I have, what I think anyway, a strange problem. We use TA 908 gateways and this is the only site where this problem occurs.
We have a T-1 providing ISDN-PRI service to a site. The gateway is used to connect the PRI to a PBX that can only be configured with SIP trunks. This part works perfectly.
The problem is when the gateway experiences a power failure or the T1 goes out of service, the T1 interface will go to Yellow Alarm. It can be recovered by using CLI to loop up then loop down the network. My saving grace is I have remote access to the gateway so I can quickly get the site up but I shouldn't have to do this.
I opened a case with Adtran and the engineer said that if we put a hard loop on the interface and it goes to up, this eliminates the hardware. We did this loopback including the cable that connects to the NID and it passed.
After much effort, we were able to arrange a vendor meet with the LEC. We showed the technician our trouble. The technician said there is nothing wrong with the circuit because when he connects his T-BERT it goes right to up. He was also kind enough to "back to back" with the gateway. When we did this, the gateway went to UP instead of sticking on Yellow Alarm. I pointed out that if the gateway was bad we should have expected the same result of the interface going to Yellow Alarm but this was brushed aside by, "I can connect my tester to the NID and it comes right up."
I can't disagree with the logic but I am also not 100% convinced there is not an issue upstream from us. I am going to try another gateway just to try and save face with the customer. I don't care if I look dumb, I just want this fixed.
Any ideas? My thinking is that a Yellow Alarm on my interface means something upstream from me is not working. I find it strange that looping then not looping the T1 clears the trouble immediately. I am further encouraged by the fact that connecting the the T1 test set goes right to UP. Since this is a physical layer issue it must (at least in my mind) be a service provider problem.
We have tried a new cable from the gateway to the NID, the NID is about 25 cable feet from the gateway. The entrance terminal for the site is in the same room as the NID and is approximately 25 cable feet away with no splices or obvious defects, and the LEC technician was kind enough to try changing the card in the NID. I was not able to convince them to try the cold spare unfortunately.
My goal is to get this customer to work like every other T1 I have ever worked with. The challenge will be proving to the LEC it is not CPE equipment. I am keeping an open mind though and, as explained earlier, will try a new gateway.
Thank you in advance for your assistance.
Mike Meyer
