Noise on trunk lines

[avgindyguy]

We have had this problem before but we cannot remember what the exact problem was. We have 6 ISDN circuits provided by MCI that route calls to us. We are having intermittent static problems on calls. Thought we would get lucky and find just one bad circuit however so far we have heard static on 2 of them. But not all B-channels on the circuit, very intermittent. These two circuits have 24 B channels only, D-channels are on two other circuits. Sync source was using these two circuits so I changed it to two different ones hoping to clear the problem. No such luck. Before I start screaming at MCI, what else could possibly cause this problem? Keep in mind that this is only one our trunk groups, we have others that are configured the same way and contain up to 8 circuits from MCI. Any help would be appreciated.

 

[avgindyguy]

Quick update. My bad. These two circuits with noise do have the D-channels on them. So 23B + 1 D on each. Strange thought that we are not hearing static on any of the other circuits that use these D-channels and that the problem is intermittent even on these two circuits

 

[tkinney]

Intermittant noise is such a pain! I have SBC and last month I had problems that ended up with a problem out in the field between our building and the co. Another time they replaced a circuit and yet another time we had 2 bad cards at the co end. Possible that you may have a few bad lines out of the 23 in those circuits that calls are hitting on an intermittant basis, we still have pots lines so I'm not up on the ISDN but the reason we had intermittant is that calls would hit a good trunk member line then the bad etc. I was able to do a list meas outage-trunk today, yesterday etc. to see which member was bad on my last problem, this helped isolate the bad member in the trunk at least, not sure if you can do this with an ISDN circuit. In other words my bet is that your problem belongs to the carrier and not the switch end at least it's always been the carrier for noise on my end....

 

[orypecos]

The T-1 line has all of the members on one pair of wires, so to have one or two members having static, with no problem on other lines, indicates not a bad wire, but a problem where the t-1 is broken into individual circuits. This can happen at the Channel service unit, out in the network, or on the PBX circuit card. The PBX circuit cards rarely fail, so I would look at the Channel Service Unit and the network.

 

[1a22ip]

I aggree with orypecos.

I would try to swap the DS1 cards on the local end. If the problem remains the issue is with the Telco (Most likely). If the problem moves with the card then it's the card.

ED

1a2 to ip I seen it all

 

[ph0neguy]

I agree with the previous posts, 99% of the time it is your provider. If you run the list measurements ds1 log "board" command you should see all zeros. If you don't you're recieving errors. Those fields are all what you are recieving. Test the board, test board "board" and see if you have any tests that fail. The ones you're concerned with are tests 138-146. If you're failing tests 145 you may have a line coding issue. See if any of this info helps