If you want to remove the G.723.1 codec from the negotiation between your UCMA application and the IP gateway/IP PBX, then it is recommended that you change the configuration on the IP gateway/IP PBX to disable this codec. If this is not possible, you can add the following registration key to the computer that is hosting the UCMA application to disable use of the G.723.1 codec.

Registry key to disable the G.723.1 codec: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Unified Managed Communications API\AudioVideo:DisableG723 = 1

Any other additions, modifications, or deletions to the other values or keys are not supported.