How to connect a 3CX v20 PBX to 2talk

Follow this quick start guide to connect a self-hosted 3CX v20 PBX to 2talk over a registered SIP trunk.

2talk Portal Instructions - Setting Up a Registered SIP Trunk

Account Level Trunking

Select the Pilot Number in the Cloud PBX

Under "Preferences" -> "Register Trunking" tick all 3 options and click "Save"

All voice numbers on the account will automatically latch to the registered pilot

Single Number Register Trunking

Step 1: Select the Pilot/registered number

Under "Outbound Calls" -> "Outbound Trunking" tick the "Enable Outbound Trunking" box.

Step 2: For Each DID you wish to attach to the trunk
Under "Inbound Calls" -> "Forwarding and Trunking" set "Send inbound calls to registered number" to the pilot and tick the "Preserve DDI" box.

3CX Web UI instructions

Allow 2talk Voice IP Range:
From the 3CX Admin Console, select “Advanced” > ”IP Blacklist” > ”Add”.
Set the following configuration:
    "Specify an IP or Range of IP Addresses": "Add a range of IP Addresses"
    "Network Address": "27.111.14.0"
    "Subnet Mask": "24"
    "Action": "Allow"
Select "OK" to save the configuration.

Configuring a registered SIP trunk

Save the template file provided at the bottom of this document.

From the 3CX Admin Console, select “Advanced” > “Templates” > ”Provider Templates” > ”Import Provider”, select the template file and then select ”Import”.

This will redirect you to the configuration page for a new trunk. If experiencing issues with this step then try clearing browser cache or using an alternative browser.

Set the following configuration:
    "Name": a name of your choosing for the trunk.
    "Registrar/Server": the SIP domain you selected on sign up else "sip.2talk.co.nz".
    "Main Trunk Number": pilot number in NSN+0 format, e.g. 0xxxxxxxx.
    "Authentication ID": pilot number in NSN+0 format, e.g. 0xxxxxxxx.
    "Authentication Password": the password assigned to the pilot number in the portal.

Select the "Options" tab and set "Number of sim calls per trunk" to your preference.

Select "Save" to complete trunk configuration. You will be directed to create an outbound rule, set this to your preference following the document linked below. Configuring the outbound rule later will not affect the trunk setup.

A party passthrough

A small number of diverted call scenarios from 3cx do not insert the expected headers. This fails 2talks CLI whitelisting requirements for A party passthrough on a transferred or forwarded call. Overstamping will need to be requested via a support ticket to permit the trunk to do A party passthrough in these scenarios.

Resources

Configuration template file
Configuring outbound calling rules: https://www.3cx.com/docs/manual/outbound-call-routing