You can turn on Disable Call Waiting so active calls are not interrupted by incoming calls. You can enable this feature during a call and it will take effect right away. The calls will appear as Missed Calls in History. Any new incoming calls ring busy (to the caller) or go straight to voice mail if you have this service.
To disable call waiting:
- Go to the Settings tab on the resource panel.
- Go to Preferences - Incoming Call.
- Turn on Disable Call Waiting.
Disable Call Waiting is enabled.