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So you have heard that BT is planning to switch off its ISDN network in 2025 and you are wondering how that will affect your business and what you should do about the switch off.

Fortunately, here at Criterion Systems, business communication and telephone systems are our speciality and we have created this handy guide to help you through the 2025 ISDN Switch Off.

What Exactly is Happening?

In 2015 BT announced that is was phasing out its PSTN and ISDN networks, that are used for voice calls, in favour of more advanced IP voice services. This gradual phasing out of the older PSTN and ISDN systems is due to start in 2020, when BT will cease taking any more ISDN orders, leading up to 2025, the proposed date of the ISDN Switch off.

If your business makes use of or provides PSTN or ISDN lines or networks, then this switch off is going to have a significant effect on you. By 2025, businesses will be forced to find and use an IP-based system for all of their telephony needs.

What is ISDN?

ISDN (Integrated Services Digital Network) is a telephone network that allows for both voice and data services to be delivered over digital lines simultaneously. Effectively it’s what carries your telephone conversations when you talk on the phone and your data when you use the internet. It was launched in 1986 to migrate old landline technology over to digital.

ISDN was a great system when it was launched as it could support an analogue phone line and early video-conferencing systems, something extremely useful for businesses at the time.

Unfortunately for ISDN, the introduction of new broadband internet access connections has made it an outdated legacy system. It is still used by many smaller businesses or as a backup phone system in the event the main line fails.

What is PSTN?

PSTN (Public Switched Telephone Network) is the familiar landline telephone system that has been used since the invention of the telephone. It was set up for analogue voice communication and was the most reliable way of making voice calls. ISDN allowed the digital transmission of voice and video using the traditional PSTN network.

What is the difference between ISDN and PSTN?

PSTN is the older technology that uses copper wires to send analogue voice data over circuit-switched phone lines. ISDN built upon that technology and moved the transfer of voice and video over to digital.

Why are BT phasing out ISDN and PSTN?

The short answer is that both ISDN and PSTN are old and outdated legacy technologies that have some serious drawbacks and maintenance costs. The infrastructure behind ISDN is essentially the same design that the early telephone networks of the late 1800’s used, with some significant improvements over the years of course. The cost of maintaining such an old infrastructure is continuing to increase and with much better alternatives available, it doesn’t make sense for BT to continue.

ISDN has also failed to keep pace with the demands of businesses and can only support speeds of about 128kbps, which is well below the speeds of modern broadband which is around 16 Mbps. Over half of UK businesses have already made the switch from ISDN to an IP system.

BT has also invested heavily in VoIP, one of the systems that are meant to replace ISDN, so it doesn’t make sense for BT to continue to invest in what is an obsolete system. By moving everyone over to an IP service, BT will be able to focus their resources and investment into a technology that will continue to meet the demands of businesses in the future.

What is BT going to replace ISDN with?

BT is planning on moving its network to be based on IP, which unlike traditional solutions, does not run on copper lines and only requires an active internet connection to use. There are two options involving IP; hosted VoIP and SIP.

Both are cloud-based telephony solutions and have been made readily available to most businesses thanks to the recent investment in the UK communication network and the new fibre infrastructure.

40% of the UK market has already recognised that switching to a VoIP provides them with a variety of key benefits.

What is VoIP?

VoIP (Voice over Internet Protocol) technology has transformed traditional telephone services, superseding ISDN systems with cheaper, more advanced solutions. VoIP is the method of making phone calls over the internet or an internal network. Also known as an internet telephone, the use of this method of communication has become mainstream – removing the need for old fashioned and expensive to maintain phone lines at your premises.

VoIP Features:

  • Cost-effective (free and cheaper calls, plus no more expensive line rental)
  • Better features and flexibility (integration, greater control and analytics that transform your business communication)
  • Higher resiliency (stay connected, ensuring business agility and productivity)
  • Greater flexibility (plug into your network from anywhere with Wi-Fi)
  • An Improved call quality (HD audio)

What is SIP?

SIP (Session Initiation Protocol) and SIP trunks is an on-premise solution for a telephone system that allows you to connect your phone system to the public phone network via IP data services rather than traditional fixed line telephone services, such as PSTN and ISDN. SIP offers improved scalability and functionality through a single internet connection which allows you to divide bandwidth between voice calls and data. Being 30-50% cheaper than traditional telephone lines, SIP is a popular choice.

SIP connectivity is now standard on most modern phone systems and available as a simple upgrade to legacy systems. This allows you to maintain your investment on your existing system and still benefit from the flexibility and cost-savings of SIP services.

SIP Features:

  • Reduced costs (SIP includes free landline calls and other lower priced options)
  • Scalability (individual SIP endpoint connections can scale from 2 to 30 channels)
  • Business continuity and reliability (Criterion Networks provide dedicated servers for your phone system to connect to as well as running carrier-grade software for superior reliability)
  • An Improved call quality (HD audio)

How to prepare your business for the BT ISDN switch off

2025 might seem like a long way off yet, but you will be unable to purchase a new ISDN system or amend your current system, after 2020. If you currently have a traditional ISDN or PSTN based system now would be a good time to begin researching a more advanced alternative. If you are in the position where you haven’t got a business telephone system yet, then you are in a perfect place to start with a new IP based telephone solution. This means that you will be able to avoid the setup costs that come with an ISDN system.

If your current ISDN phone contract is up for renewal soon, then now is the time to start researching your options to swapping to a Voice Over IP system or SIP technologies.

There is no good reason to wait

Waiting until the switch off date to update your telephone system might not be the best idea for your business. Closer to the date could cause a shortage of engineers as they struggle to meet the demand of the many businesses that still have an ISDN system, and could cause a delay in your upgrade.

You would also be missing out on all of the benefits to your business that come with VoIP or SIP technologies. So if you haven’t already enjoyed the business benefits of switching from ISDN, why wait?

Criterion Systems offer a FREE (no-obligation) assessment of your current set-up to determine your needs and can help you select the right telephone system for your business. We provide competitive business phone systems, full technical support, maintenance back-ups, advice and staff training. We keep you in touch with your customers and save you time and money on your telephony needs. To book your free assessment please get in touch.