What are SIP Trunks?

Session Initiation Protocol (SIP) trunking is a service offered by a communications service provider that uses the protocol to provision voice over IP (VoIP) connectivity between an on-premises phone system and the public switched telephone network (PSTN). SIP is used for call establishment, management and tear-down. SIP trunking is typically sold as a replacement for digital Primary Rate Interfaces (PRI's), which are based on time-division multiplexing (TDM) and offers considerable savings on both rental and calls.


  • Reduce spend
  • Ability to scale on demand
  • Simplified administration
  • Greater reliability
  • Geographic independence
  • Business continuity planning
  • Proven technology

We provide SIP trunks and inclusive call packages as priced below:

Description Charge Type &  Frequency Cost
SIP Trunk (Each SIP Trunk includes 5000 minutes to 01,02,03 and UK Mobiles) Monthly Rental £7.95 + VAT
Set up per end point/customer One Off Connection £75.00 + VAT
Virtual Number Monthly Rental £2.25 + forwarding costs
DDI per number (geographic or non-geographic number) Monthly Rental £0.23 + VAT (each)
Private SIP (using private Interconnect) includes bundle as above Monthly Rental £9.83 + VAT
Private SIP Set up per end point/customer One Off Connection £140.00 + VAT

SIP Fail-over Options

Requires two end points/sites on our SIP platform

  • Round Robin - Incoming calls are sent alternately to two end points/sites
  • Simultaneous - Incoming calls are sent to both end points/sites at the same time and whichever accepts the call first takes it
  • Sequential - End point/site 1 is sent all calls by default, if it does not respond, calls will be sent to end point/site 2

Requires one end points/site on our SIP platform

  • Off-Net Divert - If the end point/site is unavailable, incoming calls will divert to an off-net number. Call charges will apply for diverted calls.