Are you prepared for the PSTN telephone network switch off? It’s now under three years until BT turns off the Public Switch Telephone Network (PSTN), which requires all businesses to make the move to internet-based voice services like (VoIP) Voice over Internet Protocol . Very few businesses are aware of what it means for their day-to-day operations, despite this being the biggest digital transformation in communications since television’s digital switch over.

What is the PSTN telephone network?

Old fashioned Telephone
Old Fashioned Telephone PSTN

The PSTN has formed the basis of the UK’s telephony infrastructure since the first phone lines were used back in 1875. It connects calls by transmitting analogue voice data and also supports digital services such as the Integrated Services Digital Network (ISDN). If your business phone is a landline, it will use the PSTN. It’s also used for older broadband connections through the Asymmetric Digital Subscriber Line (ADSL) system, which uses the same copper wires that form the PSTN to deliver internet connectivity.

Why is the PSTN Telephone network being switched off?

Back in 2015, BT Openreach announced it will be switching off the PSTN in December 2025. The equipment that makes up the network is ageing, and reaching end of life. Maintaining the network is becoming increasingly challenging and new, digital alternatives are emerging, making the PSTN surplus to requirements.

Now, it’s possible to use the internet for the telephony services the PSTN previously provided. So, from December 31, 2025, the PSTN will be completely switched off and all businesses will need a digital, internet-enabled phoneline to replace their landline and continue receiving and making calls.

Where are we now?

In 2020, BT began the gradual PSTN switch-off. There are currently two pilot locations in the UK where all PSTN-enabled services are no longer available to purchase: Salisbury and Mildenhall. The termination of sale of these services is known as the ‘stop sell’. Openreach is gradually expanding the stop sell across the UK and hopes to complete the national stop sell by September 2023. After this date, it won’t be possible to purchase a traditional landline or even change the location or package of an existing one.

Openreach usually issues areas with a 12-month notice period before it implements a stop sell, so businesses have time to make alternative arrangements. But due to the magnitude of the switchover, it’s important to get ahead and consider making the switch sooner rather than later to ensure continuity of service.

What does this mean for my business?

The PSTN switch off means that businesses using a traditional landline or office phone will need to find a new internet-based voice service. But there are also consequences for broadband connectivity. If your current broadband connection operates using the ASDL network, you’ll also need to switch your broadband over too.

Voice alternatives

The internet-based replacement of the landline is known as Voice over Internet Protocol, or VoIP. It transmits voice calls over the internet by converting the audio at one end of the connection into digital data packets, which are transmitted via the internet to the other end of the connection where they are converted back into audio files. This results in almost instant, internet-enabled phone calls.

Not only does VoIP perform all of the same functions of a traditional landline system, but it also offers other benefits that can help businesses prepare for the future of working practices. It’s completely scalable, allowing businesses to add or remove connections in just a few minutes, and accessible through any device connected to the internet. This gives firms greater flexibility to take calls from anywhere and everywhere, not just a designated workspace.

Broadband alternatives

While ultra-fast full fibre is the alternative to ADSL broadband, BT Openreach is still rolling it out, and once 75 per cent of an area has access to full fibre broadband, the ADSL connections will be no longer available to purchase.

So, businesses operating in these areas will need to make the switch. The ultimate goal is to make all internet connections through full fibre, known as Fibre to the Premises (FTTP). But in areas where FTTP is not currently an option, there are interim solutions available. Fibre to the cabinet (FTTC) uses fibre optic cables for connectivity up to the green street cabinet, but then relies on the copper wires from the cabinet to a business.

There’s also Single Order Generic Ethernet Access, or SOGEA. It’s similar to FTTC but comes without a landline, which is a typical requirement for FTTC installation. Opting for SOGEA if full fibre isn’t available is therefore the most forward-thinking solution as, with no landline option available, you’ll also need to select a VoIP phone system to make and receive calls.

The end of the road for the PSTN will switch up telecoms for all UK businesses, but it doesn’t need to be daunting or a hassle. Getting ahead and switching over to internet enable services like FTTP where available, SOGEA and VoIP will ensure operations continue to run smoothly, future-proofing your business for years to come.