Squanto Tech are proud to be partnered with Gamma who provide the SIP services described on this page. You can order your Gamma SIP service through Squanto Tech, and we will take care of ensuring you get the right solution for your business, answer any questions you may have, and we're here to help you integrate it. To find out more how Gamma SIP solutions can differentiate your business proposition and enhance your communications, contact us

You can also download a pdf version of this page here

Reliable Voice services with flexibility and continuity

SIP Trunking

SIP trunking is rapidly replacing ISDN services for inbound and outbound voice calls and Gamma is the UK’s leading SIP trunks provider. Our SIP trunks connect your site’s PBX directly into the Gamma network via an internet connection to carry and terminate your calls across the public telephone network.

Gamma SIP Trunks provide a highly-flexible alternative to ISDN and are compatible with all the leading IP PBX brands in the UK market, giving you peace of mind that your PBX hardware works with the network service.
Compared to ISDN, Gamma SIP Trunks are cheaper on a per-channel basis and more flexible in terms of what telephone numbers you can have and the locations in which you can have them. In addition, they are quicker to install and offer a robust business continuity service that ensures your business never loses any calls.
Any business with a PBX can switch to our SIP trunking service and immediately benefit from a more flexible, less expensive and more resilient phone service.

How it works


Gamma SIP Trunks connect your PBX to Gamma’s network, enabling full PSTN breakout on the public telephone network. Connection from your site (or sites) to our network is via an internet connection (broadband or ethernet) or a private access circuit for more secure services. The service is delivered end-to-end with a 99.99% availability, voice channel guarantees and voice Quality of Service.

Smarter Working

Save money, work flexibly and collaborate with reassurance

Save money on call costs and line rental

Sip Trunking delivers less costly, more reliable connectivity than ISDN over an internet connection. It can save up to 50% on line rentals and 25% or more on call costs

Free Internal calls and great features

Perfect for medium or large organisations with multiple sites, SIP Trunking will you save on your line rental and call costs and you’ll get free internal calls within your organisation together with a whole host of great features

Scale up and down when you need to

SIP trunks are ideal if you are moving, upsizing or downsizing and want to keep your existing numbers. Scale up lines during busy periods and back down again afterwards. You can add lines, take them away, split calls at any time. You are always in control.

Business Continuity built-in

SIP trunks can handle emergencies easily. They are inherently disaster recovery / business continuity ready, letting you reroute calls to an alternative location quickly and easily.

Compatible with leading business networks and applications

Gamma SIP trunks are integration tested and approved to interoperate with Microsoft Skype® for Business, allowing you to directly connect to the platform to make external calls.

Skype® for Business delivers a simple and fast communications platform for businesses that lets you instantly see any colleague’s presence status and communicate with them using instant messaging, conferencing and voice, helping businesses reduce operating costs and save time.

In today’s unified communications environment  the transition from legacy to VoIP is happening faster than ever before. This latest accreditation adds to the expanding list of platforms already qualified for use with Gamma SIP Trunks. Enterprise voice is now an integral part of the Skype® for Business proposition and, by gaining this accreditation, users now have access to one of the UK’s leading SIP providers.

We’re also a Janet-connected partner with an interconnect to provide voice services through Gamma SIP Trunks to the Janet community. Janet is the network dedicated to the needs of research and education in the UK, connecting institutions to each other, as well as to the rest of the world

Gamma Sip Trunks and your PBX

Conformance tested with all UK IP PBX manufacturers

Here are just some of the IP PBX and SIP Gateway vendors Gamma work with:

PBX - on your premises or in the cloud?

Using Gamma SIP Trunks, your PBX can be located either at your company site or housed within a managed colocation centre provided by Gamma where you don’t need to be concerned about space, power or support engineers to look after your PBX. Either scenario is possible and for added resilience and flexibility you may wish to use a combination of both support models.

A typical dedicated hybrid hosted PBX implementation

Business solutions

Helping your business thrive, with built-in protection 

Number Flexibility

Gamma SIP Trunks support business relocations by enabling a geographic number to be retained without call forwarding costs. This ensures business continuity and reduces the costs of having to change company stationery, listings and advertisements.
As a leading UK communications provider we can also supply out-of-area geographic number ranges to make your organisation appear local, even without a physical presence

Business-grade voice and internet convergence

With our SIP trunks delivered over Gamma Broadband or Gamma Ethernet, you can have a high-quality voice and data service from just one connection, making for significant cost savings.

Line and PBX estate rationalisation

For businesses with several locations, our SIP trunking service provides ISDN line rationalisation; the ideal way to reduce the number of PBXs requiring maintenance

Business Continuity

Businesses of all sizes need a business continuity plan for telephony. Combine our SIP trunks with our Inbound service and your callers will always get through. Set automated call plans or simply divert published numbers to backup locations or mobile devices – instantly and from anywhere.

Affordable resilience

If you’ve ever had to deal with a service outage you’ll know that speed of response is key. Our active/standby and load sharing designs are engineered to cope with any situation to maintain telephony uptime. Whether you need to keep your businesses running in an emergency without the high cost of call forwarding or simply need to balance call loadings between sites during peaks, Gamma SIP Trunks will provide a business grade solution.

Free UK calls

Our SIP trunking service provides free call termination to UK fixed destinations, including 01, 02 and 03 number ranges. It also provides free calls between connected sites, including international locations.

Protection from phone hacking and misuse

Hacking and abuse of business telephony is becoming as big as credit card fraud. With this type of abuse, the cost of the calls falls to your business. But with our CallGuard service all of your existing business numbers are protected from such activity.

·          Your calls protected from unusual usage

·          Avoid unwanted, expensive bills

·          Tailor your protection - opt numbers in and out

·          Peace of mind

Flexible Gamma SIP Trunks for real business issues

With Gamma SIP Trunks you get a service that is more robust and cost-effective than ISDN.  Because SIP trunking is an internet-based telephony service, you also get number flexibility, which gives you a whole host of other added benefits that can solve real business issues.  Here are just some of the other ways that Gamma SIP Trunks can enhance your business

Business Continuity

Use Gamma SIP Trunks to protect your office environment in case of fire, flood or other natural disaster. For example, if your London branch has to close in an emergency and you need calls routed to Manchester immediately, Gamma SIP Trunks can do this and at no extra charge to you. Set up at your new location is quick and easy and there are no call-forwarding costs for each inbound call.

Disaster Recovery and service resilience

By having two PBXs, each at a separate site and each with its own connection, you will always have service availability. Should one site go down, your inbound and outbound calls can automatically be rerouted to the second site in an instant and without any prohibitive call-forwarding charges. With this set-up, you can also share the load on inbound calls to two or more sites. You may choose to have your second PBX off-site at a colocation centre, thereby avoiding the full cost of a second PBX. Alternatively you may wish to use your existing ISDN line as a back up. For absolute resilience Gamma SIP Trunks can be combined with our Inbound service. In the unlikely event that all of your SIP trunking services are unavailable, you can still instantly reroute your inbound calls to any destination by redirecting them to your number of choice.

Multi-site rationalisation

Does your business have multiple sites? Do you have an ISDN connection into an individual PBX at each site? Using SIP trunks you can reduce the number of ISDN connections that your business requires and also reduce the maintenance costs on all of your various PBXs. At remote sites you are left with just the cost of an internet connection and the handsets that you need. You can then pull all the telephony traffic back into your cloud-based PBX. You can also benefit from increased resilience by building an automatic failover system into your communications strategy for lines and calls should your main site go down. With SIP trunks you can instantly centralise and distribute the calls somewhere else, to another site or to homeworkers, for example.


Gamma SIP Trunks are valuable for businesses with seasonal voice capacity requirements where more lines need to be quickly and easily implemented with no long-term commitments, for example when running sales campaigns or during major sports or entertainment events. Unlike ISDN, SIP is a highly cost-effective system that

Business relocation

Number flexibility with Gamma SIP Trunks means that you can keep your existing number, even when moving out of the area, saving you costs on printed company literature and stationery whilst maintaining the perception that you still have a presence in the area you’ve moved from.  We can easily transfer your old or existing numbers to Gamma SIP Trunks so that you can avoid expensive  Remote Call Forwarding (RCF) or call diversion charges.

The Payment Card Industry Data Security Standard (PCI DSS) is the proprietary information security standard defined by the major card companies to help combat fraud and protect consumer card data. Its members include Visa, MasterCard, American Express, Discover and JCB. PCI DSS applies to all organisations that store, process or transmit cardholder information, from any of these members’ cards. The type of annual assessment required varies according to “level”, which
is defined according to the volume of payment transactions
that are handled.

With 327 controls to consider in total, it is vital to ensure you have them all ticked. The effects of being non-compliant can be disastrous for a business due to the very real financial risk of opportunistic agent fraud and the associated reputational risks. Some of these include:


  • Compromising your customers’ payment data

  • Loss of customers, damage to your brand and reputation

  • Expensive lawsuits and insurance claims

  • Substantial payment card user and Government fines


We’ve partnered with Semafone to offer a flexible and cost-effective telephony solution to ensure your organisation remains compliant when taking Cardholder Not Present (CNP) payments over the phone. Combining our market leading Gamma SIP Trunks with Semafone’s award winning solution protects your business from risk.


It’s quick to install, helps to improve agent productivity by reducing average handling times and supports connections ranging from two channels to an unlimited number.

PCI DSS Compliance

Taking the worry out of SIP migration

How good is call quality?

From the moment we connect your SIP trunking service, you will enjoy all the reliability, resilience and quality that comes from working with the UK’s leading SIP trunk provider. We proactively monitor and manage quality of service across our entire network – it’s the underlying network quality that makes a real difference to SIP trunking. As a consequence we are able to support both G.729 and G.711 codecs.

Is SIP resilient?

SIP trunking is now a mature service enjoyed by thousands of UK organisations and this alone is testimony to the reliability of SIP. For added reassurance while you switch to us, SIP trunking can even be used with existing ISDN connections to ensure the transition goes smoothly.


Owning our own national network means we can identify and fix issues faster, through our advanced monitoring and diagnostic tools.

What if we want to move offices?

Number flexibility with SIP trunking means that you can keep your existing number, even when moving out of the area whilst maintaining the perception that you still have a presence in the area you’ve moved from. We can easily transfer your old or existing numbers too so that you can avoid expensive remote call forwarding or call diversion charges.

With CLI flexibility you can also decide which number you want to display on a call by call basis – great for contact centres.

What if we lose internet or power?

Should the unthinkable happen, you can use SIP trunking to minimise disruption to your business. For example, if your London branch has to close in an emergency, and you need the calls routed to Manchester immediately, Gamma SIP Trunks can do this and at no extra charge to you.

Can we add or remove some lines?

SIP trunks are valuable for businesses with seasonal voice capacity requirements where more lines can be quickly and easily implemented with no long term commitments, for example when running sales campaigns.


Conversely, if your business has multiple sites with ISDN connections into each, using Gamma SIP Trunks you can reduce the number of ISDN connections that your business requires and also reduce the maintenance costs on all of your various PBXs. At the remote sites you are left with just the cost of an internet connection and the handsets that you need and you can then pull all the telephony traffic back into your centralised PBX.

SIP Trunk Call Manager for cloud-based call control

SIP Trunk Call Manager offers a powerful business continuity solution, giving you the ability to consolidate all your numbers onto a single platform and never miss a call. Cloud-based call control allows you to automatically direct calls to a destination you define such as a colleague, mobile, hunt group or call queue. Combined with all the features and benefits of Gamma SIP Trunks, including our call bundles and the only fraud management tool that protects you and your customers by enabling them to set spend limits, SIP Trunk Call Manager is a hugely powerful business tool.

Powerful business features

SIP Trunk Call Manager comes with a portfolio of business features which, when combined with the ability for the user to fully control the service via a mobile app, provides a powerful business solution.

Delivering added value

SIP Trunk Call Manager takes SIP beyond a connectivity service with additional business features, applications and user-led control to bring additional value to the business.

Enhanced SIP service -
Gives you full and direct control of your inbound numbers

Tailored business continuity -
Never miss a call

Accelerate ISDN conversion -

Why buy a simple SIP trunk when you can have so much more

No number translation -
01, 02, 03 and 08 termination on subscribed Gamma SIP Trunks

Easy management -
Mobile app and web portal

  • Twitter Social Icon
  • LinkedIn Social Icon

©2019 by Squanto Tech.

Follow us on