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SIP Trunking

Bringing voice and data together


The way the business world uses voice services is changing.

Instead of using traditional methods to deliver voice and data separately, a single data pipe can now deliver both.

It’s more cost-effective, more efficient and future-proof. What’s not to love?


SIP (Session Initiation Protocol) is a communications standard that’s becoming universally adopted in businesses across the globe.

SIP Trunking uses this standard to allow VoIP (Voice over IP) calls to be made to and from traditional phone lines, using a data network.

Put simply, SIP Trunking uses our IPVPN service and provides a connection from the network to link your IP PBX to our soft switch. This connection allows voice traffic to be carried as VoIP across the network and on to the PSTN (Public Switched Telephony Network).


The evolutionary successor to ISDN30, SIP Trunking offers the following benefits:

  • Cost efficient – when replacing an existing ISDN30 network, cost efficiencies can be made as the rental charges on SIP Trunking are typically lower than on ISDN30.
  • Streamlined channels – SIP trunks can be shared between multiple sites and you can generally reduce the number of channels you need compared with ISDN30, which requires installation at each site.
  • Future-proof – SIP is now the standard on which IP PBXs are built. By deploying our SIP Trunking service, you are future-proofing your business for Unified Communications and an easy integration with leading vendor solutions.
  • Advanced call-handling features – DDI (Direct Dialling Inwards), CLI (Call Line Identity), CLIP (Caller Line Identity Presentation), CLIR (Caller Line Identity Restriction) and Presentation Numbers are all supported.
  • Greater efficiencies – any spare connectivity capacity can be used for internet access and WAN connectivity.

Why Virgin

Our industry leading experts have years of experience in delivering transformative tech to all sizes of companies from small businesses to large corporations.

Here’s what you can expect from us:

  • Reliable, business-grade spec – our circuits are backed up with the UK’s largest nationwide fibre-optic network and one of the biggest TDM voice networks in the country.
  • Geographic resilience – enhanced options are available at additional cost, including a secondary transport route between our network and yours. 
  • IPVPN included in the cost – our SIP Trunking service lets you get the most of your network investments by delivering business voice over our Managed IPVPN service.
  • Connection options – we can connect to a range of IP PBXs and other equipment. 
  • Migration plans to suit you – we’ll manage your migration to avoid any interrupted service to your business and work with you to replace your legacy telephony equipment and phone lines with IP telephony at your speed for the smoothest transition.
  • Efficient installation – when combining voice and data, fewer engineer visits are required, meaning reduced installation costs and less disruption on site.
  • Flexibility when needs change – our SIP Trunking solution is more flexible when moving or changing your services because there’s less reason to alter, change or modify phone sockets, re-route cabling or pull up floorboards. We believe in smooth operations.