This guide will help you get your Digium Gateway up and running with SIP.US. The model used for this configuration is a G100 which fed a T1 connection into an ESI IP phone system. However, this guide should get any Digium G series connected with SIP.US and ready to make/receive calls.
1. One awesome feature of Digium's G series is the ease of setting the networking configuration for your SIP Trunk. In this example we set our Digium to bind itself to port 5061, but by default it binds to 5060. Either one, or something else entirely, is fine! Be sure that you DO NOT enable TCP.
2. Since our G100 was behind NAT we used the "Advanced: NAT Settings" to specify our static external IP so that it could be used correctly for signalling. This may or may not be necessary depending on your situation. If you see a private IP in the SIP.US portal for your registration, you need a setting like the one pictured below.
3. The main trunk configuration is done as a "SIP Endpoint." Be sure to use the password found under "Show Password" in your trunk at SIP.US. Note that we have the "Enable Advanced Options" set to "Yes" but did not have to change any of the advanced options on the endpoint settings. DO NOT enable "Use TCP." Ideally you would create a second endpoint duplicating these settings except that "Hostname" would be gw2.sip.us to provide connectivity to our redundant gateway.
4. Once the SIP Trunk is configured, you can set the specific "Call Settings" for the trunk. We left everything as the defaults.
5. We disabled call codecs except "ULAW" in the Media Settings. Note that SIP.US supports G729 as well as ULAW, but we like to keep things simple.
6. SIP.US needs to receive Country Code + Number for all calls. In North America (not including Mexico) the country code is "1," hence when 10 digits are dialed we have the gateway prepend a 1. The example below also shows how to configure 7 digit dialing for the 352 area code. Modify this to fit your needs.
7. We connected this Digium G100 to an existing IP phone system which expected a T1 connection. The settings below allowed us to replace the existing T1 connection with a connection to our Digium G100. The phone system did not know the difference, and we did not ask it's feelings on the matter.
8. That's it! Go make some calls, and if you have problems, use the link at the top-right of this page to open a support ticket, or email firstname.lastname@example.org