BT Announces ISDN Business Telephone Lines To Be Switched Off - 4 Step Checklist

Written by Abigail Park
Telecoms Expert
Everything Voice

Twitter: @everythingvoice
Tel: 0330 055 3570

Since BT made the public announcement that they intend to switch off ISDN lines by 2025, the decline in the market for these types of phone line has become apparent. Communications technology is becoming recognised as a driving factor for improving efficiency and providing a better quality service, and those that are making the transition to a more up-to-date system, are moving right away from legacy ISDN telephone lines.

So…will the termination of ISDN lines affect you?

Otherwise known as ‘Integrated Services Digital Network’, ISDN is a service that delivers broadcast-quality voice and data continuously over public switched telephone wires. In simple terms – it is the phone lines used by businesses.

The reason BT is phasing out ISDN lines is due to the many drawbacks connected with this technology, as well as the development of more advanced options which are today available to businesses of all sizes. In addition to the heavy maintenance costs associated with the lines, running costs are also becoming unsustainable. Launched in the 1980s, whilst the phone lines have been updated since then, their setup and design remains the same.

With an estimated 2 million businesses still operating their telephone system over ISDN, it’s fair to say this change will have a major impact on businesses nationwide. Yet it’s surprising to read that still 25% of businesses aren’t aware of the planned ‘switch-off’, even though it was officially announced in 2014 (according to a study by Talk Talk).

If your business is one of those still using ISDN lines and you haven’t already, it really is time to start to research alternative options and make the transition to a new, more advanced and cost effective solution.

The Process

BT’s plan is to have completely switched off the ISDN network by 2025. They will start to put pressure on organisations to make the transition from 2020, although it is greatly encouraged that any business needing to move to a new solution starts the process now.

Ofcom recently composed a report summarising market and customer insights regarding ISDN lines. They say a crossover point has been reached where more businesses are now moving to alternative solutions, rather than opting for traditional ISDN, showing the signs business leaders are recognising it’s simply not worth investing in new technology which relies on an ISDN infrastructure anymore. This trend will no doubt further intensify as we get closer to 2020 and beyond.

How to Prepare

There are 2 main ways to replace ISDN and we have provided some guidance on what these are as follows:

1. SIP Channels

SIP stands for ‘Session Initiation Protocol’. SIP Channels (or SIP trunking) is a way of making telephone calls over an IP connection (or internet connection). A SIP line is essentially a virtual telephone line. SIP channels can connect to your telephone system in the office, then travel out via the internet allowing you to make calls. They are simple to set up (ideally by an IT professional) and have huge cost saving benefits in comparison to ISDN. For example, most SIP providers (including us at Everything Voice) incorporate UK landlines and mobile calls within a bundle, therefore, eliminating these costs completely. In addition to cost, SIP Trunks provide other benefits such as scalability, quick provisioning and futureproofing. Unlike traditional phone systems, you have the ability to increase and decrease the number of connections you use in line with business needs.

2. VoIP Telephone System

VoIP stands for ‘Voice Over Internet Protocol’. All this means is the voice traffic is carried over an internet connection. VoIP systems can either be hosted within an office or in the cloud. Many organisations are favouring the cloud because it means there’s no requirement for maintenance/support contracts. There are so many benefits to VoIP systems over ISDN that it’s hard to list them all. One majorly raved-about benefit is the cost savings for businesses – infact 96% of UK businesses surveyed in 2017 said they saved between 60%-80%. Another important benefit to VoIP is the simplicity and ease to control the systems. For example, you’ve got a new starter and they need adding to the system – ring up the provider, ask for a new user and this can be set up instantly.

4-Step Checklist – What Next?

If you are considering the option of moving to VoIP, the 4-step checklist below will help you in the process of what you need to be thinking about:

1. Contract

Are you still in contract? And if so, when does the contract end?

If you’re not, then now’s the time to start looking at an alternative VoIP solution. Try this tool to design a system yourself >>. If you’re tied in to a contract, you need to start working towards the earliest date you can exit this agreement, and work towards researching systems that may work for your business in the meantime… This might help >>

2. Profiling your Company

How many users would you need to set up on the new system to start with?

Do they all require physical handsets? What about mobile workers?

There are many pre-built packages out there which are not always going to provide you with a system that is suited to your needs. A good supplier will always listen to your requirements and make customised suggestions based on the information you’ve provided. For example, if you’ve got multiple sites, would you benefit from unified communications to collaborate? Or if you have mobile/remote workers, an integrated mobile app may help?

See all the other features you could select here >>

3. Internet Connectivity

Will your current internet connection support VoIP? What internet connectivity options are available to you?

There are some great government funding options available UK-wide at present, enabling organisations to upgrade their internet free of charge. Check here to see if your business is eligible >>

4. Budget

What’s your budget? How much do you want to save? Do you want Capex or Opex payment options?
There are both on-premise and hosted VoIP solutions available, which can be paid for flexibly to suit your cash-flow requirements.


To start the process and look at which alternative options would work for your business, USE THIS TOOL to design the perfect communications platform and get instant recommendations detailing the benefits of your solution:

Unify Triple Play - 3 steps


More like this