Power on the line

Who ensures you can call 999 in a power cut?

This blog does not have all the answers, it has a lot of questions, opinion, and some history. I am trying to address the issue and explain some of the technical, financial, and regulatory challenges. It is not simple, and some will undoubtably have a different opinion. I hope it helps address the very understandable knee jerk responses though.

I also have personal views on 999 service moving to the 21st century, but this blog covers just power for 999 calls.

A bit of history

Telephones have been around well over 100 years now. Surprisingly the basic working of the old fashioned analogue phone still works today, but that is changing.

They way an analogue phone works happens to need a small amount of power. There needs to be a voltage (no power really) to detect you lift the receiver. There needs to be enough power to allow the microphone and earpiece to work. There needs to be a bit more power to make a bell ring. This was done using batteries at the telephone exchange.

This meant a telephone would work without the home having power. Indeed, mains power was less common and less reliable over a century ago when phones started. It is also worth remembering that consumer electronics did not exist either - these days we see DC USB power on wall sockets and are used to a small switch mode power supply working some electronic gadget - the idea of a telephone handset being powered from you home is not daft. But a century ago the very power supply itself would be complicated, to say the least, and the phone handset had no electronics anyway - it would not make any sense for a telephone handset to be power from your home mains electricity. So they were line powered, simple as that.

The telephone handset was also part of the service, even wired in, for a very long time.

Catch up to today

Today, analogue telephone lines do the same. Yes we have DTMF now, and the handset itself has electronics that do that, but a simple handset is powered by the line still. Of course we have also moved to the telephone being the customer's responsibility and not part of the service itself, something you can choose, and plug in.

It is an issue for the telcos as the electronics in a handset could expect more power than the original telephone lines were every designed to deliver and there are current limits defined as a result.

But also we have a lot more complex telephones now, even simple cordless phones, DECT base stations. phone with answering machine, PABX, and so on. These work using local mains power, and in some cases DO NOT work when no local mains power. In a lot of cases there are special work arounds - a phone system in an office will typically have at least one old school phone, and maybe a relay that switches that directly to the line when power fails. But not all consumer equipment has any means to work in a power failure.

But also, mains power is way more reliable in almost all places.

However, if you have a simple old school telephone handset somewhere in the house, you can still use it during a power cut - yay!

20th Century

For a long time it was expected that ISDN was the future. Indeed, in some countries it really did take off, and a basic ISDN2 telephone could plug in to a socket and work. My understanding is that ISDN2 was design to power a basic ISDN telephone.

I am not sure if BT did power ISDN2 sockets - I have a feeling they did not. They did a consumer ISDN2 (Home Highway) which did have an analogue phone fallback, which was good. But for anyone using ISDN2, an actual ISDN2 handset was unheard of - people used and ISDN2 card in a computer (mainly for data) or a small ISDN2 PABX which needed power to work.

ISDN30 is a large scale service, and that definitely did not power a handset. It was often using fibre. It did not have power fail working, even though 999 should work just as much for such cases as a home phone line.

Somehow BT were legally able to provide a proper telephone service on a line in such cases with no power fail backup! (Do correct me if I have that wrong).

21st Century

The problem is that times are changing, the old school telephone service (landlines) are going away. These days telephony is an over the top service, working over IP, VoIP, that is Internet Protocol. This changes things.

So how does this work in a power cut and who is responsible for it?

Broadband/Internet

A broadband/internet service never had any requirement to be 24/7 100% reliable, or to work in a power failure. OFCOM are pushing more and more for this, and even talking of power failure requirements (for at risk customers, at least). This is a change, and has a cost.

The internet itself is a large interconnected network - an ISP cannot guarantee that even Google works 24/7, that is down to Google, and even they had an outage the other day. An ISP cannot guarantee they have connectivity to some VoIP telephone service provider 100% of the time, as a lot of that connectivity is outside the ISPs control, as is the operation of the VoIP provider themselves. Yes, an ISP may also be a VoIP provider, but there is not reason to make more onerous obligations in such a case, especially as such a company could simply split its operations in two if that was the case, so assume they are separate.

The elephant in the room here is actually where and what a broadband/internet service is - it is provided at the Network Termination Point. For DSL this is the master socket. It is a clear demarkation for where service is provider.

If OFCOM insist that an ISP has to have a broadband service that works during a power failure (even if only for an hour), that is the point at which it has to work. That is no different to the landline provider providing service at the master socket.

The problem is, unlike a landline, having a service working at a master socket is not a lot of help to a consumer in a power cut. Unlike a landline telephone service, broadband service never provided power (for a router). It provides connectivity - the ability to DSL sync on the line using a modem. You need a modem, and that needs power.

Interestingly, BT are talking of battery backup for optical network termination points (ONTs), where the network termination point is an Ethernet socket. That could be useful to a customer if they have a laptop with an Ethernet port and a PPPoE stack. That would allow them internet access in a power cut. But that is an edge case. In almost all cases the consumer has a modem/router/switch/access point, and they have to power that to make it work. Just as they would have to power a DECT base station if they had one plugged in to a landline master socket.

From a regulatory point of view the whole concept of a network termination point is important, it defines where the service is provide and who is responsible each side. The ISP is simply not responsible for what is plugged in.

From a technical point of view the ISP could not sensibly power arbitrary customer equipment. Here, for my laptop to work, I have a router, and modem, and large PoE switch, and 6 access points. Powering all of those for an hour is a big undersaking, but not doing that means I don't have internet at all. I don't have a system to fall back to just a modem and one access point, but powering even one AP is a lot.

Should companies making and selling network routers, switches, and access points, have to ensure battery back up, just because they could be used to carry VoIP traffic for a 999 calls?

So yes, I suspect a service still working at the network termination point, and hence powered ONT, might happen. It happens for DSL lines, we think (BT have batteries in street cabinets, but not sure if all, or for how long). But it will be not help for 999 calls.

VoIP provider

The other side of the coin is a telephone service provider using VoIP.

The very nature of the service is that it is oIP, i.e. over IP. It depends on working internet access.

Does it make sense to expect the VoIP provider to somehow make it work when no internet access, well no, it does not.

Does it make sense for the VoIP provider to provide battery backup? Well, for what? If the provider rented a SIP handset, maybe they could power that for you, but that does not help in a power cut if nobody is powering your modem, router, and network switch, all of which are very much out of the scope of the VoIP provider. And if they are not renting a SIP handset, or providing as part of the service, even that handset is out of scope.

I VoIP provider should ensure their equipment has power backup and redundancy to allow 999 calls, but that is actually pretty easy in a data centre. Data centres have lots of power backup and redundancies.

The key issue here is that making the broadband work at home is down to a lot of equipment for which the consumer is totally responsible, and not the broadband provider, and not the VoIP provider.

Should companies making/selling SIP handset have to ensure battery backup? And would it help? Maybe if modem and switch manufactures had to do the same. But none of that sounds sensible.

Landline replacement

There is a middle ground here, a landline replacement service. This is something we see, and likely to be something BT has to do as the incumbent operator with a Universal Service Obligation.

Being a replacement it IS REASONABLE for the customer to expect it to work like the service it replaces. This means a provide providing not just internet access to a network termination point, but modem and router with an old school analogue telephone socket. The termination point for that overall service is the analogue phone socket on the router, and so it is reasonable to expect that to work in a power cut, with an old school analogue phone. So likely that will have battery backup as an option.

So, at least for now, due to jet more legacy it is likely BT will still provide this, at least for at risk customers.

Should someone else do this anyway

The big issue at hand is power cut. Would it not simply be sensible to regulate that power companies have to do something.

They already have a priority service register and already roll out generators to vulnerable users (e.g. those with powered medical equipment at home). I'm on the register as I have insulin in the fridge, which was one of the criteria - I also (now) have Tesla batteries so won't need a generator for even a very long power cut.

Having to provide a small USP enough to cover a broadband modem, and router, and SIP ATA to work a handset, is not a big step, and not a huge cost if only for at risk customers.

It makes a lot more sense that insisting telcos provide power. Just like it makes sense that power companies are not expected to provide telephony.

Maybe this is the real way forward here?