LANCOM routers operating the Voice Call Manager can initiate call forwarding on SIP trunk connections by forwarding the information sent by the PBX to the SIP trunk provider. If this is an ISDN terminal, the partial rerouting (PR) is converted into a "SIP 302 Moved Temporarily" before being transmitted to the provider.
In the SIP lines table, the external call forwarding is configured for each individual SIP trunk line under by enabling the option Call forwarding using SIP 302. With call forwarding enabled, a call-forwarding option initiated from a telephone (ISDN / SIP) is switched directly at the exchange, unless the telephone is part of a call number group or the user is registered multiple times on the LANCOM router.
If the telephone is an ISDN terminal, the partial rerouting is converted by means of the service feature SIP 302 before being transmitted to the provider. The number to which an incoming call should be forwarded is transmitted by the terminal and must be reachable via call routes. The phone number must therefore match the dialing plan in the Voice Call Manager in order for the latter to select the correct line. For this reason, line prefixes have to be specified even though they are removed by the Voice Call Manager once the correct line has been selected.
If the forwarding destination set on the terminal is an internal telephone number, the call forwarding is performed by the Voice Call Manager directly, in which case you have to use the prefix used for internal calls (e.g. **).
