Your Guide to the 2025 ISDN Switch Off

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BT announced all the way back in 2015 that they were going to switch off ISDN by 2025. Well, as 2022 is round the corner, so is the switch off, and there’s no time like the present to start thinking about updating and upgrading your phone systems. If you have no idea what any of that means, then don’t worry! It’s our job to understand the ins and outs of telecommunications, so we have together this guide to help you understand and prepare for the upcoming changes. 



What is ISDN? 

ISDN stands for Integrated Services Digital Network and is a digital transmission used to make phone calls, video calls, and transmit data over PTSN (public switched telephone network). ISDN was brought to the UK in 1986 by BT as a means of replacing old analogue landlines. 



However, in 2015 BT announced they were going to end ISDN services as the technology was becoming outdated and is unable to keep up with the digital demand we are accustomed to today. This, therefore, means that from 2025 onwards, all phone calls will be made over the internet. 


Broadband internet speeds are way faster than the technology that was created in 1986 – obviously – and ISDN can no longer compete with broadband speeds. In addition, more and more businesses want to switch to cloud-based technologies that are flexible and suitable for remote working; IP technology is the best choice to keep businesses happy. 


What’s the replacement going to be? 

So, there are two options for replacing ISDN, VoIP and SIP (tech people love their abbreviations). 



The first replacement option stands for Voice over Internet Protocol and is also known as IP telephony. VoIP works by using a group of technologies to deliver voice communications and multimedia sessions over IP networks. Voice calls are converted into data sets, which travel over the public internet and/or private networks. 



Session Initiation Protocol is a means of initiating and terminating data transfers between different users – it is used in multimedia communications. For example, it is the way you can receive a VoIP call. 


Which should I go for? 

If you are confused about what any of the above means, then don’t worry, we’ll simplify the decision making for you. If you are looking to replace your entire phone system when ISDN is dropped, VoIP is an excellent choice. But, if you want to keep your current system running, SIP is your option.


What are the benefits of switching?

  • Cheaper 
  • Fully featured with new capabilities
  • Improved services such as speed and efficiency 
  • communication – combine calls, messaging and emails into one system
  • Protection – disaster recovery systems with little downtime

Is it easy to make the switch? 

With the right company – yes. You will be able to retain all your numbers and information, and the whole process should take around three weeks! Here at Eze Talk, we are the specialists when it comes to helping businesses make the switch. So once you think you have decided which option would be best for you, you can book us in for a chat to make sure everything will be as you want, and we will start making the switch for you. So you don’t have to worry about any of the complicated stuff! 


As these new systems use virtual phone lines rather than physical lines, SIP is a great on-premise solution for a phone system. Due to the flexibility, speed, quality, and lower costs, SIP trunks are becoming more popular. However, before you make the switch, you’ll need a plan to port your phone numbers – this switches you from one provider to another.


If you would like to understand more about the ISDN switch off, please head to our website to browse our information or call up today to begin switching over. Making the switch now is an ideal time before there’s a mad rush to get everything done before 2025, so you can relax and get used to new systems in your own time – plus start benefiting your business today with upgraded technologies. 

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