17 July 2018


BT has announced that it will be starting the PSTN & ISDN switch off in 2020 (next year)…

What’s happening?

BT has announced that it will be starting the PSTN & ISDN switch off in 2020 . From this point no new orders will be accepted in some areas while, under the plans, all PSTN, ISDN and copper based broadband lines will be completely ceased by 2025. Read article.

As BTs Open reach’s division supply most of the telecoms industry with these services, their decision affects virtually all UK businesses whatever the name on their telecoms suppliers bill. According to Ofcom there were total of 33 phone lines & ISDN channels as of Q1 2018, so the impact will be felt far and wide. Read article.

Why are BT doing this?

BTs decision is an obvious one when you consider that the principles behind the PSTN telephone network date back to the early 1900s and the ISDN network was introduced in the 1980s to combine voice communications with basic data transmission. Frankly the technology has fared amazingly well for decades, offering reliable standardised services that simply worked. But the world has changed and demand for integrated voice & data services permeates every area of social and business like. It’s simply not feasible for Openreach to operate a legacy high cost network any more than it is for Railtrack to run steam trains alongside HS1.

Preparing for the Switch off

In the immortal words of Captain Mainwaring “DON’T PANIC”. If you have a traditional ISDN/PSTN telephone system, they will continue to work past 2020. You should though be thinking about making the change to an alternative technology well before the cut-off date. Of course if you are moving premises after late 2021 you will be forced to migrate to an alternative technology anyway, as replacement lines will not become increasingly difficult to source. It is worth noting that there is always the risk that maintaining the old ISDN/PSTN network become less of a maintenance priority from Openreach as we approach the cut-off date. At least one large Vodafone ISDN customer was cut off, without warning, during their Vodafone’s own ISDN network consolidation process – the subject of a future blog.

What are the Options?

As with IT, telecoms technology is now standardising on the Internet Protocol (I/P) . The excellent news is that this technology is now maturing very nicely and can offer excellent reliability, cost effectiveness and an array of benefits simply not possible previously, including automatic disaster recovery.

The choice then is really between a Customer Premises Solution (an in house Telephone system) or a Hosted /Cloud based solution. Essentially CPE solutions require virtual I/P telephone lines/channel called SIP Trunks, while Hosted Service integrate the telephone lines and the system as a single unit in the Cloud. The decision between these approaches largely depends the Business’ approach to technology investment namely preferences for CAPEX versus OPEX and managed versus in-house expertise. Hosted services have the in-built advantage of not requiring a separate maintenance contract and are centrally updated with new capabilities added regularly.


Finally recent advances in collaborative working have massively increased the the use of applications such as Microsoft Teams, modern I/P technology now allows these to be integrated in your phone system in a variety of ways. We plan to cover the differences in more detail in a future blog.

Don’t forget the Connectivity

The new features and simplicity of an I/P system is the exciting part and its easy to overlook the Internet connection. However for both Hosted and CPE solution it is a critical element and skimping on this will lead to disappointment, poor quality and endless frustration. A separate dedicated Fibre broadband (VDSL) is the minimum requirement for a stable reliable service, where a smallish number of users is involved. Likewise a £50.00 or “free” router, just won’t cut it. You need a full business grade router, unlikely to cost under £150.00 to £200.00. For larger business and where voice & Internet communications are business critical, a dedicated leased line connection should be seriously considered.

Interface Advantage have been advising on and supplying I/P telephony solution since 2008 and are experts in migrating from legacy technologies to customers of all sizes, do get in touch if you would like further information on the great switch off or your options.

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