- DECT is the Digital Enhanced Cordless Telecommunications standard, defined internationally and used by most home cordless phones to link a handset to its base station.
- A cordless phone connects to the network through its base station, so what matters at the switch-off is how that base station reaches the line, not the handset itself.
- Openreach is retiring the analogue PSTN as part of the all-IP migration scheduled to complete in 2027, after which calls travel over broadband.
- Most existing cordless phones can keep working by plugging the base station into the telephone port on a digital-ready router or into an analogue telephone adapter.
- Ofcom requires providers to give advance notice of the migration and to consider customers who rely on their landline.
Most DECT cordless phones will keep working after the PSTN switch-off if the base station is plugged into the router's telephone port or an analogue telephone adapter rather than the old wall socket.
Last reviewed: June 2026
What DECT actually is
DECT stands for Digital Enhanced Cordless Telecommunications, a radio standard that lets a handset communicate wirelessly with a nearby base station. Almost every cordless home phone sold in the United Kingdom uses DECT, which is why a single base can support several handsets dotted around the house. The handset talks to the base over a short-range radio link; the base then connects to the telephone network on behalf of all the handsets registered to it.
The important point for the switch-off is that DECT itself is just the link between handset and base. It does not care whether the call ultimately travels over copper or over broadband. So the question is not really about the cordless handset at all. It is about how the base station connects onward to the network, and whether that connection survives the retirement of the analogue line.
How cordless phones connect to the PSTN today
In a traditional setup, the base station has a telephone cable that plugs into the master socket on the wall, which carries the analogue PSTN line into the home. When a handset places a call, the base seizes that analogue line and dials out over copper. Everything the household has used for years sits on top of that single physical connection.
When the PSTN is withdrawn, the analogue dial tone at the wall socket disappears. A base station left plugged into the old socket then has nothing to dial out over. This is the moment people worry their cordless phones have become useless, but in the great majority of cases the handsets are fine and only the connection point needs to change. The signal now arrives over broadband, so the base needs to be connected to the equipment that delivers a voice service over that broadband.
DECT phone PSTN switch-off compatibility options
There are a few ways to keep existing cordless phones working once the line has migrated, and the simplest one usually applies. The table below summarises the common scenarios.
| Scenario | What you do | Hardware needed | Notes |
|---|---|---|---|
| Router has a phone port | Plug base into the router's telephone socket | Existing cordless phone | Most common; provider often supplies the router |
| Router has no phone port | Add an analogue telephone adapter | ATA plus existing phone | ATA converts the analogue signal for VoIP |
| Buying new equipment | Use an IP-DECT or VoIP cordless phone | VoIP-capable base station | Connects directly to the network without an adapter |
| Power-cut concern | Add battery backup or keep a mobile | Backup unit for router and base | Broadband phones need mains power to work |
The single biggest practical difference from the old system is power. An analogue line carried a small current down the copper, so an old corded phone worked in a power cut. A cordless DECT phone always needed mains power for its base, and once the line is delivered over broadband the router needs power too. Households that rely on the landline should think about a backup arrangement or a charged mobile for emergencies.
What to check before the migration
Before the line is switched, it is worth confirming three things. First, whether the new router supplied by the provider has a telephone socket, often labelled for a phone, into which the cordless base can plug. Second, whether the cordless phone is old enough that buying a modern set might be simpler than adding adapters. Third, whether anyone in the household depends on the line for telecare or medical alarms, because those need separate attention rather than a straightforward base-station move.
For most people the upgrade is genuinely as simple as moving one cable from the wall socket to the router. The handsets, the phonebook stored in them, and the way calls are made all stay the same. The change is in where the base plugs in, not in the cordless phones themselves, which is why a working DECT set rarely has to be thrown away just because the PSTN is being retired.
Resilience, signal and what changes day to day
Beyond the physical move of the base station, the most meaningful difference is how the phone behaves when something goes wrong. On the old analogue line, the copper pair carried enough current to keep a simple corded phone working even when the house lost mains power. A DECT cordless phone never had that resilience, because its base always needed a mains socket, but once the line itself is delivered over broadband the router becomes another point of failure too. If the power goes off, the router and the base both go silent, and the only way to keep a voice service available is to fit battery backup to the broadband equipment or to keep a charged mobile phone to hand for emergencies.
Coverage inside the home is the other consideration that occasionally trips people up. DECT handsets communicate with their base over a short-range radio link, and that range is unchanged by the switch-off. What can change is where the base now has to sit, because it must be near the router rather than near the old master socket. In a larger property this may move the base to a different part of the house and reduce the area a handset can reach, so it is worth checking that the rooms where the phone is used still get a reliable signal once the base has been relocated. Where coverage is marginal, a repeater or an additional registered handset closer to the base can restore it.
It also helps to think about the broader set of devices that share the home phone line, because the cordless base is rarely the only thing plugged into it. Caller-display units, answering machines built into the base, and any monitored alarm or telecare pendant may all expect the same analogue dial tone the base once used. Most of these continue to work once the base is connected through the router or an adapter, but a monitored alarm or a personal care alarm should always be flagged to the service provider so its migration is handled deliberately rather than assumed. Checking the whole collection of connected equipment before the line is switched avoids the situation where the phone itself works perfectly but a less obvious device that depended on the same socket has quietly stopped functioning.
Frequently Asked Questions
Will my cordless phone work after PSTN switch-off?
In most cases yes. The cordless handsets are unaffected; what changes is where the base station connects. Plugging the base into the telephone port on a digital-ready router, or into an analogue telephone adapter, lets the existing phone keep working over the new broadband-based service.
What is a DECT phone?
A DECT phone is a cordless phone that uses the Digital Enhanced Cordless Telecommunications radio standard to link the handset to its base station. The base connects to the network, and one base can support several handsets, which is why DECT is used by most home cordless phones in the UK.
Can I use an adapter to connect my cordless phone to VoIP?
Yes. If the router has no telephone socket, an analogue telephone adapter, known as an ATA, converts the analogue signal from the base station into the digital form needed for a VoIP service. The cordless base plugs into the adapter, which in turn connects to the network.
Do I need to buy a new phone for VoIP?
Usually not. Most existing cordless phones continue to work by plugging the base into a router phone port or an adapter. A new VoIP-capable or IP-DECT phone is only necessary if a household prefers equipment that connects directly to the network without any adapter.
What is an ATA adapter?
An ATA, or analogue telephone adapter, is a small device that converts the analogue signal from a standard phone or cordless base station into the digital VoIP format used over broadband. It lets older analogue equipment keep working after the analogue line has been withdrawn.
