From the "PBX" tab in Elastix, go to the "Trunks" link. After selecting "Add New Sip Trunk" you need to edit the trunk settings. We suggest making two trunks and naming one, "SIPTRUNKGW1" and the other "SIPTRUNKGW2." The settings on each should be identical, only the name and the gateway you are registering to should change. One should be set to register to gw1.siptrunk.com and the other gw2.siptrunk.com
You may refer to the images below for specific trunk settings, however the peer details are listed here to cut and paste (ensure that you change gw1.siptrunk.com to gw2.siptrunk.com for the second trunk:
username=<ENTER YOUR TRUNK #>
secret=<ENTER YOUR TRUNK PASSWORD>
Once you have finished adding the trunks it's time to set your Outbound Routes. Under the "PBX" tab go to the "Outbound Routes" link, and add a new outbound route. Give the route a descriptive name and add the dial patterns you wish to match (our favorite examples are in the images below).
You may need to change the route position as Elastix has a standard route position which is first. We have deleted that route in our examples, we did not need to change the "Route Position."
Finally, change your "Trunk Sequence" to ensure that your trunk for gw1.siptrunk.com is first (0) and you trunk for gw2.siptrunk.com is second (1).
Save and apply the changes! You should now be able to make outbound calls through sip.us. If you have problems after trying this guide, you can always submit a support ticket using the link at the top-right of the page!