| Remote site dials | Call router receives | Assigned via | number in use | correct call route | Destination line | |
|---|---|---|---|---|---|---|
| 0 123 555 555 1 | 555 555 1 |
|
11 | ISDN NT |
- The incoming call via the number to the MSNs for the connected ISDN terminal equipment is converted into an internal number by the ISDN mapping table and passed on to the Call Router. The Call Router cannot find a matching entry in the call routing table, but it can find a registered user with the matching internal number. Since the user is an ISDN user, the Call Router directs the call to the ISDN line with the MSN entered for this user, '555 555 1'. The PBX receives the call to '555 555 1' on its external ISDN bus and again determines that this is an external MSN and can channel the call to the corresponding ISDN telephone.