NOTE: The SBX-AC1200P operates as a wireless extender out of the box. The SIP Passthrough is setup in the primary router that manages the home network. If the SBX-AC1200P is operating as a wireless router, proceed with the instructions below.When using a VoIP phone with the SBX-AC1200P, the SIP Passthrough option in the SBX-AC1200P may need to be enabled in order for that phone to have full functionality. In other situations, it may be recommended by the VoIP phone manufacturer to disable SIP Passthrough. By default, SIP Passthrough is enabled. This document describes how to enable SIP Passthrough in the SBX-AC1200P.
NOTE:Â If it is not known if SIP Passthrough should be enabled or disabled, please contact the VoIP phone manufacturer.
To Enable SIP Passthrough
- Â Connect a Wi-Fi client device, such as a laptop, smart phone or tablet, to the SBX-AC1200P default wireless network.Â
NOTE: The default wireless name and password is located on the back panel of the SBX-AC1200P. Â
 - Launch a web browser, such as Internet Explorer, Firefox, or Safari.  Enter http://192.168.0.1 into the address box, and press the Enter key.  The Login page will appear.
 - On the Login page, enter admin in the Username field.
 - Enter password in the Password field.
 - Click the Login button.  The Home page will appear.
 - Move the mouse-cursor over Advanced on the main menu and click the Options link on the sub-menu. The Advanced - Options page appears.
 - On the Advanced Options page, under the NAT ALG Status section for SIP - Check Enable.
 - Click the Apply button.
