The Call Manager manages and connects the various subscribers and lines described above with one another. The Call Manager's main task is to determine the correct target subscriber for each call and to select a suitable line for this subscriber. To fulfill this task, the Call Manager mainly uses two table areas:
- The Call Routing table
- The tables of local subscribers
As the Call Manager usually switches between internal and external telephone networks with different number ranges, the Call Manager often has to modify the numbers that are dialed. This is known as number translation.
Note: In the world of VoIP telephony it is possible to call numbers and names, such as "anyone@company.com". Although the following description refers to telephone numbers, this also includes telephone names unless specified otherwise.
The procedure known from internal extension lines is used, whereby connections to external subscribers start with a preceding '0'. The Call Manager processes calls to and from all registered subscribers and lines.
