Configure Global SIP Gateway FXO/Line Port Settings

Global Configuration Settings

Refer to Configure Global SIP Gateway FXO/Line Port Settings.

Enable SIP FXO/Line Port Services

Select the Enable SIP FXO/Line Port Services checkbox.

RTP Silence Delay

Enter the RTP silence delay when in call. If there is a continuous RTP silence from the PSTN side, the FXO/Line port terminates the call.

Default is 120 seconds.

SIPGW IP Address

Enter the LAN side IP address to which the SIP gateway binds.

By default, it is set to the class C subnet of the ALG LAN plus 253 (recommended).

For example, if the ALG LAN is 192.168.1.0/24, the default IP address of the SIP gateway is 192.168.1.253. If the default IP address conflicts with another host on the ALG LAN, you can modify the SIP gateway IP address in this field.

Add Dial Out Prefix (To IP network)

Enter a value to prepend to the caller-id received from PSTN to create the FROM field when trunking a call from the PSTN to the IP network. Use digits [0-9].

Enable Priority Calling services

Select the checkbox to enable priority calling services for FXO ports. When priority call services are enabled, any call placed to a priority calling number from any FXS port or LAN-side SIP phone is routed on priority basis to the FXO port and connected.

Note: Enabling Priority Calling Services overrides (or hides) the following settings for individual ports:

• Enable InBound (from PSTN) two-stage dialing

• Forwarded To settings

Note: Priority calling services cannot be configured when WAN Link Redundancy (WLR) is enabled.

Tip: Once priority calling service is enabled, make sure VoIP ALG has a dial plan set for priority calls in SIP trunking rules.

Verify your dial plan settings by clicking the SIP/ALG trunking rules link or choose VoIP > SIP > ALG and refer to Configuring Bandwidth Settings for H.323.

Default Callback Extension

Enter a default callback number to receive callbacks from priority calling service operators after the Priority Call Window has lapsed.

A callback may occur when a user (FXS or IP phone) dials the priority calling number and then hangs up. Ensure that this setting is set to an extension that is always up. This extension must be an FXS port or an extension on the LAN side, preferably the administrator desk extension.

This field is required when Priority Calling Services are enabled.

Note: When priority calling is enabled, the Callback Extension overrides any forwarding number configured for FXO ports.

Priority Call Window (sec)

Enter the amount of time in seconds during which an inbound call from PSTN is forwarded to the last IP caller that made an outbound priority call through that FXO port.

The window starts when an outbound priority call is completed. If the window has lapsed and an inbound call from the PSTN is made, the call is forwarded to the Default Callback Extension instead.

This field is only visible when Priority Calling Services are enabled. You must also configure Priority calling SIP/B2BUA trunking rules. Click the link provided or choose VoIP > SIP > B2BUA and refer to Configuring VoIP SIP B2BUA Trunking.

PSTN Sense Window (sec)

Enter the amount of time that the gateway senses the port to check if the PSTN line is connected to the FXO port and the line is alive. If there is no analog signal during this sensing period, the call is rejected with a “486” error. If value is set to 0 seconds, this feature is disabled.

Enter the delay in milliseconds between dialed digits to the PSTN.