Chapter 4 Cisco Call Back
Introducing Cisco Call Back
Call Back Handler
The Call Back Handler resides in the CEF service and receives the called extension and calling extension information when the CallBack softkey is pressed. Cisco CallManager passes this information to the CEF service through the Cisco CTIManager interface.
The Cisco Extended Functions service determines the destination device by using the Cisco CallManager Database Interface. The CEF service opens the line and device by using Cisco CTIManager. When the called line becomes available, the CEF service sends an audio alert (a twinkle sound) and visual notification on the Cisco IP Phone through the Cisco CTIManager and XSI interfaces. Only one Call Back can be active on a Cisco IP Phone. The Call Back Handler keeps this information in memory. Phones and lines get opened through Cisco CTIManager only for a Call
Screen Saver and Call Back Dictionary
The screen saver of the Cisco Extended Functions service reads the XML dictionary files and creates Document Object Model (DOM) objects for all installed locales when the CEF service starts. The system uses these DOM objects for constructing XSI screens that are needed by the Cisco IP Phone.
Redundancy Manager
When multiple Cisco Extended Functions are active within a Cisco CallManager cluster, the redundancy manager uses an algorithm to determine which CEF is active and which is the backup CEF. The Redundancy Manager uses the lowest IP address of the server that is running the CEF service as the active service. The remaining CEF services serve as backup services.
DB Change Notifier
The DB Change Notifier handles all the database change notifications, such as service parameter changes, trace parameter changes, and alarm configuration changes, and reports the changes to the CEF service.
| Cisco CallManager Features and Services Guide |
