SIP Trunking

SIP Trunking

Our SIP trunking solution lets you reduce your on-going call costs by replacing expensive analogue and digital lines with a data connection for your telephone calls over IP. SIP Trunking is also available via broadband or a Leased Line connection.

SIP trunking is ideal if you:

  • Currently use traditional ISDN services at one or more location and are looking to rationalise the number of lines you require
  • Are moving offices and want to keep existing numbers but avoid call forwarding charges
  • Need a resilient phone service to cope with an emergency at one or more sites
  • Want to use local numbers from any region of the UK, giving your business a local presence without opening local offices
  • Require telephony services up and running quickly



Getting the basics right for Unified Communications

The Benefits of SIP Trunking

Save Money
Intercity’s SIP Trunking service saves you money because IP connectivity costs are lower than ISDN and PSTN lines.

Add to that the free ‘branch to branch’ calls nationally and internationally, lower line rental, low set up costs and the elimination of expensive call-forwarding services you can quickly see how the cost of calling drops dramatically.

Continuity and Disaster Recovery
To ensure your business stays up and running in the event of an emergency we provide you with a SIP account on our secure network for your PBX and its associated phone numbers.

In the event of one of your sites being inaccessible, you can use your account to redirect calls almost instantaneously to another PBX at one of your other locations. Alternatively service can be restored by moving the PBX at the disabled site to another location with an IP connection.

SIP Trunking is an extremely flexible solution. You can use local numbers irrespective of the location you’re working from. What’s more you’ll also be able to move your numbers to Intercity quickly and easily with little or no disruption to your service.

Supports multiple locations
SIP Trunking lets you rationalise the number of ISDN lines and onsite PBXs you need to maintain, whilst giving you full control of telephone associated with each site.

Easily scale up your telephony
SIP is easy to scale and can have additional channels or DDI’s up and running within 24 hours. Using a simple communication gateway we can make SIP work with your existing telephone system and so avoiding the need for an equipment upgrade.

Voice and data convergence
By choosing to route both call and data traffic over one of our Ethernet Leased Lines we can help you reduce costs and line management headaches even further.


This depends on your current Internet connection and how many simultaneous calls you want to make. The size of a SIP voice call is just over 1ookbps, so for example, a 10/100Mbps data circuit used only for voice telephony supports about 80 concurrent calls.

Most modern telephone systems support SIP although some settings may need to be changed. If you have an older phone system we can use a special appliance called a gateway to enable your system to start using SIP. Our product specialists will be able to give you advice on compatibility and settings.

Talk to us for more information regarding the benefits of SIP Trunking

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