Will My Old Phone Work After the Digital Voice Switch?
For most households, the answer is yes. Fresh RNID and BT testing found that a wide range of existing landline phones and assistive devices continued to work on Digital Voice — but very old rotary phones, extension wiring, fax machines and some connected devices need extra checks.
Most normal tone-dialling phones can connect through the router or a compatible Digital Voice adapter.
Most existing landline phones should still work after the move to Digital Voice. BT says a compatible existing handset can be plugged into the phone port on the Smart Hub or connected through a Digital Voice Adapter. RNID and BT also tested amplified phones, DECT cordless phones, corded phones, textphones, alerting systems and answer machines, with all tested combinations working for normal use. The main exceptions are very old pulse-dial or rotary phones, some legacy extension arrangements, fax machines and specialist devices that need separate compatibility checks.
What devices were actually tested?
RNID worked with BT at its Digital Services Lab to test a representative mix of old and new equipment commonly used by people who are deaf or have hearing loss. The work covered both ordinary phones and specialist accessibility equipment.
Common amplified handsets worked with Digital Voice in the tested scenarios.
Digital cordless phones were included in the compatibility testing.
Standard corded handsets were tested for normal calling functions.
Textphone behaviour was checked alongside normal voice functions.
Common alerting equipment used by people with hearing loss was included.
Answer machines worked, although voicemail timing can need adjustment.
RNID says the overall result was positive: all tested combinations of phone and platform worked as expected for typical use, and the most commonly used amplified phones and alerting devices were compatible without special intervention.
The reason this matters now is that the UK’s old analogue phone network is due to be retired by the end of January 2027. Our Openreach copper switch-off guide explains the wider migration from old voice and copper services to digital networks.
Which old phones are likely to work?
Age on its own does not decide whether a phone will work. The important question is how the phone dials and how it connects. A decades-old tone-dial corded phone may work perfectly, while a beautifully restored rotary phone may not because it sends pulses rather than modern DTMF tones.
Five compatibility issues RNID and BT found
The testing was positive overall, but it still found practical problems that could make a phone appear incompatible when the real issue is setup or configuration.
BT’s voicemail can answer before a home answer machine. RNID says the fix is to disable 1571 or change the settings so the home machine picks up first.
Traditional extension sockets are not used in the same way on BT Digital Voice. Extra normal phones can use Digital Voice Adapters, and some multi-phone functions may need hub configuration.
RNID found that differently wired older phones could fail to ring with BT’s original adapter. It says the adapters now being supplied resolve that issue.
RNID observed some incorrect characters, but says the same behaviour also occurs on analogue lines, so it was not treated as a new Digital Voice fault.
RNID did not test fax machines. BT’s own guidance says fax is generally supported but cannot be guaranteed, so a business or household that still relies on fax should test before depending on it.
What happens to my old phone sockets and extensions?
For BT Digital Voice, your normal home phone no longer depends on the old analogue voice service coming through the wall socket. Instead, the phone connects to the broadband hub or a compatible adapter.
BT says an existing compatible handset can connect directly to the phone port on the back of the Smart Hub.
The adapter connects wirelessly to the hub and gives the existing phone a telephone socket elsewhere in the home.
BT says ordinary extension sockets are not supported in the same way on its Digital Voice service. If keeping existing extension wiring is essential, BT advises contacting it to discuss the available options rather than rewiring the system yourself.
This setup varies by provider. For example, TalkTalk Digital Voice is also a broadband-powered home-phone service, but equipment, availability and support arrangements are provider-specific.
What about care alarms, burglar alarms and other connected equipment?
This is where you should not assume compatibility simply because your telephone works. Government guidance says devices connected to the phone line — including telecare, alarms and fax machines — may need an adapter, an upgrade or their own battery and network backup.
BT says a healthcare alarm or pendant may not be supported on Digital Voice and the service provider should confirm compatibility before migration.
Monitored alarms that use the old phone line should be checked with the alarm company before the landline changes.
Lift phones, payment terminals, medical devices and other legacy equipment may have been designed around analogue signalling.
The 2026 PSTN Network Operator’s Charter strengthens protections for known telecare users: participating network operators commit not to migrate a known telecare customer without confirmation that a compatible and functioning solution is in place.
Even a perfectly compatible old handset may stop working if the broadband equipment loses power. Digital Voice depends on powered equipment in the home. Our separate guide explains whether a digital landline works during a power cut, including router power, ONTs, battery backup, 999 calls and care alarms.
What should I do with my existing phone?
Do not throw away a working handset just because your provider says your line is going digital. For most people, the old phone can continue to be useful once it is connected in the new way.
Check whether it is tone dialling, cordless DECT, amplified, rotary or another specialist type.
Include answer machines, fax, telecare, burglar alarms and anything else using a telephone socket.
Your provider should tell you what equipment, adapter or router setup applies to your service.
Make and receive a call, check ringing and caller ID, and separately test any critical alarm or assistive equipment.
If a handset has worked for years, start by testing it rather than replacing it. The switch is mainly about where the call travels, not forcing every household to buy a new telephone.
Most old phones can stay — the connection method is what changes
RNID and BT’s latest testing is reassuring for ordinary handsets, cordless phones and common assistive devices. A normal tone-dial phone will usually work through the router or adapter. The bigger checks are very old rotary phones, extension wiring, fax machines, telecare and anything else that relied on the old analogue line rather than just using it for a voice call.
Old phones and Digital Voice FAQs
Will my old landline phone work with Digital Voice?
Usually yes if it is a normal tone-dialling phone. BT says existing compatible handsets can be connected to the phone port on the Smart Hub or through a Digital Voice Adapter. Very old rotary or loop-disconnect phones are not supported in the normal way.
Will my cordless phone work after the Digital Voice switch?
Most cordless DECT phones should work. RNID and BT tested DECT phones successfully. The base station still needs power and normally connects to the router or a compatible adapter.
Will my answer machine or fax machine work with Digital Voice?
Answer machines generally worked in RNID and BT testing, although BT voicemail may answer first unless its settings are changed. Fax support is less certain: BT says fax can work but is not guaranteed, and RNID did not include fax machines in its device test.
Sources checked
RNID’s September 2026 testing with BT is the main evidence for handset and assistive-device compatibility. BT’s current Digital Voice help pages are used for connection, adapter, rotary-phone, extension, fax, telecare and power-cut guidance. Government sources provide the wider analogue-to-digital migration and telecare-protection context.
- RNID, 28 September 2026 — results from testing amplified phones, DECT phones, corded phones, textphones, alerting systems and answer machines with BT.
- BT — Existing handsets and fax machines — how existing phones connect and BT’s current position on fax compatibility.
- BT — Digital Voice Adapter — tone-dial phone support, adapter setup and the distinction for older bell-wire phones.
- BT — Moving to Digital Voice — switch-day setup, multiple phones and telecare or burglar-alarm checks.
- BT Digital Voice terms — confirms that loop-disconnect or old rotary dialling is not supported.
- BT — Digital Voice in a power cut — power dependency and support for customers without a reliable alternative.
- UK Government — Analogue to digital landline transition — guidance for telecare, alarms, fax and other connected devices.
- PSTN Network Operator’s Charter, March 2026 — commitments covering vulnerable and known telecare customers during migration.