3CX: Configuring a 3CX V18 v4 PBX - Credentials Trunk

Setup guide for 3CX V18 PBX Credentials Trunk integration with Telnyx for VoIP calls.

Written by Customer Success
Updated over a week ago

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!

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 V18 PBX Credentials Trunk

In this guide you will:

Video Walkthrough

Setting up your Telnyx SIP portal account so you can make and receive calls:



3CX will detect your pubic IP address and you can specify if this is a static or dynamic IP.

You can configure your 3CX with an FQDN; 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.

1. Perform the basic setup

In this step, you'll do a basic configuration before creating your Telnyx SIP trunk.

1.1 Login Process

Log into 3CX with the username and password provided to you during the installation process.

1.2 Extension Length

On the Extension Length tab, specify your extension length by choosing how many digits your extension should have (default is 3). Note that this CANNOT be changed later.

Click Next.

1.3 Admin Email

On the Admin Email tab and enter an email you want to use to receive system notifications and other important information.

Click Next.

1.4 Timezone

On the Timezone tab, set your timezone.

Click Next.

1.5 Operator

On the Operator tab, you can specify a default operator extension. This will be the default destination for all inbound calls, as well as a voicemail extension.

Click Next.

1.6 Allowed Countries

On the Allowed Countries tab, you can select all regions permitted for outgoing call.

Click Next.

1.7 Prompt

On the Prompt set tab, you can select the language spoken by your automated prompts.

Click Next.

1.8 Registration

On the Registration tab, enter your personal detail to register your setup.

2. Configure your PBX

In this step, you'll configure everything needed to start making and receiving calls with 3CX through Telnyx, including network settings, SIP trunks, inbound/outbound routes etc.

2.1. Confirm your network settings

  1. Click on the Ports tab and ensure your SIP port is set to 5060.

  2. Click on the Public IP tab and ensure that your Public IP is correct and that you have selected the proper Network card Interface.

  3. Click on the Settings tab and click on Network Settings and then on the Public IP tab. Find the External IP Configuration section and ensure that the connection IP on the portal matches the Static Public IP.

2.2. Create a Telnyx SIP Trunk

Create a SIP Trunk

  1. Click on SIP Trunks in the left-hand navigation menu.

  2. Click + Add SIP Trunk near the top of the screen.

  3. A new pop up will open. Enter/select the following:

    1. Select Country: Worldwide

    2. Select Provider in your Country: Telnyx LLC

    3. Main Trunk No: <Enter the number which you have purchased on your Telnyx Mission Control Portal>

  4. Click OK. This will open the trunk configuration window.

Set the authentication

  1. Click on the the General tab and find Trunk Details:

    1. Enter name of Trunk: Telnyx LLC

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

    3. Outbound Proxy: sip.telnyx.com

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

  2. Find the Authentication section:

    1. Type of Authentication: Register/Account based

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

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

  3. Find the Route calls to section.

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

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

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

  4. Click on the Options tab.

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

    2. Remove the "GSM-FR" from Assigned Codecs

    3. Click "Apply"

  5. Select the "Outbound Parameters"

    1. SIP Field

      1. Contact: User Part: Select Custom Field from the Variable dropdown. Leave the custom value blank.

      2. From: Display Name" and From: User part select OriginatorCallerID from the Variable dropdown.

  6. Click Apply.

9. Click OK to make the IP trunk live.

2.3. Configure inbound rule

  1. Click on "Inbound Rules" from the navigation menu on the left.

  2. Click on "+Add DID Rule" near the top of the screen.

  3. Find the General section and ensure the following:

    1. Name: IB_Telnyx (or any name that can identify your inbound rule)

  4. Find the Route calls to section and ensure that:

    1. Destination for calls during office hours: Extension and ensure that your desired extension is selected (is usually 000).

2.3. Configure outbound rule

  1. Click on Outbound Rules from the navigation menu on the left.

  2. Click on +Add near the top of the screen.

  3. Find the General section and ensure the following:

    1. Name: OB_Telnyx (or any name that can identify your outbound rule)

  4. Find the Apply this rule to these calls section and fill in the following:

    1. Calls to numbers starting with prefix : <leave empty>

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

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

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

  5. Find the Make outbound calls on section. This is where you will configure your routes. You can 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.

Depending on your use case, you may have specific dialling format rules and 3CX provides a great overview here.

After completing this configuration, click "OK".

An important example of an outbound rule

The outbound rule feature in 3cx is a powerful tool for configuring your 3CX phone system that extra mile allowing you to create much more complex rules – allowing you to not only select backup routes which come into effect when other routes fail, but also to select a different set of routes, depending on the type of number being dialed. Below you will find an example outbound rule for handling 911 Emergency Calls:

For additional outbound rule examples which you may find useful please see the following support article from 3CX.

That's it, you've now completed the configuration of 3CX V18 PBX Credential 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!

Additionally, you can check out:

Can't find what you're looking for? Click the chat bubble at your lower right hand corner and start a chat!

*Note that you must be logged into your Telnyx Mission Control Portal in order to interact with the chat bubble.

Did this answer your question?