Award-winning SIP Trunks

Connect your PBX to the PSTN in minutes with Gradwell’s trusted SIP Trunks.​

Gradwell provides award winning sip trunks

What are SIP Trunks and how do they work?

Designed to replace traditional phone lines, SIP Trunks use broadband internet connections to connect your business phone system (PBX) to the traditional phone network (PSTN) without needing to replace your existing hardware.

With the PSTN network due to be switched off by 2025, now is an ideal time to experience the benefits of connecting your business phone system to the internet.

Gradwell guide to SIP trunks and their benefits

Benefits of SIP Trunks

Cost effective

Lower installation fees and monthly costs, including DID provisioning and call charges for both national and international numbers.

Improved service levels

Ensure that customers can reach you, wherever they (and you) are at a lower cost and via a quality connection.


Change location, expand into new markets and forward calls at a moment’s notice without any business disruption.

Easy management

Instantly provision additional resource as needed, on a permanent or temporary basis.

Flexible numbering

Regardless of physical location – even if this changes – present local, non-geographical or international numbers as needed.

Easy to scale

SIP Trunks are a cost-effective way to easily scale up or down depending on your business requirements.

Why Gradwell?

We are the UK’s SIP pioneers and we take pride in the resilience of our network. We have a team of over 20 developers who are constantly evolving and advancing our technologies. That’s why we’re trusted by hundreds of organisations for business-critical SIP services. See what else makes Gradwell stand out from the crowd…

Our own network

We operate and optimise our own network, security and systems directly from our HQ.

Cloud based

All of our SIP Trunks operate in the cloud.

Resilient and secure

We are ISO 27001 certified and our Network Operations Centre monitors our systems at all times.

Trusted by thousands

Thousands of UK businesses rely on us for secure and cost effective SIP Trunks every single day.

Recommended by the best

We are one of only a handful of suppliers to have 3CX preferred status, with a native 3CX integration and set-up.

Easy management

Manage your SIP channels through our easy-to-use centralised portal.

Specialist SIP services

We offer a wide range of bespoke SIP products to meet your specific requirements.
  • Direct Routing
  • Specialist 3CX SIP
  • High Volume

Use Microsoft Teams as your business phone system. Direct Routing is the process of connecting Microsoft Teams to the traditional phone network, or PSTN. It is an increasingly popular way to turn Teams from a powerful internal communications tool to a full-scale unified communications platform.

Learn more

We are a market-leading 3CX solutions provider – from onboarding and setup to support and maintenance, we help businesses feel secure when purchasing the 3CX system. Our end-to-end packages all include UK-based support, SIP trunks, connectivity and hardware. Deployed in a highly resilient cloud to guarantee service levels – not included in most suppliers’ standard offering.

Learn more

We have designed our own high-volume SIP Trunks specifically for customers needing high call-per-second and high channel capacity. Integrating directly with your existing PBX, our high-volume SIP Trunks allows you to take advantage of the cloud-based solutions, without replacing your existing equipment.

Learn more

Join thousands of businesses

We’ve helped organisations from across the UK take advantage of cloud-based communications tools. Can we help you?
Gradwell office meeting