3CX SIP Trunk Providers - UK

These SIP Trunk providers in the UK have been tested and certified by 3CX. We strongly recommend using a preferred or supported SIP Trunk service provider. The 3CX team makes sure that all templates from listed SIP Trunk Providers are updated and tested with every release ensuring no issues arise for our users.

Registration-based trunks with no IP fixation remain the preferred option in a hosted environment. This is because in certain cases the Public IP of your Hosted by 3CX can change unexpectedly. Although this is not a regular occurrence, if this happens, you will temporarily lose the ability to make and receive calls via your IP-based trunks.

Read our guide on how to configure a SIP Trunk / VoIP Provider. This covers the generic steps required to configure a trunk with 3CX. Some providers may need special configuration requirements. Before choosing a SIP Trunk provider in your region, carefully check our listing for these special requirements and be sure to follow any extra configuration guides added.

Preferred Providers

Preferred Providers are compatible with all 3CX installation modes. They are thoroughly tested with each build of 3CX and require no manual configuration. You can simply plug and play your PBX with a SIP Trunk of your choice.

fuse2 communications logo

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 the national format (e.g. 07975777666).

gradwell uk sip trunk

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).

Supported Providers

Supported Providers are tested against 3CX Hosted and on-premise installations. Compatible with all 3CX installation modes.

Brightstar Logo

Capabilities 

SMS Support No
Anonymous Calling Yes
Clip No Screening Support Yes
Fax Support No
SIP TLS Support No
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.

Telxi Sip Trunk logo

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).

T4Com Logo

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.

Vodafone Logo

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 Yes

Important Configuration Notes

Enter the main trunk number as E164.
Be sure to follow the configuration guide.

VoiceHost Logo

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.

Supported (Dedicated Servers Only)

Supported Providers (Dedicated Servers only) are tested against 3CX Hosted and on-premise installations. Not compatible with 3CX FREE/SMB. Configuration may require a few extra steps.

BT Logo

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.

BT Wholesale Logo

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.

Gamma Logo

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.

spitfire logo

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).

Voiceflex Logo

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.

Yellowgrid Logo

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.

Zen Logo

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).