We have a customer with a SV8100 with a PRI that can't call out on certain channels but it keeps changing. They will call one day and not be able to out on channel 23. We put channel 23 in a different trunk group and they will call again and say that now they can't call out on channel 21. They get a busy signal even if the line isn't busy. We upgraded the software to 11 last week but it's still happening. The carrier says its not them. It's been installed for years and this just started happening.

Test the channels individually. #9 001 etc and make a call. Frankly I have found it's almost always a carrier issue. Check your clocking check what type of PRI it is (usually NI2). Check the cable. Also is this an IAD (VOIP) PRI or a standard PRI?

Hi Coral Tech. Yes we have tested the channels by using the #9 XXX code and have verified that yes indeed we cannot call out on the specific channel. This is a standard PRI and we have it set as a NI2. So unless the carrier changed it, that's what it should be.

Check your programming on that channel to make sure it's in the trunk group and set for DID. Otherwise they have a bad channel somewhere. Pretty cut and plain.