This article explains how to connect a registration-based Trunk (user/SIP ID and password instead of IP Authentification) for inbound calls to Impact PBX. As an example, we are using the German provider SipGate with its Sipgate Basic Trunk. This process can vary for other providers and needs to be tested individually. Screenshots can differ from future versions.
In this example:
SIP ID: 23456789 (customer account number)
DID: 0241444555666 (phone number, not needed for config in this case)
Domain/Proxy: sipgate.de
To setup Trunks/Gateways, you will need to have Superadmin access to the Impact PBX.
Instructions
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Setup the Gateway
Go to "Gateways" and click "+", then fill in the data as shown above. Provide a descriptive name for the gateway. Enter the SIP-ID "23456789" in Username and From User and provide the password. Enter the domain "sipgate.de" in From Domain and Proxy. Leave all other settings as they are and make sure the Context is "public" and Profile "external". Register and Enabled must be "true of course. Then click "Save".
2. Setup the Inbound Routing
Go to Dialplan > Destinations. Click "+" to add a new destination. Make sure the Type is "Inbound" as shown above.
Important note: Sipgate do not send the phone number/DID in SIP Invites (unlike some providers), e.g. <did>@sipgate.de. They send the customer account number (SIP-ID). In our example: 23456789@sipgate.de. Therefore, the field Destination needs to contain the SIP-ID: 23456789 (or the phone number). If you are not sure, make a test call and check the SIP messages arriving in the PBX to see what the provider is sending.
In Caller ID Name and Caller ID Number are not important. This merely determines what you see on an incoming call.
In Actions you determine, where an incoming call should be routed to. In this example it will be extension 1004. You can select any inbound destination in the PBX, like extensions, voicemails, ring groups, queues, time conditions etc. Other settings can be selected as required, like call recording. It is always good to provide a short description. Click "Save". You will then see the new destination in the list.
3. Check the Inbound Routes
Go to Dialplan > Inbound Routes and click on the Destination you have just created. It should look as pictured above. Advanced users can add more conditions and actions here for every inbound call, for example require a PIN etc.
Set up is now complete. Calls coming into the phone number/DID 0241444555666 will get routed to extension 1004, or the inbound destination selected.
Important: It is crucial to know what your Trunk Provider sends in the SIP Invite messages. In the case of Sipgate they don't send the phone number/DID in the SIP Invites (as probably a lot of providers do), e.g. <did>@sipgate.de. They are sending the customer account number (SIP-ID). In our example: 23456789@sipgate.de. Therefore the field Destination need to contain the SIP-ID: 23456789 (otherwise the phone number). If you are not sure, make a test call and check the SIP messages arriving in the PBX or ask your provider. If the destination field contains the wrong value, then the inbound call hits the Impact PBX, but it doesn't know where to route it. This usually results in a 404 error message, destination not found.