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Configure a 3CX PBX v15 Trunk

Intro to 3CX PBX Version 15

3CX is an open standards IP PBX that offers complete Unified Communications, out of the box. Suitable for any business size or industry 3CX can accommodate to your every need; from mobility and status to advanced contact center features and more, at a fraction of the cost.

3CX makes installation, management and maintenance of your PBX so easy that you can effortlessly manage it yourself, whether on an appliance or server at your premise or in the cloud. This article guides you on how to configure this PBX for making and receiving calls over the internet through a next generation carrier like Telnyx!

You'll need to have created a credentials based connection on your Telnyx Mission Control Portal account, assigned this connection to a DID and outbound profile in order to make and receive calls.

Note - You'll need to acquire a license when installing this version of 3CX. You'll be prompted to fill out a form and include your email address so they can verify your email and send you the license key.

3CX PBX Version 15 Prerequisites

  1. Download 3CX v15 - 3CX Version 15 is available to download from here.
  2. Install 3CX - by following the installation guide.
  3. Finally, Configure your Telnyx Mission Control Portal.

You're ready to get started!

3CX PBX v15 Setup Guide

3CX Installation

During the installation process, 3CX will ask you to specify a username and password which will be used to login to the web interface. 3CX automatically detect your pubic IP address. You can then specify if this is a static or dynamic IP. You can configure your 3CX with an FQDN and 3CX will provide you with one - they do this to ensure your FQDN is set to resolve to your Public IP and for generating certificates. You'll then choose your default network adapter and decide whether you want the extensions to use the local IP of your PBX or the FQDn you created. At the end, you'll choose your preferred http/https port numbers which will be used to allow you to access the 3CX web interface via your FQDN or Public IP.

Great you can now login and begin your configuration!

Basic Setup


Specify Extension Length


Specify an Admin Email

Specify an admin email and configure your mail server configuration by specifying a mail provider.


Select Country and Time Zone


Specify a Default Operator Extension


Security - Confirm Countries Calls Can Be Made To


Select a Language

The last sub section is registration and you should fill out your personal details here. 3CX


Confirm Your Network Settings

  • Go to "Settings" -> "Network".
  • "Ports" Tab: make sure your "SIP Port" is set to 5060.
  • "Public IP" Tab: double check your Public IP is correct and that you have selected the proper Network card Interface.
  • Settings --> Click on "Network Settings" --> Public IP tab --> Section : "External IP Configuration".
  • NOTE: Please make sure that connection IP on the portal and Static Public IP is same. You can also use the FQDN for inbound calls and the credentials for outbound calls.

Create Telnyx SIP Trunk

  1. Click on "SIP Trunks" from the navigation menu on the left.
  2. Click "+ Add SIP Trunk" near the top of the screen.
  3. A new pop up will be opened. You need to enter/select all the required details :


  1. After entering the details, Click on OK.
  2. This will open the trunk configuration window:
    • Tabs
    • General
    • DIDs
    • Caller ID
    • Inbound Parameters
    • Outbound Parameters
  3. In the General tab, there are 3 sections to be explained in the following sections:
    • Trunk Details
    • Authentication
    • Route calls to

Trunk Details




Route calls to


  1. Select the "Options" tab

    • For "Require registration for:" select "Do not require".
    • Remove the "GSM-FR" from Assigned Codecs.
    • Click "Apply".
  2. Select the "Outbound Parameters"

    • For "Contact : User Part" in the SIP Field column Select "Custom Field".
    • To allow private calling - "From: Display Name" and "From : User Part", select "Custom Field" but leave the Custom values blank.
    • Click "Apply".


  1. After entering all the details please click on “OK” which is on the top.

    • If all the fields are entered correctly the IP trunk will now be live. We can now proceed to our inbound and outbound rules.


Inbound Rules

  • Click on "Inbound Rules" from the navigation menu on the left.
  • Click on "+Add DID Rule" near the top of the screen.
  • There are 2 sections in this:

    • General
    • Route calls to



Route Calls to


Outbound Rules:

  • Click on "Outbound Rules" from the navigation menu on the left.
  • Click on "+Add" near the top of the screen.
  • There are 3 sections in this :

    • General
    • Apply this rule to these calls
    • Make outbound calls on


Rule Name : You can enter any preferred name


Apply this rule to these calls:


Make outbound calls on:

We need to configure routes in this section. Configure up to 3 routes for calls. The second and third route will be used as backup. For each route, digits can be stripped or added. Strip Digits 0 on Route 1 and Strip Digits 1 digit for remaining 2 routes.


After completing the configuration, click "OK".

That's it, you've now completed the configuration of 3CX V15 IP-PBX Trunk and can now make and receive calls by using Telnyx as your SIP provider!

Additional Resources

Still need help setting up 3CX PBX Version 15? Click the Live Chat icon at your lower right hand corner and start a chat.

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