What is SIP?

Session initiation protocol (SIP) establishes a voice or audio media session over the telephone.
SIP works by first establishing the call session, managing the signal over the internet during the session and then finally terminating the session.

Why is SIP important?

In 2025, BT will switch off the ageing ISDN telephone network and businesses still using it will be forced to migrate to more modern technology such as SIP. You really don’t want to be one of those stragglers, scrambling to implement a brand-new system before your line goes dead and you’re left with no working telephony at all.

What’s the problem with ISDN and why would you want to change to SIP?

In a word, the ISDN network is increasingly unfit for purpose. This copper-based infrastructure was implemented in the 1980s and designed for making calls, not transferring data. The system is now creaking under the weight of all the files, photos and videos we send every single day.

But it’s not just that ISDN can’t cope. It’s also that far better alternatives are now available, and with such focus on remote working, more modern, IP-based calling solutions help your team communicate and collaborate far more efficiently.

What are the key benefits of SIP over ISDN?

SIP carries voice and data over the same pipeline, which opens up all sorts of possibilities for business communications. ISDN can also carry data, but not in a way that allows for efficient multi-channel communications. SIP can easily handle voice, video and conferencing, in one system. It can also integrate seamlessly with unified communication (UC) solutions.

SIP is highly flexible, letting you add and remove lines quickly and easily, and it both improves call quality and lowers costs. No significant capital expenditure is required to install SIP, and there are no ongoing maintenance costs. It’s pretty much the industry standard at the moment, and the obvious choice for businesses looking to replace ISDN. In fact, you may not even have to change your current infrastructure; SIP is a virtual product, compatible with most traditional on premise PBX equipment.

What do you need to consider when choosing your SIP solution?

Number of concurrent calls

When determining how many SIP channels your business requires, it is imperative that you consider the number of concurrent calls (this includes both inbound and outbound) that your business may need to handle at any one time.

Number of minutes

You should give consideration to the number of calls that your business makes and the length of these calls, we can offer many bundle packages with our SIP channels but we also have the flexibility to offer bespoke tariffs that may end up being cheaper if your business is likely to have a very low volume of calls.

Number of new numbers

As part of the move to a new provider, you may wish to consider provisioning some new numbers, remember all of this can done with minimal set-up costs and comparatively cheaper on-going costs.

Porting of existing numbers

The porting process is a really key and important stage of the process as your business cannot afford to have any sort of lengthy down-time. Porting is on the whole a simple process but can take up to 30 days.

The Jutel Added Value for your Business Telecoms


As a specialist business telecommunications provider, we are large enough to offer a high quality, bespoke level of account management and support, yet small enough to remain agile and responsive to our customers’ needs.

We do not have call centres, phone calls are answered by people who know and care about your business, and we are always available out of hours immediate technical support.

Account Management

We offer proactive daily account management and will flag / automatically bar any users who are incurring spend. We also provide monthly account reviews on your business telecom fleet and in turn provide insight and recommendations on how to best save money as standard.

Online Billing

We have developed our own billing platform, ATOM, so you could say we are the billing experts when it comes to telecoms!

The most important benefits of the billing platform for your business telecoms fleet are:

  • Access 7 days a week, 24 hours a day – log on at any time to view your account from any device.
  • Up to date information – in addition to your monthly invoice you will be able to track your usage and spend throughout the month giving you a preview of your upcoming invoice before it has even been generated.
  • Alerting functionality – you can set your own individual spend and usage limits so that you can be alerted if you hit certain thresholds.
  • Easier to interrogate bills – you can really quickly filter your usage to find particular calls or to see what charge types you are incurring costs on.
  • GDPR Compliant – your information and data is completely secure within our portal.
  • Self-service functionality – you will have the ability to amend your address and usernames within the system without the need to phone or e-mail us. With 24/7 access you can complete these changes at your own leisure or you can still speak to us if you need any assistance.

Networks we work with

Contact Us


0333 00 69696


Bourne House,
475 Godstone Road,
CR3 0BL.