SIP Trunks

SIP Trunks

What are SIP trunks?

SIP Trunks (Session Initiated Protocol) are connections that link the Phone System (PBX) at your business premises to the Public Telephone Network (PSTN).

These SIP connections are delivered via an IP or Assured Broadband connection (FTTC, Leased Line Circuit) meaning call quality is reliable. There is a reduced risk of downtime during an event or disaster, which could otherwise impact your business. SIP Trunks are a great alternative or addition to Digital and traditional ISDN2 or ISDN30 channels.

Why should I change to SIP?

ISDN and PSTN as technologies are being phased out by BT. They are planned to be switched off completely by 2025. This means that customers now need to consider upgrading their system, or moving to a hosted system.


What are the business benefits of SIP?

Monthly Line Rental Cost Reduction

Compared to IDSN, SIP trunking can help reduce line rental costs, call costs and help save your organisation money by taking away unnecessary ISDN lines.


10 IDSN30 Channels – Monthly Rental of £13.50 (Per Channel) – Total of £135.00


10 SIP Trunks – Monthly Rental of £4.00 (Per SIP Trunk) – Total of £45.00


Grow your business quickly

SIP’s number one advantage is that it’s completely scalable – you can scale your telephony up or down with ease. Perfect if you are moving, upsizing or downsizing and want to keep your existing numbers. This is beneficial for businesses expecting growth, and those with seasonal-related busy periods when you need to up your telephone resources to manage increased orders, sales and enquiries.

Become a truly flexible business

SIP is an extremely versatile form of telephony. You can easily manipulate outbound numbers – ideal if you’re moving office and wish to keep your existing telephone numbers. You can set up non-geographic numbers easily (0330, 0845, 0800) and a series of geographic numbers for those companies wishing to have a town, city or county based presence – all routed to the same location. Calls from a mobile phone under a specific number, regardless of the user’s location, are also possible.

Rationalise your telephony across multiple sites

If your business has multiple sites, then you can use SIP Trunking to help you rationalise the number of PBX’s you need to maintain, including any maintenance costs associated. By reducing the number of ISDN connections into individual PBX’s at each site, you can help centralise and distribute calls more effectively and help with any disaster recovery planning at the same time.

More reliable and resilient

SIP is flexible and instant so you can be confident that you’re prepared for any situation. You can put in place a disaster recovery plan, set up backup facilities and ensure business continuity. Calls can be rerouted instantly in the event of an emergency and multiple DDI’s can be pointed anywhere you wish without having to refer to a middle man first. Some companies choose to use SIP Trunks alongside their existing ISDN infrastructure to make sure that one acts as a fail-over to the other. However you choose to deploy SIP it serves to make a business much more resilient, giving you peace of mind that business continuity will always be possible.

How does it work?

What are SIP trunks?

Your company’s voice traffic is carried over an Assured Broadband or a Managed Internet connection using SIP Trunks. This connection is specifically designed to carry voice traffic, which means high quality of calls. The connection is essentially an end-to-end service and comes with availability guarantees, voice channel guarantees and voice quality of service.
For SIP Trunking to be enabled your existing phone system and PBX hardware needs to be compatible. We can assist with this, please do not hesitate to ask.
The SIP Trunks that we provide are compatible with most of today’s leading phone systems and PBX brands throughout the UK and Europe. This means you can easily take advantage of the many benefits to be had from moving to a SIP trunking model.