PRI static only heard by external callers ?

[bcuz789]

Avaya G450, CM 5.2.1, 9630 phones used in office.

One of our locations has an issue where all outside callers that come in on the Telus PRI hear a bunch of static (but the internal employees don't hear any static). Started about a month ago. Static was heard for a few days, then the circuit went fully down. Telus bounced the circuit to get it to come back in service but the static was still heard. First time supporting a Canadian location and have called in dozens of trouble tickets in the States with AT&T. Has always been a carrier issue, sometimes have had to press them a bunch to finally find the problem. With this first Telus issue, they are adamant everything they are responsible for is testing error free. They apparently even changed the smartjack card in our server room (they came onsite, but the people there weren't watching, so they don't know exactly what was changed).

Anyways, it was working just fine for years before this and no one made any programming changes on the Avaya gateway. Anyone ever seen it be a weird issue with the Avaya equipment (need to change PRI slot, etc)?

Tests & Troubleshooting:
Internal to External- static heard by the far end caller, crystal clear internally
External to Internal- static heard by the far end caller, crystal clear internally
Ruling out network/voip: static still heard by external side when using an analog polycom phone via the analog gateway module.
Internal voip to voip - clear
Internal to External independent gateway/remote site via extension dialing over WAN trunk - clear

Troubleshooting:
Full graceful shutdown of gateway and S8300C processor card and power plug removal
Reseated T1 card
Tried a different T1 card
Swapped out ethernet cable in server room connecting from smart jack to T1 card. Even tried the Avaya official T1 shielded cable...no change.
Confirmed gateway is clocking off the T1 card
Only a few errors sometimes seen with the ds1 measurement test. Nothing crazy in the double digits/hundreds/thousands that I've seen with other circuit errors in the past.
Have not yet tried: re-configuring trunk to use card in another empty slot on the G450.
Just today the onsite assistant does say the smartjack connection jack itself is pretty wobbly..possible issue?

Telus troubleshooting:
Alleged replacement of their smartjack card. Note: when they did this work, calls DID come through crystal clear for one day. Then the static started again the next day.
They brought a PBX emulator and connected at the smartjack and are adamant they are only seeing errors coming in from the customer side to the smartjack (so either the avaya gateway or the ethernet cable, which we've replaced the cable AND tried the Avaya T1 cable).

Running out of things to try/replace and still wrapping my head around how only the external callers hear static, yet the internal side is clean/clear.

Thank you all for reading and any suggestions.

 

[dialtonebone]

Is your G450 grounded properly, per the documentation?
What does that gateways synchronization look like?
Do a clear ds1 measurements on the various stats collected and see if the numbers increment up. If they do, then you've got trouble with your PRI or your equipment. Isolate now using a loop back jack to see if the errors go up on one side or the other. This ia DS1 so the errors should be 0. 100% of the time zero. Any errors in the list meas ds1 command demands attention before going any further.

 

[AvayaTier3]

ds1 crossover cable off of your mm710B to Telco Provider interface. Smart Jack, Telco dmarc in same room as pbx?

Any cabling should be for t1 with shielded xmit and shielded receive pairs. Should not run through house cable to another floor to get to Telco dmarc that is on another floor, etc.

A great teacher, does not provide answers, but methods to teach others "How and where to find the answers"

bsh

45 years Bell, AT&T, Lucent, Avaya
Tier 3 for 35 years and counting
[URL unfurl="true"]http://bshtele.com[/url]

 

[Definity75]

We had this same issue with inbound calls from cells. Nothing on our end was causing the issue. I opened a ticket with our service provider.
They had to go to all the CO [Central Offices} and re-seat all the DSX Trunk cards, which seemed to fix the issue. Since, I'm going on a month and a half without any static on the line.

In Short, call your service provider.

 

[bcuz789]

Thanks everyone..having extra looks at this is much appreciated. A few answers/clarifications:

* I do need to get someone onsite to check grounding. Nothing has changed in years but understand it needs to be checked.
* Gateway sync timing is set to clock off the T1 card/circuit.
* Only a couple errors (1's and 2's) in the ds1 measurements test in the last 24 hours. But every single call, the external caller hears static, while the internal user hears it just fine. I've had measurement tests in the hundreds/thousands of errors with circuit troubles in other offices in the past.
* I just placed 5 test calls to a number that goes straight to voicemail. Heard static on all 5 calls, but the ds1 measurements Current Interval errors have not incremented and are still 0. Does that tell/prove anything?
* Smartjack/dmarc is in the same room as the PBX. Only one 10ft Cat 6 cable between dmarc and PBX. We tried a different Cat 6 cable. Then we also bought and tried the Avaya shielded T1 cable but no change...still static heard by every external caller even with that cable.

 

[joe2938]

Put in another service call and have them verify with a t-bird or firebird tester that all calls are static free once isolated from the pbx, if they are then the issue would have to be on your side. Make sure you are there on site to verify the testing of the circuit if possible.

 

[dialtonebone]

Just to reiterate, 1 or 2 errors is still "a lot" on a DS1. DS1 should be perfectly free from errors. Having thousands on another circuit with no problem doesn't mean everything is good, it just means you couldn't notice it.