't hear it, and it doesn't happen on Internal calls at all.

I would tear down the programming of the PRI and reprogram it from the ground up. If that did not fix it then I would replace the T1/E1/PRI card. If the problem persisted I would look at the PM next.

Thanks,

TE

Hmm... I hadn't thought PRI card, my experience with them had been either they work or don't, and it's very rare to see another type of failure. It would be pretty easy to just swap it first and test, then rebuild second. I am going on site early tomorrow morning to upgrade to 6.2 as well, I'll let you know how it goes.

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[acejavelin]

Just a quick update... over the weekend, with several thunderstorms in the area, the helicopter noise turned to bacon frying noise. More digging into the issue found the main number was actually a single analog loop start line outside of the PRI that CFB's to the a DID number, seems to be an issue in the field with that line. Turned over to telco this morning.

[DND ON]

Mmm, bacon!

[sarond]

bacon frying noise

I'm going to use this as my fault descriptions from now on instead of crackling noise (although crackling is still a type of pork  )

[Tech Electronics]

Acejavelin,

I would never have thought of looking for a POTS line CFB to a PRI. The odd thing to me though is that you said the calling party never heard the noise, which is not the case normally with a POTS line.

My next guess would be to look at the DSPs and if they had a PEC on the system to replace it, and if it didn't then replace the Processor Module.

DND ON,

Bacon is good!

Sarond,

Are pork rinds called cracklings there?

Thanks,

TE

[sarond]

Sarond,

Are pork rinds called cracklings there?

Here I was thinking it was called that everywhere 
Yes it is the rind made crispy.