4Sight SIP Trunks
The cost-effective and flexible alternative to ISDN

As a Gamma Gold Partner, 4Sight provides SIP Services that offers a highly-flexible alternative to ISDN. With our SIP Trunks you get a service that is more robust and cost-effective than ISDN. Our service can support connections ranging from two channels for businesses with small PBXs, with no limit on the number of channels that can be supported for large enterprises and contact centres.
Compared to ISDN, 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.
Benefits Snapshot
The benefits of moving to SIP trunking can transform business communications and the process of switching is simple and safe, even for the most risk averse of businesses.
Get in touch to see how we can help your business transition from ISDN to SIP
Why Choose 4Sight?
Our SIP trunks connect your site directly into the Gamma network via an IP connection to carry and terminate your inbound and outbound voice calls across the public telephone network. They 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.
Switching to SIP Trunks with us provides many benefits including:
Free Local, National and UK Mobile Calls*
Fixed charge of £ PCM per Channel
Free analysis of your line and billing information
Free Project Migration Management and Setup
Free Setup
Competitive International Rates
SIP Trunk Call Manager - putting you in control with powerful business continuity and future-rich centralised call control, together with all the benefits from your existing SIP Trunks.
SIP Trunk Call Manager provides you with all the benefits of 4Sight Gamma SIP Trunks together with feature-rich, centralised call control. This includes our market-leading call bundles and the only fraud management tool that financially indemnifies you against loss.
If you are looking for a solution that offers powerful business continuity and the ability to fully manage your entire number estate directly via your SIP trunks, SIP Trunk Call Manager is the ideal solution.

*This is a channel inclusive deal that offers inclusive UK calls to Local, National, Uk Mobile and 03xx Numbers. There are terms that apply to this offer that require a minimum term of 3 years commitment. There are some restrictions when migrating existing Gamma clients to 4Sight Gamma services which we will advise if applicable. There is also a fair usage policy that will apply and this will be advised as part of our line audit.
**This a special reserved rate for the clients that have their Mitel support contracts with 4Sight or are in the process of moving their support to 4Sight. It is a time restricted offer designed to bring support and line provision under one roof where we can offer a more effective converged service wrap and fault resolution. This is a new billing customer exclusive offer that has offer timescale limitations due to commercial constraints.