Greetings, over the last couple of months we have experienced three T1's dropping at certain times of the night and/or day. We have had the Telco review and do their testing but they keep coming back saying they don't see any issues. We have the vendor who equipment these connect to coming in to test and possibly replace their ACD equipment but I'm wondering if anyone has any thoughts as to what might be causing this problem and how we might be able to pinpoint it?

Thanks
Dan

Hopefully your ACD vendor was able to resolve the issue. If not here are a few steps for you to try, if you haven't already:
1) Replace the cabling from the smartjack(or Mux) to the ACD with known good cabling (swap from other working Ts).
If the problem sticks with these Ts...
2) Swap around the T1 cards in your ACD
If the problem sticks with these T1s...then there is a problem with the carrier. Call the carrier up, tell them the steps you've taken and insist they run a full gamut of tests, with a LEC rep onsite. If these are copper circuits then there is probably a problem in one of the doublers or stations along the way back to the central office.

Oh and if these are by any chance TIE lines, the same thing must be done at the other end (but only do one side at a time).

Thanks Marianne.....

We had the ACD vendor replace the card, cables and paddleboard. Problem continues....

I should make note that this is a third span in an NFAS group. No issues with the Primary or Backup, just this third span.

There are two telco's involved and they both come back saying they are running clean.....in the process of escalting this further up their chain of command.

Our thinking is that this might be due to a configuration or feature set up problem.

One additional option might be to move these to PRI as a last resort if the root cause cannot be found.

I am not fully versed in the T1 architecture, but I have been troubleshooting intermittant connection issues for cable customers. Let me add a few not-so-technical thoughts:

1 - log the time of the losses and see if they coincide with anything else, such as Universal Power Supply charging or backup generator startup. Power surges can do all sorts of weird things.

2 - Check for non-technical causes. For example, does it always happen when it rains?

3 - most intermittancy is caused by physical damage: bad connectors, damaged cable, even poor shielding. A wayward soft-drick machine could be interfering with the data lines.

Hope you get it resolved. Intermittancy is a big pain.

Swap the 2nd T for the 3rd T at the Mux or smart jack. Then wait and see if the error stays on the same place on your ACD or on the same circuit. If it stays on the same circuit then you know the problem is the carriers (or your Mux if you channelize yourself). If the problem stays with the ACD card, then you know you have either a hardware or a settings issue in your ACD. Make sure that if you have any dip switches on your T1 cards that the settings are the same on span 3 as span 2. I've had issues in the past with a vendor swapping out a card and just copying the 'bad card's switch settings, instead of checking to see if they were right.
What brand of ACD is it?

Span has been running clear without any issues since the Telco Larus or Smart card had been swapped out.

Thanks for your suggestions...