We ran into a very strange issue that we cannot rationalize and would like some feedback on what might be causing our issue.
We have a UCM 7.1 deployment with a 2811 (12.4.12) voice gateway (running H.323), 79xx SCCP handsets and a VG224 (SCCP). For reasons beyond our control the 2811 is configured in its own Region and the stations (79xx & VG224) are in a different Region. These devices are physically in the same location and don't really need regional policies defined but we are not in a position to change this configuration.
When we configure the inter-region codec policy on UCM to G.729 all stations ring but T.38 fax traffic doesn't work (which is to be expected). To address the T.38 transport requirement we changed the inter-region policy to G.711. When we use G.711 all traffic to the VG224 works properly (inbound/outbound) and T.38 traffic runs without a problem but our 79xx get a fast-busy when trying to make outgoing calls (inbound rings the phone but doesn't connect).
We are trying to figure out why we are having problems with 79xx sets when using a G.711 inter-region codec policy when we don't have a problem with our ports on the VG224 in the same configuration.