CS1000E DN as Trunk

[fallenangel1]

I was not told about it initially but later on, client told me that they are using 2 of my DNs as Trunks to another PBX (pretty small and locally made). Now, I know this might not be Nortel issue, yet, they are getting their trunk ring after 5 bells. If it was the case on my side, I would have tried changing my RGV Values (as some friends suggested me here and I did it).

Is there any suggestion that can make my client out of trouble, without indulging second PBX (since there is no support available for that one)????

Go For It Even If It's Impossible !