back to article BT pushes ahead with plans to switch off telephone network

BT is forging ahead with plans to shut its traditional telephone network in Britain, with the intention of shifting all customers over to IP telephony services by 2025. The closure of the public switched telephone network (PSTN) is part of plans by BT toward internet-based voice calls via a fibre network. As such it will be …

Page:

    1. anthonyhegedus Silver badge

      Most people have cordless phones. How do they work in a blackout? A good proportion of people don't use a landline phone. How do they work in a blackout?

      The answer is that this would have seemed like a problem back 20 years ago - remember when rabbit cordless phones came out? The base station had a 9V battery backup. That was the first digital cordless phone on sale in the UK, and people were probably genuinely worried about such things. These days... I think not so many people care so much.

      1. handleoclast Silver badge

        @anthonyhegedus

        Most people have cordless phones. How do they work in a blackout?

        The handsets continue to work just fine, because they have rechargeable batteries in them,

        The base stations, however, are a different matter. Most of them do not have rechargeable batteries in them.

        The solution is to always have at least one standard phone. If you're sensible, you put phone sockets and a standard phone anywhere you have a handset charging station, because you never know where you'll be in an emergency (like a fire that incidentally happens to burn through the electrics and trip the breaker). Standard phones are cheap enough. You probably have the sockets already from back before you bought the cordless phones.

        My view is that the reason you have a cordless phone is so you can wander from room to room as you talk (go to the kitchen for a snack, go back to the computer, have a piss, etc.) and you have an ordinary phone for when you've lost the cordless or in an emergency. YMMV.

        1. Bond007

          Re: @anthonyhegedus

          "The handsets continue to work just fine, because they have rechargeable batteries in them,

          The base stations, however, are a different matter. Most of them do not have rechargeable batteries in them."

          Isn't that a bit of a contradiction? If the base station either doesn't use or has batteries which aren't rechargeable, then the handsets won't continue to "work just fine" if the batts run out, will they?!

          1. handleoclast Silver badge

            Re: @anthonyhegedus

            Isn't that a bit of a contradiction? If the base station either doesn't use or has batteries which aren't rechargeable, then the handsets won't continue to "work just fine" if the batts run out, will they?!

            No contradiction at all.

            The handsets work fine. Their display works. Their keypad works. Their RF section works. They work just fine. Without a working base station they're unusable (except as paperweights) but they do work.

            I've upvoted you anyway for being a pedant. :)

            1. Bond007

              Re: @anthonyhegedus

              Apologies Anthony for being a 'pedant', maybe I've missed part of what you said, but what exactly IS the point of mentioning that the handset(s) work, when if the base stations DON'T, that then renders them useless, regardless of whether the display/keypad/RF etc works eh???!!!

              If you have multiple base(s) in your house (which I'm guessing YOU might?), then I think my point ultimately STILL applies!

              Can you tell me what I've missed please?

              FWIW I have a wireless phone in MY house too, but only one base (whether it uses batteries or not, I'm not sure)

              1. Phil O'Sophical Silver badge
                Coat

                Re: @anthonyhegedus

                when if the base stations DON'T, that then renders them useless, regardless of whether the display/keypad/RF etc works eh???!!!

                Well, you'd be able to look up the phone number that you need to dial on the old wired phone...

                1. Bond007

                  Re: @anthonyhegedus

                  Fair point! BUT, aside from being able to use the handsets as a digital phone book, they ARE useless in all other regards, are they not?!

                  Also (sorry for being a 'pedant' again) ; , but the original question was:

                  "Most people have cordless phones. How do they work in a blackout?", which was only really answered with the batteries line... so they'll only work up to a point!

                  Which is why I made the point about the issue with batteries, end of! ;)

      2. Doctor Syntax Silver badge

        "Most people have cordless phones. How do they work in a blackout?"

        I have cordless. I wouldn't expect them to work in a power cut. That's why I also have an ordinary phone plugged into another socket.

      3. CrazyOldCatMan Silver badge

        Most people have cordless phones. How do they work in a blackout?

        Which is exactly why I have an old push-button phone in the cupboard under where the cordless phone sits..

    2. sanmigueelbeer Silver badge

      I think the home analogue phone will not be replaced. At the exchange shift will be done to logically connect the analogue "lines" to VoIP.

      I am not sure if I take this seriously because a lot of phone providers worldwide have been shifting from mechanical (crash and bang) to IP for so many years. I mean, one may have an analogue phone at home but at the exchange it is being transferred at IP level already.

      1. Paul Shirley

        sanmigueelbeer" I think the home analogue phone will not be replaced. At the exchange shift will be done to logically connect the analogue "lines" to VoIP."

        That's how the system has worked since system x was introduced decades ago, over BTs network not the public internet. The announcement can only mean VoIP from the premises or cabinet. A move to purely fibre requires something that looks like VoIP so they might as well just use the existing standards.

        Broadband modems sometimes have phone support built in already, virgin have it disabled in their Superhub, haven't checked BT recently but they used to have some sort of support in their modems. The hardware for adapters is cheap enough that a backup battery will be most of the cost!

    3. streaky Silver badge

      The hell is a blackout?

      On a more serious note of the 5 people that still actually use a landline 4 of them use wireless phones that take power from the mains anyway. The odds of that one person needing to call 999 is almost zero.

      1. Anonymous Coward
        Anonymous Coward

        The odds of that one person needing to call 999 is almost zero.

        Milion to one, you mean?!

        This is the fallacy I see so often in disaster planning, the assumption that something is so unlikely it isn't worth worrying about, completely forgetting that it is precisely in that unlikely situation that you'll need it the most.

        1. Sarah Balfour

          But everyone knows million-to-one chances crop up 9 times out of 10.

      2. David Nash Silver badge
        Headmaster

        "The hell is a blackout?"

        What happened to "What"?

    4. Anonymous Coward
      Anonymous Coward

      DR/BC

      In the event of a power outage, the equipment at the exchange will have a backup to cover disaster recovery situations to allow 999 calls.

      It should be part of the BCDR plan for the exchange. Hopefully being frequently tested to ensure it works.

  1. Hoppy

    Yeah right

    They cant even get me above 352kbs let along voip so good luck with that.

    I was going to entitle this T*ssers but decided not to :)

    1. Paul

      Re: Yeah right

      VOIP doesn't need much bandwidth at all, a few tens of kilobits/second if that.

      what it does need is power. old fashioned analogue phones are powered by the phone line, you don't get that with an optical fibre, and so a SIP ATA needs a mains adapter and battery backup.

      how many people have cordless phones at home where the base station has no battery backup? I think probably 99% of cordless phone base stations have no battery.

      1. David Webb

        Re: Yeah right

        My Fibre ONT has a battery backup which allows a Fibre phone to work during a power cut. Not that my provider offers the service, but the guy from OR put the battery in so when the battery broke down I got OR out to come and replace it, even if I don't need it, you drill the holes you're going to fix it if it messes up.

      2. quxinot

        Re: Yeah right

        >VOIP doesn't need much bandwidth at all, a few tens of kilobits/second if that.<

        Depends on if you want it to be understandable and of decent quality or not. I'm sure that they'll immediately turn down the bitrate into single digits so that all conversations are along the lines of talking to Charlie Brown's teachers.

        https://www.youtube.com/watch?v=ss2hULhXf04

        I know VOIP is better than it was some years ago, but it certainly seems that overall phone call quality has gone dramatically down over the years.

        1. Christian Berger Silver badge

          Re: Yeah right

          "I know VOIP is better than it was some years ago, but it certainly seems that overall phone call quality has gone dramatically down over the years."

          Well that depends on many factors. There are providers and PBXes insisting on the god awful G.729 for example, while any decent provider will use G.711 which is just as good as ISDN (but with a longer delay), good providers will support G.722 which does much better quality at the same bitrate. Another problem are really bad ATAs. Quality doesn't seem to correlate with price. The best ones (I've seen) for home uses are the "Fritz!Box" series from AVM, which you can get refurbished for about 70 Euros, but cost around 150-200 Euros for the top of the line model... which includes an internal ISDN port, a DECT base station, as well as a V/ADSL modem. Software support usually is several years for feature updates, and longer for security updates.

      3. Anonymous Coward
        Anonymous Coward

        Re: VOIP doesn't need much bandwidth

        "VOIP doesn't need much bandwidth at all, a few tens of kilobits/second if that."

        Depends where you look/measure (and has done for years, and will continue to do so).

        At the end user end of the setup, e.g. most homes, offices, etc, the IP protocol overhead massively exceeds the bandwidth of the conversation itself, if there's only one or two phone calls on the wires. But you try getting more than one or two VoIP calls over a couple of Mbit of bandwidth and you're heading for trouble, bigtime.

        And don't forget that for intelligible voice conversations, latency can be quite important too. Latency often doesn't improve as bandwidth increases; often quite the reverse.

        "I think probably 99% of cordless phone base stations have no battery."

        Maybe so, but that's currently fixable with a couple of boatloads of line-powered phones. Lose line power, and more importantly switch the backbone to cheap IP kit (they're not moving to IP to improve service, are they?), and then how do you fix the "wide area power loss" problem.

        Ask someone who was in Lancaster when it mattered.

        1. Mr Sceptical
          Facepalm

          Surely they're offering full spectrum audio now...?

          BT have totally failed to say they'd be able to offer much better audio quality on a decent VOIP line rather than the 'select' frequency range we've suffered until now. This is the best opportunity to upgrade call quality since phone lines became commonplace last century.

          Anyone who's compared the audio quality of a Skype* call to the fixed or mobile standard realises it's comparing two tin cans & string to studio monitors.

          Plus, if all the VOIP handsets can't handle that quality audio then they've an excellent opportunity to partner with ones who can.

          Anyone would think the commercial opportunities here have been deliberately overlooked just to reduce their ongoing PSTN costs - very short-sighted!

          * caveat: over a decent internet connection.

      4. TechDrone

        Re: Yeah right

        650VA UPS under the stairs runs a house server, 14 port hub, VDSL router and Wifi bridge and phone base station or 35 minutes no problem. Most electrical works of late have taken 45 minutes...

        I've no idea who long it will run the phone base station by itself as I can't be bothered to sit in the dark long enough to find out. I suspect more power is lost in the UPS overhead than is used by the phone.

        I did try to get ethernet out to the garage for a second house server for redundancy but the missus decided I was taking things a little too far.

    2. Peter Gathercole Silver badge

      Re: Yeah right @Hoppy

      If I remember correctly, ISDN specified a 144Kb/s link, which could carry a 2 voice calls, each using 64Kb/s, and a 16Kb/s signaling channel.

      Also IIRC from my POTS training, analog phone lines used to have a filter at 8KHz, which was regarded as plenty high enough to carry voice communications.

      1. Christian Berger Silver badge

        Re: Yeah right @Hoppy

        "If I remember correctly, ISDN specified a 144Kb/s link, which could carry a 2 voice calls, each using 64Kb/s, and a 16Kb/s signaling channel."

        That's correct, though those 2 64k channels could carry everything, even non-voice. It's signalled via the "bearer-capability".

        "Also IIRC from my POTS training, analog phone lines used to have a filter at 8KHz, which was regarded as plenty high enough to carry voice communications."

        Well there were early very long lines which used indutances on the lines which acted as a low pass filter, but extended the reach. I don't know exactly where that filter was.

        However the actual limit was when carrier-wave systems were introduced shortly before WWII. Those stacked voice channels in frequency so a single coaxial cable could carry dozends of voice channels. So obviously you had steep filters to only give you a passband of 300-3400 Hz so they could stack more channels. (in fact there are reports about the stacking being changed during the day, so at night you actually got wider channels) Back in the days however you were likely to even get less if you had a worn out microphone capsule.

        As for digital telephone networks they decided to use a sampling rate of 8000Hz as this allowed for affordable analog filters on both sides and was well withing the technical capabilities of the 1960s. The codec they used was G.711 which could be implemented fairly easily as it could be done by having some analogue circuity and an 8-Bit A/D converter.

        ISDN actually had a special bearer capability for G.722 encoded audio which allows for frequencies of up to about 7.2 kHz to be transmitted over a single 64k channel. This caused quite some hype at radio stations, but ultimately fell into obscurity.

  2. Trollslayer Silver badge

    Mobile as the emergency option?

    It sounds reasonable.

    Plus if the cable duct is damaged beyond use POTS wouldn't work.

    1. John Robson Silver badge

      Re: Mobile as the emergency option?

      Not really - you don't get location information from mobile.

      And in the event of a power failure your plain phone will work just fine - your fancy VoIP phone, with it's reliance on a separate route, access point, switch...??? will not.

      1. ARGO

        Re: Mobile as the emergency option?

        >you don't get location information from mobile

        Networks have always provided an area ID based on the cell the phone is connected to.

        But if you have a smartphone there's a good chance it supports "Advanced Mobile Location" - the phone sends a 999 SMS with location data taken from any location info the phone itself has available.

        1. John Robson Silver badge

          Re: Mobile as the emergency option?

          >you don't get location information from mobile

          Networks have always provided an area ID based on the cell the phone is connected to.

          Area ID isn't a house though.

          and given the response from the emergency services when I have phoned them from my mobile - they get absolutely no location data at all...

      2. Mjones

        Re: Mobile as the emergency option?

        You do get location from a mobile - if it is using AML and requires certain phone OS's (need to have IOS 11.3, Android 9) at the moment. However, the control rooms also get a triangulation data from the mobile network masts (cells) your phone is registered on - this is accurate to 100m ellipse in built up areas but less in rural - depends on the density of mobile cells.

        From the POTS perspective the control room gets the subscribers address details (via EISEC data base lookup) - which comes in very handy for premises aware / risk based mobilisation i.e. nice for them to know in a fire emergency that you live next door to the local petrol station, or live in a flat above a welders, are an old folks home etc. Can't quite see how that works in the future (unless we all have a premises specific IPv6 address and BT re-create the EISEC data base from it).

        1. Benny

          Re: Mobile as the emergency option?

          We provide VoIP and have a direct link to BT to pass calls, and we have to provide BT with address details that match with the CLI of the line.

          We don't let customers set their own CLI, (and even if withheld to the other party, BT still see the real CLI) so emergency calls still get the correct address data.

          1. Anonymous Coward
            Anonymous Coward

            "so emergency calls still get the correct address data"

            Until the customer moves house and forgets to update their account details.

        2. John Robson Silver badge

          Re: Mobile as the emergency option?

          "You do get location from a mobile - if it is using AML and requires certain phone OS's (need to have IOS 11.3, Android 9) at the moment. However, the control rooms also get a triangulation data from the mobile network masts (cells) your phone is registered on - this is accurate to 100m ellipse in built up areas but less in rural - depends on the density of mobile cells."

          I've never had any indication from any emergency services operator that they have even the foggiest idea where I am from their control room.

          And given that control rooms are not generally all that 'local' the operator still often doesn't have a clue until I go out to motorway* junctions and then navigate them from there...

          I take the 'emergency services get your location with a massive handful of salt, at least in the UK...

          (Whether M class, or just de facto motorway)

          1. Roland6 Silver badge

            Re: Mobile as the emergency option?

            >I've never had any indication from any emergency services operator that they have even the foggiest idea where I am from their control room.

            I've had a mobile emergency call connected to the wrong geographic control room, fortunately, it was only a car fire and all the people had safely got out...

      3. Christian Berger Silver badge

        Re: Mobile as the emergency option?

        "Not really - you don't get location information from mobile."

        That really depends on many factors. The interface towards the emergency services in Germany has ways to transmit either an address or a set of geometrical figures indicating the location. In the US, for example, virtually all phones have a way to capture a short burst of GPS data which then will be sent to the base stations in order to get a location fix for the phone which will then be transmitted.

      4. Spanners Silver badge
        Happy

        Re: Mobile as the emergency option?

        Not really - you don't get location information from mobile.

        When I called 999 a few years ago, I think they asked me to confirm my location, not tell them it. I had to correct it because I was not by the fire. I was looking across an industrial estate at a burning skip!

    2. Alister Silver badge

      Re: Mobile as the emergency option?

      It sounds reasonable.

      It doesn't sound so reasonable when you consider mobile network coverage is only at about 85% in the UK. There's still a lot of places without a signal.

      1. This post has been deleted by its author

        1. Pete4000uk

          Re: Mobile as the emergency option?

          What they should do, is put a large box on every other street corner which contains a telephone with its own long term UPS which people can use in an emergency. We can paint it red to make it stand out and put CCTV in so anyone vandalising them get a swift caution.

          1. dnicholas Bronze badge

            Re: Mobile as the emergency option?

            Does is also double as a urinal for late night trips home?

            1. TRT Silver badge

              Re: Mobile as the emergency option?

              It does have an IP service, yes.

      2. Doctor Syntax Silver badge

        Re: Mobile as the emergency option?

        "There's still a lot of places without a signal."

        Or a signal but not on your network.

        1. Phil O'Sophical Silver badge

          Re: Mobile as the emergency option?

          Or a signal but not on your network.

          You can still make emergency calls in that case, it's required by law. 112/999 will work.

    3. Gideon 1

      Re: Mobile as the emergency option?

      There won't be POTS, instead fibre to the premises with a battery backed Optical Termination Unit.

      1. TRT Silver badge

        Re: Mobile as the emergency option?

        So... around 5,600 local telephone exchanges in the UK, each, let's be generous, having around 100 cabinets, so around 560,000 geographically dispersed battery backed up units... unless they plan to run new PSU cables out to the cabinets from a central power source at each exchange... so what's the problem with POTS again?

      2. Doctor Syntax Silver badge

        Re: Mobile as the emergency option?

        "There won't be POTS, instead fibre to the premises with a battery backed Optical Termination Unit."

        You really think there'll be a 100% FTTP roll-out in that time period? And if there was how do you think it'll be paid for without dumping costs on people who didn't even ask for it and see no benefit?

        1. Anonymous Coward
          Anonymous Coward

          Re: Mobile as the emergency option?

          "You really think there'll be a 100% FTTP roll-out in that time period? And if there was how do you think it'll be paid for without dumping costs on people who didn't even ask for it and see no benefit?"

          The simple answer is "tough" - technology has moved on and it shouldn't be held back because a few people refuse to pay a little bit more. Nor should Openreach be expected to maintain an aging, rotting copper network to satisfy a few holdouts. Once FTTH reaches 100% coverage in an area, they should be allowed to start forcibly moving people off - maybe sweeten it with grandfathered pricing.

          The more complex answer is "they actually might not have to pay more" - none of us know Openreach's costs but other large telcos have reported that FTTH networks are far cheaper to operate, maintain and repair - especially once you can abandon the copper and shift everyone over. FTTH can just as easily provide a low bandwidth cheap skate service while the person next door gets their symmetrical gigabit service.

  3. Anonymous Coward
    Anonymous Coward

    Digital Fibre Future

    "..... and represents a move from an analogue to a digital, fibre led future."

    And there was me thinking the PSTN had been mostly converted to digital and fibre based from around 1985-ish.

    Silly me. Or is this more marketing fluff from clueless and witless marketing droids?

    1. This post has been deleted by its author

Page:

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Biting the hand that feeds IT © 1998–2019