Sorry for the lack of detail. Was hoping I could figure out what the 1220 was or see if it triggered any response. Basically we have 2 sites, Primary (P) and Secondary (S). The P is an S8500. We are using an VPN circuit to connect it to the S which is an S8300. Basically this is setup as two sites UDP'd together. The digital S phones can dial and connect to the P site without incident. However, when we initiate a call from the P site to the S set, we get dead air on the P set and the S set will ring, if ansewred, there is only dead air. When doing the list trace on the P site, we get the ISDN 1220 error. On the remote site, we see it activate the trunk, dial the station, then terminate the trunk.
This hasn't worked before, this is something new we are setting up. The two sites are configured basically the same as far as the sig group and trunk groups.