Since BT have announced that from 2020, you will not be able to purchase new ISDN services, as it targets the 2025 shutdown of the network, many questions are naturally being asked.  Will they really do it? What needs to be in place before the switch off?

In 2015, BT boldly announced its intention to switch off its PSTN and ISDN networks by 2025. Many said this was a clever move to ensure the market began to embrace IP as the standard protocol for all communications services, it was important for  the UK’s underlying largest telco operator to declare its intentions to remove the legacy products from its network, while giving customers a whole decade to make the switch (if they haven’t done so already).

What does this really mean to the average SME business in the UK?

Firstly, let’s start by looking at what PSTN and ISDN are. PSTN is the same phone line most people have at home, whereby analogue voice data travels over circuit-switched copper phone lines. While it may have evolved over the years, PSTN lines are very, very old technology, operating on the same fundamental principles as the very first public phone networks of the late 19th Century. It is worth noting that PSTN does not just power voice, as asymmetric digital subscriber line (ADSL) and fibre-to-the-cabinet (FTTC) both operate on it – or more commonly known as broadband. As of yet BT have not suggested any replacement technology for these, so one can assume that BT’s planned obsolescence of PSTN applies to voice only in this instance.

ISDN, by contrast, is a much younger technology, which hit the market in the late 1980s. ISDN allows both voice and data services to be delivered over digital lines simultaneously (ISDN stands for Integrated Services Digital Network). When it launched, ISDN was ideal for businesses, as it could support early video-conferencing systems at the same time as well as providing a stronger feature stack (compared to analogue lines) for telephone systems/PBX’s.  Before the days broadband, it could also offer the fastest internet access available (128 kbps). The evolution of low cost IP connectivity first demoted ISDN to a voice only network for the connection of PBX’s to the PSTN voice network. The real transition to VoIP (away from ISDN) was the increased reliability of broadband, coupled with the lower cost of Ethernet leased lines.

So, if BT is killing this old technology, what’s replacing it?

In a nutshell, BT is moving its entire voice network to voice over IP (VoIP). VoIP is hardly ‘new’, and its been around much longer than you think. VoIP has been a proven platform for voice for some time now. It works, but only if deployed correctly. If your business has renewed its telephony sometime in the last few years, you may have been told about it (but don’t be surprised if you haven’t, since IP is a whole new game that has been growing steadily in the background, with more and more businesses realising the benefits demonstrated by the early adopters).

Market uptake took a major leap forward with the availability of fibre broadband a few years ago. Early ADSL2+ connections were just not suitable for VoIP, and many voice resellers got cold feet, as their clients’ (who took the plunge to move away from ISDN to VoIP) experienced outages and poor voice quality. Increased network bandwidth has pretty much eradicated this, but many seasoned VoIP experts are keen to ensure VoIP traffic is transmitted over higher quality leased lines (rather than broadband).

VoIP has many advantages over PSTN and ISDN too; it is much quicker to provision new lines, you can reduce your line rental due to needing fewer physical lines, and it is vastly scalable and flexible – for example you can redirect calls to different parts of the country at the flick of a switch, or have a single phone number follow you around the world irrespective of where you’re working. Have dial codes from not just any UK city, but also, any country of the world. One system really can serve your global workforce.

Why is BT turning off the ISDN network?

You don’t still have an iPhone 3GS do you? Same reason, but on a much, much bigger scale. Also, maintaining multiple legacy networks is very expensive for BT. By converging all services – voice, data, video, and even broadcasting – to the IP protocol, BT only has to maintain one network, not several.

It is also worth bearing in mind that 2025 might not be Doomsday for ISDN. The date is not set in stone. It is BT’s intention to stop selling PSTN and ISDN by 2020 and shut it down completely by 2025 – but this is assuming it has managed to switch all customers over to IP services before then. This means that a viable alternative must be available to everyone well before 2025. For many businesses today, ISDN is still the best they can get. According to Ofcom, there are 33.2 million fixed landlines in the UK (including ISDN), and approximately 7.6 million of these belong to businesses. BT will not turn them off before they have an alternative firmly in place.

What should you do?

Well, even if 7 years (at the time of writing this) seems a long way off, consider this. BT will reduce investment in looking after this network. This means that faults might take longer to resolve. New staff won’t have the experience, and the old guard who built and run the network will soon be pensioned off. The advice is simple…..bite the bullet and get on with the change. Our advice:

1- VoIP is only as good as your Internet connection. Yes, fibre broadband will technically work, but it doesn’t have the same SLA’s (service level agreements) as your current ISDN. Of course, budget/price is key, but so is uptime of mission critical business services.

2- Once you know your Internet connection is suitable, then find the right technology vendor. This could be an on premise IP PBX (connecting to SIP trunks), or it could be a Cloud PBX (typically rented on a per user per month basis). There are literlaly hundreds of options – a good reseller will talk you through your options.

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