Application background

Analog terminals for emergency calls in the building elevator. When the VoIP gateway loses connection with the SIP server, it needs to use the analog terminal to call the outside line and realize emergency failover and reliability.

Function definition

Use the FXO gateway to provide customers with alternative lines.

When the network from the FXS VoIP gateway to the SIP server is not reachable, the call is automatically sent to the FXO PSTN line for outbound calls, providing a high-reliability guarantee for the customer's voice communication in the elevator.

Option 1: non-FXS/FXO hybrid gateway

Instructions:

The FXS gateway registers to the SIP server through the Internet, and the FXO gateway connects to PSTN.

FXS and FXO gateway in the same local area network

Using the active and standby function of the FXS gateway, when the SIP server is not accessible, the calls will be sent to the FXO gateway.

Configuration

1. On Basic>SIP page of FXS gateway, configure SIP server and High availability (FXO gateway address):

2. On Advanced > SIP page of the FXS gateway, turn off the Re-register on INVITE failure function

3.On Basic>SIP page of the FXO gateway, configure the FXS gateway IP address on the Proxy server:

PS. FXO will only accept calls from this address

4. On Routing > Routing table page of the FXO gateway, add the route as IP X ROUTE FXO ：

Option 2: FXS/FXO hybrid gateway

Instructions:

The VoIP gateway has both FXS and FXO ports.

FXS registers to the SIP server through the Internet, and the FXO ports connect to PSTN.

Using the escape function of the gateway, when the SIP server is not accessible, the calls will be sent to the FXO ports.

Configuration:

1. On Basic>SIP page, configure SIP server

2. On Trunk > Advanced page, enable the PSTN failover function