3CX SIP Trunk Providers - UK
The SIP Trunk Providers listed for the UK have demonstrated compatibility with the 3CX Phone System. They are categorized as either 3CX Tested, where testing is completed directly by 3CX, or VoIP Provider Tested, where the provider completes the required testing and submits the results to 3CX for review. We recommend choosing a listed provider and checking its interoperability category, capabilities and configuration notes before setup.
For hosted installations, registration-based trunks that do not require a fixed IP are preferred. In certain cases, the public IP address of a Hosted by 3CX system may change. Although uncommon, this can temporarily affect incoming and outgoing calls when using an IP-based trunk.
Read our guide on how to configure a SIP Trunk / VoIP Provider. It explains the general steps for configuring a trunk with 3CX. Some providers have additional requirements, so check the provider’s listing and follow any configuration notes or guides provided.
3CX Tested
These providers have been tested directly by 3CX and meet the applicable technical, support and commercial requirements. Their pre-configured templates are available in 3CX for quick and easy setup.
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | No |
| Fax Support | Yes - T38 Bypass |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No/Yes |
Important Configuration Notes
Enter the main trunk number in international format (e.g. 447975777666).
Be sure to follow the configuration guide.
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | No |
| Fax Support | Yes - T38 Bypass |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | Yes |
Important Configuration Notes
Enter the main trunk number in the national format (e.g. 07975777666).
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | No |
| Fax Support | No |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No/Yes |
Important Configuration Notes
Enter the main trunk number in international format (e.g. 447975777666).
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | Yes |
| Fax Support | Yes - T38 Upscale |
| SIP TLS Support | Yes |
| IPV6 Ready | No |
| Online Sign-Up & Portal | Yes |
Important Configuration Notes
Enter the main trunk number as E164.
Be sure to follow the configuration guide.
Capabilities
| SMS Support | Yes |
| Anonymous Calling | Yes |
| Clip No Screening Support | No |
| Fax Support | No |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | Yes |
Important Configuration Notes
Enter the main trunk number as E164.
Be sure to follow the configuration guide.
VoIP Provider Tested
These providers have completed the required 3CX interoperability testing and submitted their results for review. Once approved, their pre-configured templates are made available in 3CX. This category does not mean that 3CX has directly tested the provider’s overall service.
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | Yes |
| Fax Support | No |
| SIP TLS Support | Yes |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No |
Important Configuration Notes
Enter the main trunk number as E164.
Be sure to follow the configuration guide.
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | Yes |
| Fax Support | Yes - T38 Upscale |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No |
Important Configuration Notes
Enter the main trunk number in national format (e.g. 07975777666).
Be sure to follow the configuration guide.
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | Yes |
| Fax Support | Yes - T38 Bypass |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | Yes |
Important Configuration Notes
Enter the main trunk number as E164.
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | Yes - Separate Service |
| Fax Support | Yes - T38 Bypass |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No |
Important Configuration Notes
Enter the main trunk number in national format (e.g. 07975777666).
Gamma Trunks support Clip No Screening as long they are CLI Flex trunks, which means you can present the originator caller ID for forwarded calls.
For calls directly from the PBX to Gamma, the outbound caller ID presented must belong to your trunk. This is to ensure that emergency calls always present the correct caller ID to emergency services.
Capabilities
| SMS Support | No |
| Anonymous Calling | No |
| Clip No Screening Support | Yes |
| Fax Support | Yes - Audio |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No |
Important Configuration Notes
Enter the main trunk number in the E164 format (e.g. 441234567890).
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | No |
| Fax Support | No |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | Yes |
Important Configuration Notes
Enter the main trunk number in the international format (e.g. 447975777666).
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | Yes |
| Fax Support | Yes - T38 Bypass |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No |
Important Configuration Notes
Enter the main trunk number as E.164.
For forwarded calls, both the outbound caller ID of the PBX as well as the originator's caller ID will be sent in different SIP headers so it depends which SIP header the end destination is using to read caller IDs.
Capabilities
| SMS Support | No |
| Anonymous Calling | No |
| Clip No Screening Support | No |
| Fax Support | Yes - T38 Bypass |
| SIP TLS Support | Yes |
| IPV6 Ready | No |
| Online Sign-Up & Portal | Yes |
Important Configuration Notes
Enter the main trunk number in the E164 format (e.g. 441234567890).
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | No |
| Fax Support | Yes - T38 Bypass |
| SIP TLS Support | Yes |
| IPV6 Ready | No |
| Online Sign-Up & Portal | Yes |
Important Configuration Notes
Enter the main trunk number as E164.
You can only present numbers associated with your account as Outbound Caller ID.
Be sure to follow the configuration guide.
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | Yes |
| Fax Support | Yes - T38 Bypass |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No/Yes |
Important Configuration Notes
Enter the main trunk number as E164.
Be sure to follow the configuration guide.
Capabilities
| SMS Support | No |
| Anonymous Calling | Yes |
| Clip No Screening Support | No |
| Fax Support | Yes - T38 Bypass |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No |
Important Configuration Notes
Enter the main trunk number in national format (e.g. 07975777666).
Yellowgrid SIP Trunks Clip No Screening as long they are CLI Flex trunks, which means you can present the originator caller ID for forwarded calls.
For calls directly from the PBX to Yellowgrid, the outbound caller ID presented must belong to your trunk. This is to ensure that emergency calls always present the correct caller ID to emergency services.
Capabilities
| SMS Support | Yes |
| Anonymous Calling | Yes |
| Clip No Screening Support | No |
| Fax Support | No |
| SIP TLS Support | Yes |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No |
Important Configuration Notes
Yellowgrid Advanced SIP
Enter the main trunk number in national format (e.g. 07975777666).
Capabilities
| SMS Support | No |
| Anonymous Calling | No |
| Clip No Screening Support | No |
| Fax Support | Yes - Audio |
| SIP TLS Support | No |
| IPV6 Ready | No |
| Online Sign-Up & Portal | No |
Important Configuration Notes
Enter the main trunk number in national format (e.g. 07975777666).
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