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.

Instructions for Configuring a 3CX V15 PBX Credentials Trunk


3CX Version 15 is available to download from here.


You can view the installation guide here.

Video Walkthrough

Coming soon! This walkthrough will demonstrate setting up an IP based connection with 3CX. We'll also show you how to assign this connection to a newly purchased DID which will allow you to receive inbound calls. Then we'll walk you through how to assign the connection to an outbound profile such that you can make outbound calls!


For step by step instructions on each of the requirements on the Telnyx Mission Control Portal, please follow this guide.

Once you've configured your Telnyx account, you can now proceed to setup Zoiper following the guide below.



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:
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.


Go to Settings -> Network to confirm your network settings:

  • "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 Telnyx Mission Control Portal and Static Public IP are the 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 : 

Select Country: Worldwide
Select Provider in your Country: Telnyx LLC
Main Trunk No: <Enter the number which you have purchased on your Telnyx Mission Control Portal>

4.  After entering the details, Click on OK.

5.  This will open the trunk configuration window.  

  • Tabs: 

  • General

  • DIDs

  • Caller ID

  • Inbound Parameters

  • Outbound Parameters.

6.  In the General tab, we have 3 sections: 

  • I) Trunk Details 

  • ii) Authentication 

  • iii) Route calls to. 

Trunk Details: 

  • Enter name of Trunk: Telnyx LLC

  • Registrar/Server/Gateway Hostname or IP: sip-anycast1.telnyx.com:5060 or sip.telnyx.com:5060

  • Outbound Proxy: sip.telnyx.com

  • Number of SIM Calls: <set your preferred amount of simultaneous calls>


  • Type of Authentication: Register/Account based

  • Authentication ID (aka SIP user ID): <You need to use the username from the connection which you have created in the Telnyx portal>

  • Authentication Password: <You need to use password from the connection which you have created in the Telnyx portal>

Route calls to: 

  • Main Trunk number :<By default number will be shown. You need cross verify with the number which you have purchased on telnyx portal>

  • Destination for calls during the office hours : <Based on your requirement>

  • Destination for calls outside the office hours : <Based on your requirement>

7. Select the "Options" tab

  • For "Require registration for:" select "Do not require". 

  • Remove the "GSM-FR" from Assigned Codecs 

  • Click "Apply"

8. Select the "Outbound Parameters"

  • For SIP Field “Contact: User Part” select “Custom Field” from the Variable dropdown. Leave the custom value blank.

  • Click "Apply". 

9. 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: 

  • I) General 

  • II) 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 : 

  • I) General 

  • II) Apply this rule to these calls 

  • III) Make outbound calls on


Rule Name : <You can enter any preferred name>

Apply this rule to these calls:

  • Calls to numbers starting with prefix : <leave empty>

  • Calls from extension(s) : <You need to give the extension numbers>

  • NOTE: ‘000’ is the extension I have used as an example. 

  • Calls to Numbers with a length of : <leave empty>

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.

This is also one of the many ways an outbound caller ID can be applied within 3CX. If you choose to apply an outbound caller ID on your Outbound Route, it will be applied to all calls that proceed through this route.

Note: If you choose not to add an outbound caller ID on your outbound route, you can instead apply it for each user or extension.

If a caller ID is not set through 3CX, it is likely that the calls will reach us without a caller ID. If this is the case, you may choose to apply a Caller ID Override from your SIP Connection’s outbound options in the Telnyx Portal. Otherwise, your calls will be rejected. Please review our caller ID number policy for accepted formats.

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

Review our getting started with guide to make sure your Telnyx Mission Control Portal account is setup correctly!

Checkout 3CX's help section for extra support!

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