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i keep meaning to go take some pictures in a couple of exchanges before bt get round to ripping out the 1930s stuff to make room for even more overpriced undercooled equipment racks, i'll post them here if i ever do. my favourite is wembley exchange where they still have all the cold war comms equipment laying around and also shoreditch where the mdf (think patch panel of the gods) is still pin and bobbin rather than modern push connectors so you basically have a 20x100 foot wall of nails, it's loving horrifying in the meantime have this: https://www.youtube.com/watch?v=fp4zlMZVcmM
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Oct 4, 2015 21:19
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Heresiarch posted:when i'm rich and famous i'm going to stop carrying a cellphone and have a model 500 with a rotary to dtmf converter and an answering machine with a tape in it as my only phone because part of being rich is being able to inconvenience other people with bizarre eccentricities you may even be able to get your telco to give you a line capable of pulse dialing - the capability is still there on most modern co equipment it's just turned off in most places
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Oct 4, 2015 21:23
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LUBE UP YOUR BUTT posted:how does that even happen it's happened multiple times in every country on earth maybe not an entire nation but this happened the same year, and blacked out an area and population larger than italy actually a similar thing happened in london shutting down the underground that same year too
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Oct 5, 2015 12:27
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Stubb Dogg posted:Well this is tangentially related to POTS stuff then there were bt phonecards, which were even more low-tech. they looked like this:  those squares with numbers were the actual store of value on the card. a "laser" (actually just an ir diode with a lens) would scan across it, the boxes were ir-translucent but the rest of the card wasn't. when a unit was used the diode would turn up to 11 and melt the lacquer and make the plastic ir-opaque, removing the value from that part of the card and leaving you with a visible sign (like a scratch) of how much credit was used on the card. it was surprisingly secure (although it tended to false-positive, any kind of damage on the face of the card would render it useless) until an someone discovered a particular brand of nail varnish, if applied at just the right thickness, kept the ir-translucent properties and was made opaque by the erase function, but could then be removed with nail polish remover and reapplied, giving you all your credit back also there was another scam where you could use a hairdryer to melt the laqcuer on the front of the card to hide the scratches made by the erase function and sell on the "new" phonecard you "found" for a decent discount off the face value. every school kid in london knew that one, and probably every tourist in london in the eighties at some point bought a phonecard off some fresh-faced cherub after finding all the coin payphones were mysteriously out of order, perfectly capturing the entrepreneurial spirt of thatcher's britain
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Oct 5, 2015 12:54
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fart simpson posted:how old are you? im only 28 and i remember using landline phones during power outages as recently as probably 2004 or 2005 it's still a legal requirement in the uk that land lines are available for emergency calls for up to 24 hours after a power cut, except almost everyone these days has cordless phones so welp. openreach (the bit of bt that owns the last mile) are lobbying hard to get that restriction dropped because diesel is expensive but ofcom are telling them to get hosed for now (because i'm that much of a phonesperg i still have an old corded phone on an extension for just such an eventuality)
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Oct 5, 2015 15:10
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Panty Saluter posted:also a fast charge cell is 5v/2a, so 10w? so a 15w solar panel should get you decent charge assuming no nuclear winter doesn't really matter because most cell towers don't have backup and if they do go into emergency calls only mode to save power i mean i'm assuming we're talking about situations like the 2003 blackouts we were talking about earlier where there's a widespread loss of power, not just "a tramp has pissed on the local transformer so my block is out of power until someone can scrape him off the walls", which was the cause of the last blackout i experienced
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Oct 5, 2015 18:15
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Panty Saluter posted:ya i stayed in a hotel in amsterdam where they wanted 15 euro a day for wifi but you could plug into an ethernet port for free my guess is that they put the ethernet in first then got wifi and never worked out a way of restricting access to the ethernet
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Oct 5, 2015 18:17
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Carbon dioxide posted:Speaking of voice recognition, I actually have a question. It's about cellphones, so kinda offtopic, but whatever. some speech-recognition ivr systems do have a human backup but numbers (apart from nine and five) are ridiculously easy to tell apart electronically even with accents as to your wider question - if i had to guess i'd say that its probably some dumb decision made because they think people are too stupid to figure out the "keypad" button on their touch-tone phones
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Oct 5, 2015 22:40
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mishaq posted:good luck trying to maintain a voip phone call moving between cell phone towers over a data channel atm is still used a lot in the back end because telcos never throw out anything and there's still a shitload of pbx systems out there that don't talk anything more modern also there's no reason at all why you couldn't keep a persistent data connection at handover on (most) 3g and lte implementations (or even hopping between them), but making that work absolutely consistently is hard and it's easier to make customers handle it themselves, particularly as it breaks their pricing model if they let users use their own voip this is only going to get worse once they start selling volte as a premium product even though it's actually cheaper per-minute for them
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Oct 6, 2015 22:35
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Jimmy Carter posted:someone in the bay area keeps slicing fiber backbones (which usually also knocks out phone service) and nobody has a goddamn clue what to do about it after 9/11 almost all the uk telcos decided that for security they had to remove their names from the manhole covers on their ducts in case of cyber attack on the cyber nations cyber security, because of course a cyber terrorist would only want to attack a gxn cyber trunk and not a cyber bt one and would be cyber-defeated by not knowing which one to cyber attack only after they'd spent a year sending guys with grinders around to do this did they realise why they had their names on them in the first place, when it took their engineers 3 hours to find the right manhole every time they had to go out and repair a break, so now every manhole cover in london has a shiny new nameplate epoxied on
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Oct 7, 2015 07:34
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mishaq posted:i don't know what the gently caress you're talking about but atm is still used a lot in inter-carrier links and on the backbone of fixed-line telcos because of lovely old kit that was amortised over thirty years and so is going to get loving well used for thirty years. i wasn't claiming it was used in lte, but even then i'd be surprised if it weren't still lurking on the inter-carrier links of lte networks for the same reason. as to the difference between voice and data, yes i'm aware of that, but the ability to hand over data calls seamlessly has existed almost as long as cellular networks and every cellular data standard currently in use has it. the reason it doesn't happen on some (most) networks is they've absolutely no incentive to get it to work because about the only use-case for it is voip calling and mobile carriers are still stuck in a 1920s billing structure that insists voice gets billed in minutes. the nokia 9500 from 2004 had the capability to keep up a persistent ip connection on handover between wifi, 3g, and gprs (although you needed a nokia box to terminate the far end of the connection) and even (if the network used nokia radios and switches) to automatically and seamlessly route voice over that connection and fall back to the cellular voice network as required - because all of the carriers had only just upgraded though (and really didn't want to rejig their billing to keep those precious minutes up) the capability died on the vine. volte is getting traction because it slices a shitload of overhead off voip-over-cell and, probably more importantly to the carriers, is designed to work with their pricing structures. i'm willing to bet a substantial sum that even when volte is standard worldwide you still won't be able to do seamless data handover though.
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Oct 7, 2015 14:49
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Alereon posted:up until ~2013 i recall denying ss7 connectivity requests for mechanical switches, so im sure SOMEONE still has them, though i believe they are all behind some sort of translation gateway now. i'm sure i heard there are still some places using stowger switches because they had extremely long lines and the stowgers can take a fuckload of current, but i've no idea if that's still the case
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Oct 7, 2015 20:22
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mishaq posted:you can't have reliable voice communication over the radio interface without the networking doing some heavy lifting for you i didn't deny that at all. my point was that it's been possible to do this for a very long time but none of the networks have bothered to properly implement it because (and let's be charitable to them) it's hard to do right, expensive, and has no particular use case that benefits them. the main innovations in volte aren't technical as such but instead in getting buy-in from carriers and handset manufacturers.
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Oct 9, 2015 09:47
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hackbunny posted:I have used atm once on my pc uk dsl providers realised pretty early on that making the dsl connection as removed as possible from the customer was a fantastic idea. bt switched from thomson speedtouch usb modems to efficient 5651 routers (both names that will provoke a mixture of joy and horror in the hearts of greying neckbeards across the uk) even though the latter was about 30 quid more because they worked out it was costing them >£50 per user per year to support the hateful loving things mind you both were infinitely preferable to trying to talk a user through whatever gimped version of the hayes command set their lovely onboard winmodem was deigning to understand and trying to explain to users that no, just because they bought a 56k modem it was unlikely their lovely ten-mile over-pole aluminium phone line was ever going to give them better than 9.6k.
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Oct 9, 2015 10:49
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hackbunny posted:the manta? you mean the manta right? because it was exactly the usb modem I was talking about, whose driver crashed when you unplugged it. an usb device that can't be unplugged. mind still boggles 10+ years later that's the fella the chipset inside it was a for a dsl bridge (one dsl line in, one ethernet out) and the driver was some weird perverted ethernet-over-usb monstrosity with it's own stack so what you technically had was an ethernet port that crashed when it was unplugged
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Oct 9, 2015 11:44
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spankmeister posted:yeah every so often you hear about a evolution of DSL or cable tech and the story is always "with this you won't need fiber" but it's all BS. FTTH is the only way to go forward. that last few hundred yards to the home is a bitch though. for new-build it's getting put in (or at least ducting is), but digging up the roads in a big city is spectacularly expensive (>£100 a metre in some bits of london) and there's just no way to make that expense back on the sort of amortisation you have to follow these days - after the dotcom crash nobody's thinking on thirty-year timescales. the biggest problem though is that the kind of companies with the kind of money to throw around on this sort of thing aren't interested in edge cases and ftth is nothing but edge cases. my company's trialling something like half a dozen access paths (from microtrenching, through powerline networking, to just stringing fibres on telephone poles) but none of them will ever be universally applicable and fttc will be "good enough" probably fairly far into the 2020s. it's not impossible that fttc can take copper pairs up yet another order of magnitude but i don't think anyone's even seriously looking at that at the moment. at least fibre over poles finally gives a workable solution to the digital ghetto problem, there are still fairly major swathes of europe and north america where even 2mbps is a pipe dream, and even though it wouldn't benefit me at all i'd still much rather see effort going into fixing that problem than chasing gigabit speeds for nerds to stream a hundred 4k porn movies at the same time
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Oct 10, 2015 01:30
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Nintendo Kid posted:uh, currently in the us and canada the places where you can't get double digit megabits down are mostly places way too separated to be solved with just putting fiber on some poles. well that's impressive, the figures i saw were i think from 2012 where it was something like 30% of dwellings in the us couldn't get >2mbps. mind you the source of those figures was bt openreach so they could have just been outright lying to make their rural broadband look less poo poo
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Oct 10, 2015 09:27
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ChickenOfTomorrow posted:PUSH BUTTON PHONING https://www.youtube.com/watch?v=oyi_q7hIOmw "and in 40 years there will still be a $2 surcharge for this service despite the technology having proliferated all over the world" and i gather from this thread some people are *still* paying for dtmf calling...
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Oct 10, 2015 21:12
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Shaggar posted:call tracing on tv shows is one of those things that always annoys me. its one of those things where either you have the data already and when the call is turned up you instantly know the source or you don't have the data because the phone company doesn't have it so its gonna take a few weeks for them to do a tag and locate. well with number portability it can be a bit more complex than that, you might have to bounce around half a dozen operators before you can actually get the user data. Powercrazy posted:back in the day tracing a call involved calling multiple different COs and giving them a time and trunk number and they would manually go through the logs switch by switch until they found out it was from a phone booth across from the police station. there's a tiny amount of truth in television in that old "keep them talking" thing though - you could get the operator to trace the trunk back as long as the line stayed open.
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Oct 12, 2015 19:26
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thehustler posted:You know years ago in the UK some freephone numbers didn't have a number to call, you just dialled the operator on 100 and asked for "Freephone <company name>" - what the hell was that all about? short answer - british telecom payphones had no other way of bypassing the coin-request apart from calling the operator - freephone calls were actually just reverse-charge calls to a fixed number at a discounted rate the longer answer is basically that but also throwing in the advanced state of decrepitude of large parts of the old gpo network meaning that quite a lot of large companies outside of london were unable to run their own automatic pbx so these were actually station-to-station calls to an operator at the destination who would then connect to an available agent - the discount on the freephone system was cheaper for bt to give than to actually fix this. there was also a rumour that bt were deeply suspicious of automatic freephone systems because they were the entry point for an awful lot of phreaking activities in the us when they were introduced there - certainly this would match with the software (possibly too grand a word as most of them were still electro-mechanical) in payphones that locked out dialling of any number not beginning 1 or 9 without cash going into them, and the local exchanges that similarly would only allow 1- or 9-prefixed numbers nowhere but the local operator.
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Nov 23, 2015 09:17
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neatly tying up "misfiring phone calls" and "remember when isps sent out cds", back in the days of free dialup isps in the uk (free as in no subscription fee, you paid through the phone bill) one of them put an install cd on the cover of a magazine. unfortunately they'd not actually bothered to test it apparently, because they (in an attempt to add 1470 as a prefix to the dialup to force clid to be passed by customers who withhold it, because that was the only way they could actually id users without a billing relationship) actually managed to add 00147, leading to some poor fucker in the states getting thousands of modem calls a day, as well as of course a bunch of users having to pay international call rates
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Nov 29, 2015 11:17
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fishmech posted:this couldn't have gone to the states, unless this happened very recently. it would have been 478 as it was an 0845 number, and free dialup isps were still a thing until well into the mid naughties.
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Jan 5, 2016 01:44
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fishmech posted:well you might as well just say the whole number at this point, being 478 area code and a 45x exchange means it would be somewhere in Macon, GA if it really was an active number. iunno, it was over a decade ago and not even at a company i worked at and i'm not spending days on google to score internet points, what would be the point of that?
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Jan 5, 2016 08:28
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LastInLine posted:it is. its mainly for sports and conservative talk radio where the fidelity of fm isnt needed but the range of am is low-power am licenses are also used a lot in the uk by religious buildings (churches and mosques mostly) in built-up areas so they can transmit the bells/call to prayer to locals without breaking noise-abatement rules of course a lot of them are moving to fm because it seems like the only place you can find an am receiver is on a cheap car stereo
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Jan 5, 2016 13:05
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| # ¿ Apr 29, 2024 03:03 |
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BangersInMyKnickers posted:ATSC is going to be kinda ownage because its going to an IP multicast carrier with h.265 data and so the number of channels/audio carriers/whatever you want to jam in your frequency band is exclusively dictated by the amount of bandwidth and what resolution/bitrate you chose to broadcast in. so you could do like 4 1080p channels, or 1 UHD channel and maybe 1 additional SD channel, or 16 SD channels, or whatever other combo inbetween you can dream up wait i'm confiused i thought you were talking about a broadcast standard in which case your second part just describes a mux which is how like all digital broadcasts works, so what's with the ip layer in there?
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Jan 7, 2016 23:53
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