- On the PSTN, the calling number was permanently tied to one installation address, so the emergency operator could see the registered location automatically.
- A VoIP line is not fixed to a single socket, so location relies on the address held by the provider rather than the physical copper pair.
- Ofcom's General Conditions require providers to make caller location information available to the emergency authority to the extent that it is technically feasible.
- The next generation 999, or ng999, programme is upgrading the UK emergency call platform to an IP-based system that improves how data accompanies a call.
- The legacy PSTN is being retired under Openreach's all-IP migration, scheduled to complete in 2027, after which digital voice location arrangements apply to most lines.
VoIP can pass your location to 999, but it relies on the address registered with your provider rather than a fixed copper line. Ofcom requires providers to share location where technically feasible, and ng999 is improving how this works.
Last reviewed: June 2026
How the old copper network knew where you were
The strength of the analogue 999 call was something most people never thought about. When a copper line was installed, the telephone number was bound to that physical address in the network's records. Because the copper pair ran from the exchange to one specific socket, there was no ambiguity about where the caller sat. The moment a 999 call connected, the operator could pull up the registered address associated with that line. The location came for free, built into the architecture of the network, and it did not depend on the caller being able to speak or knowing exactly where they were.
This mattered most in exactly the situations where a 999 call is hardest to make. A caller having a stroke, choking, hiding from an intruder or overcome by smoke may be unable to give an address, and a young child reaching for the phone may not know one. On the copper network the address was delivered by the line itself, independent of anything the caller said, which is why the analogue system was so dependable for vulnerable callers. That dependability was a property of the wiring rather than a feature anyone had to maintain, and it is the part that is most valuable to preserve as the network changes.
That tight link between number, line and address is the feature that VoIP cannot inherit automatically. The copper pair was, in effect, a fixed pointer to a place. Digital voice removes the fixed pointer, which is why location handling has had to be redesigned rather than simply carried across.
Why VoIP location is harder
VoIP carries the call as data over the broadband connection, and data is portable in a way that a copper pair is not. In principle, a VoIP adapter or app could be plugged in or signed in from anywhere with an internet connection, so the network can no longer assume that the number lives at one fixed socket. The provider therefore has to rely on the address that the customer registered, usually the installation address, to tell the emergency services where to send help. If that address is wrong or out of date, the location passed on will be wrong too.
There is a further complication. Internet routing does not map neatly onto geography, and the IP address a device uses is not a reliable indicator of a street address. A connection can be routed through equipment some distance away, and an app on a mobile network can move between cells, so deriving a precise doorstep from the internet path alone is not dependable. This is why providers do not try to derive your location from your internet connection alone; they use the registered service address as the authoritative record. For fixed home VoIP, that address is normally accurate because the line is installed and used in one place. The risk arises mainly when equipment is moved without telling the provider, which is exactly the scenario the rules and the ng999 programme are designed to manage.
PSTN versus VoIP emergency location compared
The contrast between the two approaches is best seen side by side. The table below sets out how location is determined on each, and what the customer needs to do to keep it accurate.
| Aspect | PSTN (analogue) | VoIP (digital) |
|---|---|---|
| Source of location | Fixed copper line tied to an address | Address registered with the provider |
| Portability of line | Tied to one physical socket | Can in principle be used elsewhere |
| Accuracy risk | Very low, address is structural | Depends on registered address being current |
| Power resilience | Exchange-powered, works in a power cut | Needs mains power and broadband |
| Future platform | Legacy, being retired | Supported by ng999 IP platform |
The single most useful takeaway from this comparison is that VoIP location accuracy is in the customer's hands to a degree the old network never required. Keeping the registered address correct is the practical equivalent of the structural certainty the copper pair used to provide.
How providers are addressing it and what ng999 is
The UK is modernising the emergency call system itself. The next generation 999 programme, known as ng999, replaces the older call-handling platform with an IP-based system. The aim is to make the emergency call infrastructure resilient and flexible enough to handle calls from modern networks, including VoIP, and to improve how supporting information such as location accompanies a call. As more of the country moves to digital voice, ng999 provides the platform on which location and other data can be delivered to call handlers in a consistent way.
It helps to separate the two layers involved. The call-handling platform is the system that receives and routes 999 calls and presents information to the operator, and ng999 modernises that layer so it can work natively with internet-based networks rather than the legacy analogue infrastructure it grew up alongside. The other layer is the provider's own record of where the customer is, which is the source of the address in the first place. Both have to work together: an upgraded platform cannot improve on an address the provider holds incorrectly, and an accurate address is most useful when the platform can carry it cleanly to the operator. ng999 addresses the platform layer while Ofcom's General Conditions place the duty on providers to make location available, so the two combine to replace what copper did automatically.
Alongside the platform upgrade, providers manage location through their own records and processes. They hold the registered installation address, they ask customers to confirm or update it, and they pass it on when a 999 call is made. Some services also prompt customers to confirm their location during setup or after a house move. The combination of an accurate provider record and the ng999 platform is how the system aims to replace the automatic location that the copper network gave for free.
Telecare alarms and other connected devices
Location is not only a concern for the phone itself. Many households rely on a telecare or personal alarm that dials a monitoring centre when a pendant button is pressed, and on the analogue network those alarms used the same copper line and the same structural certainty about where the caller was. On a digital line a telecare alarm depends on the registered address and on the device having been confirmed to work over the new connection, so a move or a change of equipment without telling the alarm provider can leave the monitoring centre dispatching help to the wrong place. The alarm provider, not only the phone provider, needs the correct address on record.
The same logic extends to any device that makes a call on the customer's behalf without a person speaking, such as a monitored intruder alarm or a careline unit. Because these systems cannot describe their location verbally, they depend entirely on the address held against the service, which makes keeping that record current even more important than it is for an ordinary handset. Households that rely on such a device should confirm with the relevant provider that it has been tested on the digital line, that the correct address is registered, and that there is a plan for how the device behaves in a power cut, since like the phone it will need mains power and broadband to work.
What this means for you
For a typical household with a fixed home VoIP line, location for 999 will normally be accurate because the line is installed and used at the registered address. The most important thing a customer can do is keep that address up to date with the provider, particularly after moving home or relocating the equipment within a property. If the registered address is wrong, the emergency services may be sent to the wrong place, so a quick confirmation call to the provider after any change is worthwhile.
It is also worth remembering that location handling is only part of emergency resilience. A VoIP 999 call still depends on working broadband and mains power, so a charged mobile remains the simplest fallback in an outage. Households who rely on the landline because of age, disability or a telecare alarm should ask their provider about power-resilience support as well as confirming their location record. Treating location and power as two linked checks gives the most complete protection.
Frequently Asked Questions
Does VoIP send my location to 999?
Yes, providers must make caller location available to the emergency authority to the extent that is technically feasible. On a VoIP line this relies on the address registered with the provider rather than a fixed copper pair. Keeping that registered address accurate is what ensures the right location reaches the call handler, particularly if a caller cannot speak or describe where they are.
What is ng999?
The next generation 999, or ng999, is the programme upgrading the UK emergency call platform to an IP-based system. It is designed to handle calls from modern networks, including VoIP, and to improve how supporting information such as location is delivered to emergency call handlers as the country moves to digital voice. It modernises the call-handling layer that receives and routes 999 calls.
How does the emergency services know where I am if I call on VoIP?
The provider passes on the address it holds for your line, normally the installation address, to the authority handling the call. Because a digital line is not tied to one physical socket the way copper was, this registered record is the authoritative source rather than the internet connection. For a fixed home line used at the registered address, that location is normally accurate.
What if I move my VoIP phone to a different address?
If you move the equipment or move home, the location passed to 999 may be wrong until you update your registered address with the provider. The line carries the address on record, not the place where the device is physically plugged in. Contacting the provider to confirm the new address after any move keeps the emergency location accurate, and the same applies to any telecare or alarm device.
What are providers required to do about VoIP location for 999?
Under Ofcom's General Conditions, providers must make caller location information available to the emergency authority to the extent that it is technically feasible. In practice that means holding an accurate registered address, asking customers to keep it current, and delivering it when a 999 call is made, supported by the ng999 platform that carries the data to the operator.
