Instructions for Configuring a 3CX V20 PBX Trunk

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

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.
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Click "Next".

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

On the "Timezone" tab, set your Time zone.

Click "Next".

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".

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

You can also configure this within the management console via Admin -> Advanced and selecting Allowed Country Codes.

Click "Next".

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

Click "Next".

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

Click on the admin cog on the bottom left-hand corner of the console and select Advanced.

Click on the IP Blacklist tab and ensure you allow the appropriate Telnyx SIP Signaling & Media IP Addresses. At the end of the article, you'll find a .json file, which you can use to import all Signaling & Media IPs.

Click on the Network tab

Click on the admin cog on the bottom left-hand corner of the console and select Users.

You'll want to create users so you can assign them DID's for inbound and outbound calls, as well as set their outbound caller ID and other important settings.

Click Add User - you will be brought to the General user settings where you can enter their first and last name for now, as seen below.

Click Save.

I've now created a dummy user called Telnyx HQ that I'll use in subsequent steps. Telnyx HQ has also been given extension 101.

NOTE: When user extensions are created, if an email is included, they will receive an email with their account details.

Click on the admin cog on the bottom left-hand corner of the console and select Voice & Chat.

Click on Add SIP Trunk → Add Trunk.

A new pop-up window will appear. Enter the following information:

Under VoIP Provider:

Main Trunk Number: Enter the Telnyx number you wish to use for your 3CX instance.

Since we're using credential-based authentication:

Type of Authentication: Select Register/Account Based.

Server Details:

Click the DID Numbers tab

Click the SMS tab

Enable Messaging: You can enable messaging on the DID by entering your Telnyx account's API Key.

Copy Webhook URL:

Provider URL:

Click Save.

At this point you can go back to Users and configure the DID to your Telnyx HQ user, as seen below:

Click back into Voice & Chat

Click on the Admin cog located in the bottom left corner of the console and select Outbound Rules.

Calls to numbers starting with prefix: <Leave this field empty>.

Calls from extension(s): <Enter the specific extension numbers>.
​Note: '100, 101' are examples of extension numbers.

Calls to Numbers with a length of: <Leave this field empty>.

Make outbound calls on:

This is where you will configure your routes. You can configure up to 5 routes for calls. The second and third routes will serve as backups.

Outbound Caller ID:

This is one of the ways to apply an outbound caller ID within 3CX. If you apply an outbound caller ID to your outbound route, it will be used for all calls that follow this route.
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Click Save.

Visit the Contacts section on the left side bar of the management console and create a new contact with the number in +E.164 format.

Use 3CX's built in WebRTC calling functionality and click the phone icon to call the test number. The WebRTC component will pop up on the right-hand side of the page to show you that the number is being dialed. Don't forget to allow the website access to your microphone and speaker!

3CX WebRTC client appears to change the + to 001 as the international exit code.

In this case, if your users want to dial internationally, you'll need to consider include a new outbound rule.

For testing purposes, I'll be using User extension 100.

I've downloaded the 3CX IOS app from the app store and opened it.

It's asked me to go back to the management console and click the QR Code icon, next to the phone icon, on the top right of your management console.

Then click scan QR code on your phone, allow the app access to your camera and point it at the QR code shown on the management console.

I want to make sure that calls to the main trunk number go to this user, so I went back to the Users section, clicked onto my original user, and assigned the main trunk number we configured at the beginning.

I've saved the settings so the changes apply and now I can ring my main trunk number and expect to receive the call on the 3CX app on my personal phone.

Two nice things to note here:

For testing purposes, I'll use the mobile app to compose an SMS that I will send from user extension 100 to user extension 101. That way we can see inbound and outbound messages in one go!

Visit the Chats section on the mobile app and click the pencil square icon.

A menu will open where you can choose:

I've chosen to Compose SMS.

Make sure that you have user extension 101 added as a contact, as then it can be looked up on the phone.

Compose your message and send it!

You'll also be able to these messages in the Messaging Report section of your account.

I logged in as user extension 101 in the management console, following earlier instructions I received via email to create a password and enable 2FA. Once I logged in I was able to see messages from user extension 100 and reply!