The LANCOM VoIP router allows additional phone lines to be used for voice communication as a supplement to your existing ISDN exchange lines. These new lines may be to a SIP PBX connected via VPN, or to a public SIP provider on the Internet. Each time a connection is established, the call router uses pre-determined rules to decide which of the existing lines is to be used for the call.
As an alternative to the automatic selection by the call router, you can direct individual calls to a certain line, for example when you want to call a party purposely via ISDN and not via the SIP PBX at the headquarters. For this purpose, the call router assigns specific code numbers to existing lines, such as "98" for ISDN or "97" for a SIP provider. The targeted call via this line is then initiated with the corresponding identifier:
- The call with "020 123456" is assigned to a corresponding line by the call router, e.g. via the SIP PBX at the headquarters.
- However, the call with "98 020 123456" is made directly via the ISDN connection by the call router.
