The PSTN Switch-Off:
What to Do Before 31 January 2027

What is actually being switched off

The PSTN (Public Switched Telephone Network) is the copper-based analogue voice network that UK landlines have used for a century. ISDN2 and ISDN30, the digital lines most office PBXs connect to, ride on the same infrastructure. BT and Openreach originally planned to close it at the end of 2025. In May 2024 the deadline moved to 31 January 2027, and in 2026 Openreach repeated that there is no further extension.

Broadband is not switching off. The copper pair into your building may stay for data (on FTTC) or be replaced by fibre (FTTP). What ends is the ability to make and receive calls over that copper using an analogue dial tone.

Openreach said in mid-2026 that around 1.2 to 1.5 million lines, including roughly 350,000 business premises, had still not migrated. Lines not moved by the deadline will not be hard-disconnected on the day; they are moved to a temporary emergency-voice-access service with limits, which is not a substitute for a working phone system.

Who is affected

• Any business with a traditional landline number on an analogue line, including single-line shops and home offices.
• Any office with an on-premise PBX connected over ISDN2 or ISDN30.
• Anything else that dials over the analogue line: intruder and fire alarms, lift emergency phones, door-entry panels, older card terminals, fax machines, telecare devices and some CCTV.
• Businesses that already use a VoIP phone system but still keep a copper line "for the alarm" or "for the fax".

A six-step plan

1. List every line. Walk the building and check every socket, the alarm panel, the lift and the card terminal. Ask your current provider for a list of the lines on your account.
2. Decide what each line becomes. Voice lines move to a cloud phone system; alarms and lifts need an IP or mobile-network replacement from their maintainer; most faxes can become email or an online fax service.
3. Choose a cloud phone system and sign up. A hosted system needs no on-site PBX: the apps run on your existing computers and phones, and you can add SIP desk phones if you want handsets.
4. Port your numbers. Give the new provider your numbers and a Letter of Authority; they raise the port with your current provider. Keep the old service active until the port completes.
5. Check your broadband and power. Calls now depend on your internet connection, so confirm bandwidth (a voice call needs roughly 100 kbps each way) and consider a 4G/5G backup or a UPS for critical lines.
6. Cancel the copper lines only after the port date has passed and you have made a test call from every device.

How AymexConnect fits

AymexConnect is a hosted business phone system, so there is nothing to install on site: the desktop, mobile and web apps work on the devices you already own, and compatible SIP desk phones can be added to any user on Professional and above. We port your existing numbers in, and until the port completes your old line keeps working. Plans start at £8.95 per user per month, Professional at £17.95 includes unlimited UK landline and mobile calling, and the 30-day trial lets you test the apps before you move anything.