What is The PSTN Switch Off?

Now, this is a hot topic within the broadband and comms world at the moment and has been for the past three years plus. So first, let’s understand all the different phrases and buzz words used around this industry change.

Below are the different phrases and the number of monthly searches each phrase gets on Google. This is the best way for us to break down all the different wording around the big switch-off.


bt isdn: 50
bt isdn end of life: 50
bt isdn lines: 50
bt landline 2025: 50
bt landline switch off: 50
bt openreach isdn switch off: 50
bt openreach pstn switch off: 50
bt pstn: 50
bt pstn 2025: 50
bt pstn line: 50
bt switch from copper to fibre: 50
bt switch off isdn: 50
bt switch to digital phone: 50
bt switching off analogue: 50
bt switching off landlines: 50
bt to stop landlines: 50
bt turning off phone lines: 50
business pstn: 50
copper switch off 2025: 50
bt big switch off: 50
bt isdn switch off announcement: 50
landline switch off 2025: 50
2025 analogue switch off: 50
2025 big switch off: 50
2025 isdn switch off: 50

pstn switch off: 5000
bt switch off: 500
landline switch off: 500
isdn switch off: 500
bt analogue switch off: 500
bt pstn switch off: 500
pstn switch off dates: 500
bt isdn switch off: 500
bt copper switch off: 500
pstn isdn switch off: 50
bt switch off 2025: 50
analogue phone line switch off: 500
2025 switch off: 50
isdn switch off 2025: 50
openreach switch off: 50
analogue telephone switch off: 50
bt 2025 switch off: 50
openreach isdn switch off: 50
pstn shutdown: 50
isdn lines switch off: 50
openreach pstn switch off: 50
the big switch off 2025: 50
2025 phone switch off: 50
2025 pstn switch off: 50

Right, so now we know all the different phrases, let’s begin.

What is PSTN: PSTN relates to a single phone line. You can get different types of traditional phone lines. All homes will use a PSTN line for telephone calls and broadband (unless you have full fibre, we will explain more about that in the article). Then for businesses, you can have a PSTN Line or ISDN2 line or ISDN30 line. A PSTN line for most companies is not enough as it only allows for one concurrent call. Now of course, with the Full Fibre revolution, many companies won’t have a PSTN line at all for broadband, they may have a Full Fibre service.

What is ISDN: Like a single line, apart from there’s multiples. ISDN comes in two forms: ISDN2 and ISDN30. ISDN is only used for business premises because it means you can have multiple concurrent calls at once. Unlike PSTN, where there is only one line coming, meaning you can only have one call at a time. For companies that take multiple calls at once, PSTN is not enough. That’s where ISDN comes in. ISDN2 comes in pairs; you can have eight pairs of ISDN2, for example. Which means you have 16 lines. So, for example, if 12 employees were making outbound calls on a sales campaign, the company still had 4 lines available for inbound calls. ISDN30 is the same but with blocks of 30 lines.

Broadband and Phone Lines: Carrying on, traditionally, we used phone lines for broadband. In the UK, we have a large copper network which was originally laid for calls to be made. Before mobile phones, calls needed to travel over a wire, so we laid hundreds of thousands of miles of copper cable to carry those calls. Now, when broadband first launched, we needed a solution to transmit the data. We needed to bring a signal into our homes and businesses, then out to the internet. Guess what infrastructure we used? You got it. We used the telephone network that was already laid.

Short overview of VOIP calls: VoIP stands for Voice Over Internet Protocol. To put this into simple terms, it’s a telephone call that works over the internet. Now, you can have a “VoIP” call at home and of course, for business. The reason why more people are becoming familiar with VoIP is due to the migration to full-fibre broadband (plus, companies who sell VoIP services will most likely have a cold-called you to upgrade you). As mentioned above, calls would traditionally run over the copper network. But, if you have a full fibre connection, you no longer have copper coming into your premises, so the calls need to go over the internet instead. For home users, many ISPs are providing adapters or configuring routers to be able to connect to traditional handsets.

Businesses will be far more used to VoIP. It’s a much more cost-effective way to use the phones within your company. Large companies need a telephone system to deal with inbound and outbound traffic more efficiently and add features like call recording, menus when people call in, call analytics, voicemail etc. etc. Now, before VoIP, this was all handled on an onsite PBX (telephone system which sat in your comms room). Now, however, those chunky telephone systems are being removed and replaced for a cloud-based system. So, you as the business, would never actually see any chunky hardware creating all of these clever features. You just have a desk phone connected to the internet or a desktop application to handle the calls.

What is SIP? It’s how calls are made over the internet. If you have an onsite telephone system (PBX), or a cloud-based telephone system, you need to be able to plumb in a service to make and receive the calls. Before calls could travel over the internet, we would plug physical lines (ISDN) into onsite telephone systems. Or PSTN lines straight into handsets. Jump forward, now we can make calls over the internet, we need something to “plug” into the systems or handsets. Enter SIP. It allows you to plug physical equipment or cloud-based equipment into a telephone network which operates over the internet. But instead of plugging anything physical in, you just configure some settings in the hardware and give that hardware access to the internet.

So now we know the basics, let’s break down the Switch Off!

When was the Switch Off first announced? Back in November 2017, panic started. Openreach announced the switch off of its traditional telephone network. Now, the panic didn’t start with consumers or businesses. It started with resellers. Resellers are the ones responsible for providing voice services into businesses. Resellers have strong relationships and experience with Openreach and it’s not always positive. So, you can understand why the panic began to set in, knowing that this journey was going to be somewhat painful and the responsibility to educate the companies on migrating to “VoIP” was going to be their responsibility.

What are they switching off and why? The traditional telephone network. Simpler: Calls over the copper network. Eventually, the whole country will be on full fibre, so they wouldn’t have access to the service anyway. So why maintain a network which will be removed? It makes complete sense why they are switching the service off. Other countries have done the same, like Germany, for example.

When will it switch off? 2025. Apparently. Now, the likelihood of this being pushed back will be high. Although companies who sell voice services (ISPs, B2B Resellers, MSPs) are doing everything they can to educate their customers and new customers onto the fact they must start making internet calls ASAP before the switch off, it’s falling on deaf ears a lot of the time. At the end of the day, if you’re not in the industry, why would you care? We need to see more support from Openreach. Whether that’s funding for campaigns (hint hint), or direct campaigns with strong budgets to make consumers aware.

What services will be affected? Voice services. Telephone calls that still operate over the traditional network. It’s just voice. Not broadband.

Will my home be affected? Yes. If you still have a FTTC/Part Fibre product or ADSL2+ product. Read more here about those…

Will my business be affected? Yes. If you still have a PSTN service of ISDN service, you will need to change to a VoIP solution or adapt SIP into your current onsite PBX. For the love of God, do not use one of the big national players when you come to migrate to a new solution. Use a reseller. You get a much better personal service and the cost savings will be far larger. Reach out, and we can recommend resellers in your area.

What is Openreach doing to help educate the nation? Not enough. They need to do more. We would love to see a fund assigned to help resellers and ISPs run dedicated campaigns to let the nation know of this major change. The government should help too, let’s be honest. They’re helping with the migration to full fibre, why would you miss the massive part about services switching off!

So, hope this helps!

Jonny Rae

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