SIP Trunks

Future-proof your business communications with SIP trunking from LCUK. SIP (Session Initiation Protocol) trunks provide a modern, flexible alternative to traditional ISDN phone lines — delivering high-quality voice calls over your internet connection.

What Are SIP Trunks?

SIP trunks connect your on-premise phone system (PBX) to the public telephone network via the internet, instead of using legacy phone lines. This technology enables voice, video, and messaging over IP, offering a more cost-effective and scalable solution for businesses of all sizes.

Why Move to SIP?

With the UK’s ISDN and PSTN networks being phased out by 2025, SIP trunking is the recommended upgrade path for businesses still using legacy telephone lines. It offers improved flexibility, lower call costs, and greater control.

  • Cost Savings: Lower line rental and call charges
  • Scalability: Add or remove channels as your business grows
  • Business Continuity: Easily reroute calls during outages or office moves
  • Number Flexibility: Keep existing numbers or use non-geographic numbers
  • Better Call Quality: HD voice over secure IP connections

Perfect for On-Site and Hybrid Systems

If you’re not ready to move fully to hosted VoIP, SIP trunks offer the best of both worlds. You can retain your existing PBX while upgrading to a modern, IP-based voice service.

Compatible with Yeastar and Legacy Systems

Our SIP trunks are fully compatible with modern systems such as Yeastar PBX platforms, as well as older hardware from Panasonic and Samsung. We’ll ensure a smooth transition with minimal disruption to your operations.

Reliable, Secure & UK-Based Support

LCUK provides SIP trunks backed by high-availability networks and strong security measures, including fraud protection and call encryption. All services are fully supported by our UK-based technical team.

Included Features:

  • Free UK geographic number ranges
  • Optional call recording
  • CLI presentation
  • Disaster recovery options
  • Compatible with Microsoft Teams (optional integration)

Switch Today with Expert Help

Ready to move away from ISDN or need a more reliable SIP provider? LCUK will handle the number porting, configuration, and setup to get you up and running quickly.

Contact us to learn more about SIP trunks, or request a free quote today.