digital station loop errors

[adamandamy]

I have a customer with a BCM400 V4.0. Recently they're running into a problem where the phones (T7316e) reset themselves at random and cause digital loop errors in the alarm log.
It's not all the phones at the same time, just some random subset of phones and it's just like if you were to unplug the phone from the wall and plug it back in again. Needless to say this is very frustrating to the customer.
I have to say that this started occuring during some construction and the operation of an arc welder. But the problems don't seem to coincide with the actual operation of the welder.
I was originally blaming the welder but since it also occurs when there's no welding, I need a new clue. Has anyone run into this problem before?

 

[wiredent]

What is the configuration of the BCM 400?

How many DNs to you have active / available?

 

[adamandamy]

It's a 400 with expansion cabinet. Bottom slot is a DTM. Next is a 4X16 and the top 2 are DSM 32s. One slot in expansion is occupied with a DSM 32. About 100 active DNs. As near as we can tell all of the effected phones so far are ports that are contained in the Main system and not the expansion. Not sure that's significant because the vast majority of the phones are in the main system.

Thanks

 

[wiredent]

Have you checked the extensions to see if they are on the same module?

I had a problem similar that ended up being the 4x16.

 

[adamandamy]

the problem occurs over at least 2 different modules. All in the main system cabinet. I'm thinking it's a power issue with the arc welder somehow screwing up the power regulation to the BCM that somehow screws up the power to the sets or generating EMI on the station cable causing random set shutdowns. Anyone know if I can confirm this somehow. THere are no alarms being generated that point to power issues other than digital station loop errors.
I've had the customer reboot the box to see what happens. I have my fingers crossed.

 

[adamandamy]

Apparently there was a Nortel bulletin that talked to this problem. ID# 2003007338. I'm not convinced this is the root cause of my problems, but it's a good starting point. I've replaced 1 DSM32 and we'll see what happens.

 

[TLDuk]

I currently have a similar problem with a 3.6 system what i have found is if i unplug the T7316e terminal and replace it with a M7100 the M7100 consistently goes slow ie if you type digits in very quickly, it will miss number or get stuck, this only happens on extension that previously had T7316e that are resetting...

My system is on CAT5e if i take the phone to the patch panel it works perfectly, so i run i Fluke test on the CAT5e and it complained about noise on the line but still passed...

I tested another nearby port it passed but did not complain about noise on the line, i moved the extn there and it worked perfectly..