MICS incoming call ring,no answer/no audio 1

[stech624]

Customer has a Nortel MICS system with 7.1 software , 6 port fiber expansion module, 2 DS trunk modules and 4 ASMs. Eight analog lines are supplied by the LEC via T-1 to an Adtran channel bank. All lines ring to two T7316 phones on ports 101 and 102 and a T7208 on port 111.
There are two aspects to their problem.
Occasionally, sometimes several time in a day, an incoming call will ring at the assigned stations, but when answered there is no one there, i. e., there is no audio in either direction. If the answering party hangs up, the call rings back, but still has no audio. Usually the calling party will hang up and call back and the call can be answered.
On other occasions a caller will complain that they just called and let the phone ring several times but no one answered, although there was no other traffic on the system and the attendents were sitting at their desks.
I have power-cycled the system and the LEC’s channel bank, re-seated all the modules, replaced the DS trunk module in slot 3, then rolled the trunk modules in slots 3 and 4.
The problem seems to occur on all lines but is most often seen, as you would suspect, on the first two lines in the incoming hunt group. All three ringing extensions have experienced the problem.
Anybody got any ideas?

 

[luv2ski]

Test at channel bank minus MICS

Pretty much retired from telecom and now grow and sell perennials from April-November and Ski from Nov-April

 

[stech624]

Thanks much luv2ski, I considered that, but it happens so sporadically it is difficult to catch it when it does. It may go days with no problem, then it starts again. I had it happen one time when I was on site, but I could not make it happen again. I'll try it at the CB and let you know what happens.

 

[curlycord]

Sounds like carrier issue for sure, perhaps their Adtran device....maybe over heating if only happens once in awhile.

The circuit probably rang but the adtran was not able to transfer/convert to the trunk port.

If you have it replaced and still and issue then carrier signal needs to be looked at.

What are the NT #s for the trunk cards in your trunk module?.



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curlycord

http://www.curlycord.com

 

[stech624]

NT7B69AAAC, if my records are up-to-date. I'll check this evening since I was going to do some testing when the phones are quiet. It is a 24 hr. facility.

 

[curlycord]

Cards are ok.



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curlycord

http://www.curlycord.com

 

[stech624]

I was wrong. The cards are NT7B75GA-93 and NT7B75GB-93. Still have not had time to check lines at Adtran.

Thanks

 

[curlycord]

Ok too, it was the NT7B75AAAE I was afraid of as I had issues in the past with it.


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curlycord

http://www.curlycord.com

 

[curlycord]

You should swap both card with each other when on site too, if issue moves to lower lines then bad card.



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curlycord

http://www.curlycord.com

 

[stech624]

Hey guys,
I did all you suggested. I made over 100 test calls one night and answered them at the channel bank and could not duplicate the problem. But the receptionists continued to report isolated incidents. This went on for several days. Tuesday, I got a call reporting a rash of these calls. I was close by and was on site in about 15 minutes. Clipped onto the first line at the channel bank and made two test calls that rang but could not be answered. Problem was with the LEC, not the Nortel. Sometimes you just have to get lucky.

Thanks for all the great help.

 

[allworxguy]

It's never the Norstar.

Marv ccna

http://www.telemarv.ca