Call Forward
The device supports Call Deflection (ETS-300-207-1) for Euro ISDN and QSIG (ETSI TS 102 393) for Network and User sides, which provides IP-ISDN interworking of call forwarding (call diversion) when the device receives a SIP 302 response.
Call forward performed by the SIP side: Upon receipt of a Facility message with Call Rerouting IE from the PSTN, the device initiates a SIP transfer process by sending a SIP 302 (including the Call Rerouting destination number) to the IP in response to the remote SIP entity's INVITE message. The device then responds with a Disconnect message to the PSTN side.
Call forward performed by the PSTN side: When the device sends the INVITE message to the remote SIP entity and receives a SIP 302 response, the device sends a Facility message with the same IE mentioned above to the PSTN, and waits for the PSTN side to disconnect the call. This is configured using the CallReroutingMode.
| ● | When call forward is initiated, the device sends a SIP 302 response with a contact that contains the phone number from the Call Forward table (see Configuring Call Forward) and its corresponding IP address from the routing table (or when a proxy is used, the proxy’s IP address). |
| ● | For receiving call forward, the device handles SIP 3xx responses for redirecting calls with a new contact. |