Guide · Telecoms
The PSTN switch-off: what it means for your business.
The UK’s old analogue phone network, the PSTN, is being switched off in what is often called the big switch-off, and BT expects everyone to have moved by 31 January 2027. Anything still on a copper phone line needs a plan before then.
By the PC1 telecoms team · Updated November 2026
What is happening
Copper phone lines are being replaced by digital ones.
The PSTN (public switched telephone network) is the analogue copper network that has carried UK phone calls for decades, along with ISDN lines that run over it. Openreach is retiring it, and calls move to digital lines that run over broadband (VoIP). BT expects customers to have moved off the analogue network by the end of January 2027.
Business lines have no emergency fallback, so anything still connected to an old line when it is switched off can simply stop working.
What to check
More than phones plug into a phone socket.
- Office phone lines, ISDN2 and ISDN30.
- Intruder and fire alarm lines.
- Lift emergency phones.
- Card machines on a phone line.
- Door entry systems, fax machines and franking machines.
- Old phone exchanges in a cupboard.
Our free line audit lists every number, line and device, and the date each needs moving. See 8x8 phone systems.
Your options
Three ways to replace a business line.
| Option | What it is | Best for |
|---|---|---|
| Hosted phone system (hosted VoIP) | Your numbers move to a cloud phone system such as 8x8; desk phones, laptops and mobiles all ring | Most businesses |
| Microsoft Teams calling | Normal phone calls inside the Teams app, using 8x8 numbers | Businesses already on Microsoft 365 |
| Digital voice line | A single digital line for one phone or device | Very small sites and single lines |
PSTN switch-off questions
What people ask before switching.
When does the PSTN switch off?
Can we keep our phone numbers?
Will our alarm still work?
What does it cost to switch?
Free line audit
Find out what stops working before January 2027.
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