ringing issue from enterprise system using CS1000e as tandem

[Crowtalks]

We have a CS1000e at an EMS location and the 911 dispatch is using an Asterix enterprise system and IP phones that tandems their calls through the CS1000e. The vendor replaced their old servers in Feb with new ones (the old servers had been in place for two years) and is sitting behind an Audiocodes that connects to me via OSIQ PRI and to the Asterix via SIP.

Since they went to the new servers they are having random issue with no ringback tone at times to certain locations. It seems the ringback issue is isolated to certain numbers...apparently some numbers they call do not create this issue. The vendor has been blaming me, or the TELCO CO for all their woes and to date, we have been able to prove that all the other issue were on their switch.

I am under the impression that all IP phones generate their own tones, ie, dial tone, busy tones and ringback tones on command from the controller...does any one have any ideas how I can troubleshoot this, as the vendor is blaming me and the EMS is putting pressure on me for a solution or a way to definitively say it is the vendor?

Thanks, Jim

"If I had known it would turn out like this, I would have become a locksmith" Albert Einstein

NCSS, NCTS, NCTE, CS1000E, Call Pilot
Avaya IP Office
Mitel 3300 Advanced, 5000, SX200, NuPoint, MiCollab, MBG