Grandstream’s GXW4000 series of gateways offer a ton of features at an affordable price point. They are trusted and deployed by some of the world's largest service providers. The GXW4004 is a 4-port FXS gateway, with 10/100 Mbps ethernet and router. It supports up to 4 SIP accounts.
Update to the latest firmware for your GXW4004 before connecting to our service. You can download the current production release from the link above. Once downloaded, you'll navigate to "Advanced Settings" and click the "Upload from Local Directory" button. Select the file you downloaded from Grandstream's website, and then click "Apply". Once this has completed, your device will reboot. You can then move on to the steps below.
Select "Profile 1" from the primary menu, and configure the following options for your SIP Profile:
Primary SIP Server: sip.t38fax.com:5080 help
Outbound Proxy: sip.t38fax.com:5080 help
NAT Traversal: Keep-Alive
Scroll down and configure the following options:
Allow Incoming Packets from SIP Proxy Only: Yes
Finally, configure the following T.38 specific options further down the screen:
Fax Mode: T.38
Fax Tone Detection Mode: Callee (Added as of version 22.214.171.124)
Select "FXS Ports" from the primary menu, and configure the following options for your SIP Registration. Be sure to Save & Apply all settings (May Require a Reboot):
SIP User ID: SIP Username help
Authenticate ID: SIP Usernamehelp
Authenticate Password: SIP Password help
Finally, configure your fax machine to work properly with your Power-T.38 SIP Trunk. Review our Recommended Fax Machine Settings for details.