UKC

BT have just delivered us a new ADSL router with a phone socket, as we move to “Digital Voice”, which runs over the internet connection.  Our analogue phone feed will soon be disconnected.  I’d completely missed the news that “plain old telephone system” was being dismantled until we got a letter through the post about the coming change,

Given our experience of the ADSL and cellular networks folding within 12 hours during the powercuts following each of storm’s Arwen and Eowyn it’s hard to see how this doesn’t represent a major degradation in 999 capability.  

Still, I look forwards to seeing the cost savings in my bill of reducing the number of systems BT runs…  Probably time to ditch the landline phone for good.

In reply to wintertree:

https://www.ofcom.org.uk/phones-and-broadband/landline-phones/future-of-lan...

BT have to give you a back up battery [with obvious issues] or even a mobile phone.

Can't help with the reduction in price question, though.....

In reply to wintertree:

Can you stand on high ground and use semaphore (or Aldiss lamp after sunset)?

In reply to wintertree:

Not VDSL...?

In reply to wintertree:

Yep, most people's DSL comes from Street cabinets which may or may not have battery backup only.  The good news is that when you go fibre you're more likely to be fed from an exchange with battery and generator backup.

In reply to wintertree:

Your thread title was just one letter away from being something thrilling.

In reply to captain paranoia:

You’re right, I haven’t kept up on my acronyms.

In reply to Toerag:

Yes, the FTTC gear in our local cabinet lasts less than a day on its local batteries.

I had - for no particular reason - assumed it would be trunked from the exchange to the cabinet and broken out there with some active gear.  Is it literally one fibre per premises back to the exchange?  That would be cool.  Although we only got FTTC a few years back so I’m not holding out hope.

I realised rather slowly that my mobile does have satellite based emergency SMS which should still work in a prolonged power cut; I had been looking forwards to full cellular service from Starlink but the chances of me paying for that have recently tanked.

In reply to wintertree:

I really hope BT have improved their service vastly, for your sake. My parents' had BT and, whilst I looked after that house for six years, I continued to use BT for both landline and internet. Every year or so BT would provide a new router, but there were endless problems and frequent service cut-outs. Their continual overcharging and terrible accounting drove me nuts. When I moved houses four years ago, I moved to another service provider and have had  none of those problems.

In reply to wintertree:

It's fibre all the way back to the exchange with passive optical splitters in the distribution network - normally in manholes.  https://en.wikipedia.org/wiki/GPON 

In reply to Toerag:

Ours is at the top of the telephone pole at the bottom of our garden!  Actually, the pole is at the bottom of the garden of the house that backs on to ours, but for some reason Openreach seem to prefer coming through our property to access it.  Which I don't actually have a problem with since the Openreach techs round here are generally a friendly bunch and happy to have a chat about what they're doing.  (We've been having problems with our copper-based ADSL recently and the Openreach tech who came round to look at it spent a good couple of hours replacing a knackered bit of cable at the back of the house, and installing two new phone sockets inside the house, despite the fact that we're getting our full fibre connection in a couple of weeks time.  I think that's what's called keeping the customer happy.)

As for the demise of POTS, I have already signed up with Andrews & Arnold for VoIP service.  We're sticking with our current ISP which doesn't offer "Digital Voice", and from what I've heard about some of the issues that BT's offering seems to be causing for some users, I feel happier taking responsibility for it myself.

I already have a UPS for the NAS which the main router also runs off, and there's capacity on it to support Openreach's Optical Network Terminal (ONT) and Andrews and Arnold's Analogue Telephone Adaptor (ATA) when the time comes.  The NAS can only provide an hour or so's cover but that should be enough for the short blackouts we do suffer here from time to time.  If we do have a longer outage then, living in a suburban area, we're in a better position to resort to pre-industrial communication technologies than might be the case for folks in more isolated locations.

I've verified that our current intruder alarm can make outgoing calls using the VoIP solution, so I should still get alerted on my mobile if there's a break-in while we're out.  The one thing I haven't managed to get working so far is acknowledging the alarm using DTMF from the mobile.  For some reason the DTMF doesn't seem to make it through the VoIP.  I believe it's just a configuration issue with the ATA that should be sortable given time, but for various reasons time is one thing that is in short supply at the moment

In reply to Toerag:

Time division multiplexing with passive splitters?  So the data for any given household on a shared fibre is sent to every household on that fibre, but the terminals promise to only listen to what they’re supposed to?

The high upload speed would be amazing.  

The other thing that dawned on me about digital voice is that any house that still uses multiple wired telephones is screwed as the analogue signal is recreated at the router not the faceplate.  I can imagine that being a problem for some types of household. 

In reply to Martin W:

If there's one thing VoIP is rubbish at, it's machine to machine comms using tones and DTMF.  Some ONTs like to detect DTMF tones themselves and send them as discrete SIP messages.  What make is your ATA / ONT?

In reply to wintertree:

The network diagram is exchange OLT -> fibre -> ONT -> IP to router from ONT's ethernet port, and also POTS to the house internal wiring from ONT's analogue telephony port.  So basically, you need the ONT by the current POTS point of entry, or some internal wiring will need to be done to get the POTS to where it's needed.  Which is kind-of the reverse of what people had done with DSL where they wanted the router in the lounge even though the point of entry was by the front door and the master socket in the hall.

In reply to Toerag:

Thanks for responding.

Hmm, not sure that's what I wanted to hear!

The ONT isn't here yet, that's due in two weeks' time when the full fibre is run to the property, so  I'm currently testing/experimenting/playing with the VoIP using our existing ADSL+.  If the ONT is going to make a difference then that might be a further complication.

The ATA is a Grandstream HT801.  Andrews and Arnold's support folks have pointed out that there are some DTMF settings on the ATA FXS port.  The relevant section in the user guide https://www.grandstream.com/hubfs/Product_Documentation/ht80x_user_guide.pd... reads:

DTMF Methods
The HT801/HT802 support the following DTMF mode:
DTMF in-audio
DTMF via RTP (RFC2833)
DTMF via SIP INFO
Set priority of DTMF methods according to your preference. This setting should be based on your server DTMF setting.

Which is all well and good, but I have no idea what "my" (presumably A&A's) server setting is.  Maybe I'll have to get back to them to seek clarification?  In the mean time, I've tried all the settings offered and it doesn't seem to make any difference.

I also have a suspicion that those settings only apply in the outbound direction, but that's far from clear - to me, anyway.  What I need is to get DTMF tones generated by the remote device (my mobile) delivered to the device in my house connected to my ATA FXS port, but that ain't happening.  Which is a tad annoying, because from my perspective as a dumb user it's just another sound that needs to get from one device to the other, as happens now with my POTS connection.

I note that the user guide also mentions voice codec options.  Again, I suspect this might be more to do with outbound calling, but I don't know.  Basically, the ATA user guide seems to be written for the 'guidance' of someone who already has a reasonable understanding of this technology and its terminology, which unfortunately ain't me.  If only there was a VoIP 101/For Dummies guide somewhere...

In reply to wintertree:

Data is encrypted between the ONT (consumer end) and OLT (service provider end).  You can look at your neighbour's data but you can't understand it.

In reply to Summit Else:

Yes.

In a world bereft of exploits, flawed cryptography and a looming post-quantum future yes.  In our world….  I suppose it’s no worse than WiFi or cellular in that sense.

There’s information leaked on the activity levels of each person on the shared line simply from the quantity of encrypted packets visible in each TDM slot. Not very consequential, but it niggles!

In reply to wintertree:

Post quantum? You have a quantum computer at home?

You evil evesdropper Mallory listening to your neighbours and solving those private keys!

What makes me chuckle is the brilliance of Deep Thought which needed another computer to interpret it's answer (i.e. what was the question that 42 was the answer) has more than a passing resemblance to needing powerful classical computing to make sense of the quantum one's output.

Hey, where's UKC without a huge digression?

In reply to CantClimbTom:

(Post quantum) future - as in it’s not here yet, but cryptographically protected data recorded now will still be here when that future arrives.

Obvs not.  Used to work in a building with some qubits mind.  

> What makes me chuckle is the brilliance of Deep Thought which needed another computer to interpret it's answer (i.e. what was the question that 42 was the answer) has more than a passing resemblance to needing powerful classical computing to make sense of the quantum one's output.

… although part if the problem was not asking Deep Thought a sensible and well bounded question.   Matching quantum computer interactions to questions is still in its infancy.  

> Hey, where's UKC without a huge digression

It’s a field largely flying under the popular radar but in my view the progress - particularly now error correction is increasingly leading over scale - makes the roadmaps a lot more believable than the hype over LLMs (for example).  Some heavy weight cryptography users are now actively working to secure current data for a post quantum future.

In reply to wintertree:

Well at my work and various people's works there is a concern about the fragility of a lot stuff when quantum computer are out in the wild at enough qbuits to be dangerous. Looks a long way off, but agree that day may come sooner not later

In reply to CantClimbTom:

It’s an exciting time with so many different technologies out there, I wouldn’t want to predict which is going to make it big time.

Even if it’s 40 years off, I expect there’s encrypted material being tapped and recorded now that has a longer half life in terms of sensitivity.

I’ve been contemplating going in to business selling high capacity hardware one time pad units.  The more you think about the technical and operational specifications for such a business the more interesting it gets.  I’m also tempted to sell paper based one-time authentication books along with executive training given the rising threat of AI based spoofing of video calls.

In reply to wintertree:

That would actually require the C‑suite manglement understanding simple instructions on paper, which is not really a given...

Of course, since the smart money is in the overcharged executive training anyway, with them nodding "knowledgeably" at hearing the right buzzwords and pictures, just have a go at it – at least the money would go somewhere else than only into their pockets

In reply to Frank R.:

I was thinking of setting up simulation exercises between executives, hiring Matt Berry to be the antagonist trying to compromise one of them through deception.   If nothing else, it would be memorable…

In reply to CantClimbTom:

Post quantum cryptology algorithms are already here. Just not so many have cut over to them yet.

In reply to Brass Nipples:

Post quantum cryptography has provably existed since the One Time Pad (OTP) was first used in 1882.  It probably dates back in to antiquity over people agreeing shared code words in person.

Various academics and companies are claiming to have modern post-quantum algorithms that don’t need OTPs.  As I understand it, they all use mathematics where there are open theoretical questions.  An implication of which is that the scope for both classical and quantum computers to break the encryption is unknowable until the maths is bottomed out.  If Godel’s incompleteness theorem holds, I’m not even convinced there can be a truely robust system that doesn’t rely on physical exchange of trusted OTPs.  From an information theory perspective different methods would seem to only be able to influence the difficulty, not the possibility, of breaking scheme that don’t rely on a secure, physical exchange of OTPs. (Exchanging quantum states through free space or an optical fibre counts as secure physical exchange, as detection of these by an observer is provably detectable; so hope is not lost for high bandwidth exchange of secure OTPs over large distances, at least under our current, best understanding of quantum physics, which we know to be incomplete…)

In reply to Martin W:

The ONT will probably have an ATA built into it, the network operator doesn't want the hassle of dealing with a load of customer's random ATAs they have no idea how to configure.

Yeah, you can ask them - I assume it's A&A that provide your ADSL and will provide your fibre? However, you're using xDSL which is invariably a bit shit - even good lines are probably suffering loads of correctable errors.  DTMF in audio or via RFC2833 would be the most common methods used. Unless you've got loads of bandwidth any sort of internet activity is going to cause poor speech quality which will upset the DTMF.

If you have the option, set the speech codec to G711 / 64kbps / A-law.  That's the standard old-fashioned telephony codec and most likely to transmit DTMF. Everything else (G729, SPEEX, etc.) is using compression and invariably screws with tones. I assume the mobile can send tones to your gear on the POTS line OK? and it is only failing when trying to send over IP?

In reply to wintertree:

Anything with the words "C‑suite" and "memorable" in them should indeed be quite memorable indeed, but I digress