Configuring a Sinch Elastic SIP Trunk
About Sinch
Sinch is a global cloud communications provider based in Sweden, offering messaging, voice, and video services to businesses. It helps companies connect with customers at scale through SMS, voice calls, and other APIs. Sinch serves over 150,000 businesses and reaches billions of mobile users worldwide.
Step 1: Create an Account with Sinch
If you do not already have an account with Sinch head over to Sinch’s website and create an account. You need to have access to the Sinch dashboard to be able to create a SIP trunk and add it to 3CX.
Step 2: Buy Phone Numbers
After you have created an account you will need to buy phone numbers. You can buy numbers by navigating to “Numbers” → “Get Virtual Numbers”. Select the numbers you want and order them.
Step 3: Create a SIP Trunk
- Navigate to “Elastic SIP Trunking” → “Trunks” and create a new SIP trunk.
- Give your trunk a name and create a Domain name. Save that domain name for later as you will need it to create the trunk in 3CX.
- From the next screen click on “Add an Endpoint” and proceed to create a new one. Select the “Registered” option and give it a name.
- Click on “Manage Credentials” to create a new username and password for the trunk. Save them as you will need them later on.
- In the trunk settings Create a new ACL with your 3CX PBX public IP and assign it to the trunk.
- Also assign your credentials list which was previously created.
- Lastly click on “Assign Numbers” and select the numbers you want to associate with your trunk.
Step 4: Setting Up your Trunk in 3CX
Once you have your numbers, registrar, username and password gathered from Sinch’s Dashboard you are now ready to add your Sinch trunk in 3CX.
- Navigate to “Voice & Chat” and click on the “Add Trunking” option. Select the “Sinch Elastic SIP Trunk” from the list and click “OK”.
- Give your trunk a name and scroll down to the “Account Details” section. There add your main trunk number, this can be any number from the DIDs you bought.
- Add your authentication ID and authentication password which you created in the Sinch portal.
- And lastly add the domain name you created under the “Registrar/Server” field.
- Save the trunk and you are ready to make and receive calls
See More
- See more 3CX supported SIP trunk providers
Last Updated
This document was last updated on 29 May 2025