OnSIP Trunking offers additional reliability by leveraging the OnSIP Hosted PBX platform. (Please note - only SIP trunking is offered, IAX is no longer supported.)
OnSIP Trunking is for customers who are interested in administering their own PBX. For customers interested in letting OnSIP do the PBX administration and handling features such as e911, voice mail, call parking, business hour rules and more, please reference the OnSIP Hosted PBX Getting Started Guide.
The first step is to set up a trunking user via the OnSIP Admin Portal. Since the OnSIP Trunking service is on the OnSIP Hosted PBX platform, you will need to set up an OnSIP Hosted PBX if you don't already have one. If you're an existing PSTN Gateway customer, you can just add a new PBX to your existing account. Be certain to choose the "OnSIP Hosted PBX" type.
You will then need to enable OnSIP Trunking by creating a trunking user. This will create the authentication information for your PBX.
If you are an existing PSTN Gateway customer, you will also need to transfer your existing phone numbers from your PSTN Gateway PBX to your new OnSIP PBX. They will begin ringing to the new PBX the moment that you do this, so make sure you've reconfigured your PBX to use OnSIP Trunking first.