Core Issue
In the Cisco CallManager 5.1(1), when a call is parked, it cannot be retrieved on any extension.
In addition, when the conference button is hit during a call in order to bring in a third participant, the third participant can be called, but a conference is not established between the three participants when the conference button is hit again. When the conference fails, the Cannot complete conference error message appears and the original called party is dropped from the call, but the second call remains active.
This issue occurs in these IP Phones:
Resolution
In order to resolve this issue, disable the Advertise G.722 Codec Cisco CallManager Enterpise Service Parameter, and reset the device pools that contain these phone types:
This is further documented in Cisco bug ID CSCsi61965.
When the service parameter is enabled, it allows these TNP/third generation Cisco IP Phones to negotiate and use the G.722 codec when calls are within the same region. Because of a lack of support for the codec type, this causes interoperability problem symptoms, such as call disconnects, for these features:
- Ad-hoc Conferencing
- Call Park
Refer to the Enterprise Parameter Changes section of Release Notes for Cisco Unified CallManager Release 5.1(1a) for more information.
