[HN Gopher] Telephone Line Rural Outside Plant
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Telephone Line Rural Outside Plant
Author : Bluestein
Score : 176 points
Date : 2024-09-02 07:21 UTC (15 hours ago)
(HTM) web link (cityinfrastructure.com)
(TXT) w3m dump (cityinfrastructure.com)
| ale42 wrote:
| I love landline phones (when they work right, which is not the
| case everythere) because usually they have better sound quality
| than mobile (which can be good-to-horrible depending on network
| quality) and almost zero latency.
|
| But it's time to switch to fiber optics!
| Bluestein wrote:
| Totally.-
|
| PS. But, can you do fence-wire comms with fiber? :)
| ale42 wrote:
| > PS. But, can you do fence-wire comms with fiber? :)
|
| Maybe with a transparent plastic fence :-D
| Bluestein wrote:
| There you go.-
|
| (But your fence bend radius is limited, though ... :)
| schiffern wrote:
| We often talk of developing nations "leapfrogging" landlines
| and going straight to mobile, but they're also going straight
| to fiber. It would be fascinating to see this same type of
| breakdown for rural fiber infrastructure.
|
| One obvious difference is that fiber can't self-power a phone,
| but with ubiquitous mobile phones/solar panels/powerbanks that
| doesn't strike me as a huge show-stopper.
|
| Thanks OP, great post and content. Now I'll go through the
| world with new eyes!
|
| EDIT: found the fiber page
| http://cityinfrastructure.com/single.php?t=Fibre%20Optic%20C...
| Bluestein wrote:
| Interesting, the "straight-to-fiber" leapfrogging. Was not
| aware. Makes sense.-
|
| I'd be interested to know - qua infra - what their _power
| grids_ are looking like ...
| detourdog wrote:
| Estonia when it left the Soviet Union was offered a used
| phone system from a country that wanted to upgrade. Estonia
| decided to build new.
|
| https://theconversation.com/estonia-is-a-digital-republic-
| wh...
| Bluestein wrote:
| Smart move.-
|
| PS. Also, interesting that there - apparently - is a
| "second hand" market for used phone systems. As in,
| wholesale.-
| detourdog wrote:
| Obviously excepting the cruelty I love the modern world.
| I marvel at the organization and patterns.
|
| The Soviet Union was suffering some food crisis in the
| 90's. One morning the news was discussing Clinton
| granting food aid to them. That same morning as my subway
| crossed by the Dominoe sugar factory there was already a
| Russian ship docked.
|
| That was such a strange cause and effect moment for me.
| johannes1234321 wrote:
| It's interesting with East Germany - after German
| reunification it was covered with fiber. However then DSL
| became the standard way of going online in Germany, while
| that doesn't work on fiberand with only few to no
| consumer priced offerings for FTTH many areas were left
| out from "fast" Internet for a while, while having the,
| in theory, superior net.
| detourdog wrote:
| My guess it was the asymmetry that was the attraction of
| the DSL. If everyone has equal access to bandwidth the
| message is harder to control.
| xattt wrote:
| Cell phone coverage has been abysmal in my part of the world,
| to the point where 911 calls can be unreliable (1).
|
| (1) https://www.cbc.ca/news/canada/prince-edward-island/pei-
| cell...
| gary_0 wrote:
| The telecom situation in Canada is ridiculous. Even in
| Greater Vancouver, the 3rd largest metropolitan area in
| Canada and the 34th in North America, there are dead zones
| everywhere with major providers. I'm in a suburban
| development that was mostly built in the last 5-10 years,
| and there still aren't any towers near here so my bedroom
| and foyer have no reception (not 1 bar, I mean my phone
| says "no service, you must be in the wilderness"). I have
| to stand by a window to make calls. And this is a wood-
| frame building on flat terrain, next to two major highways.
| simfree wrote:
| Telus, Bell and Rogers are ingrained in the minds of
| Canadians as the only options.
|
| Almost all attempts to change that over the years have
| failed or have not been able to get sufficent market
| penetration to become self funding for rapid growth.
|
| Canadian investment funds would rather go and buy U.S.
| ISPs from failing ventures like Frontier (creating Ziply
| Fiber) than investing in Canada because they know how bad
| the situation is. Getting sub-30% market penetration when
| offering, better, less expensive fiber internet makes the
| Canadian market uneconomical for deeper investment by
| insurgent ISPs.
|
| The Canadian consumer is easily swayed by
| Bell/Telus/Rogers propoganda like https://web.archive.org
| /web/20140402040045/http://fairforcan...
| elzbardico wrote:
| There's also a lot of replacing copper cabling with fiber due
| to copper cables being frequently stolen.
| mschuster91 wrote:
| > I love landline phones (when they work right, which is not
| the case everythere) because usually they have better sound
| quality than mobile (which can be good-to-horrible depending on
| network quality) and almost zero latency.
|
| That was the _old_ landlines, of actual POTS, era. Back then,
| there was a direct electrical circuit literally switched using
| relays between both participants in a call, with only
| amplifiers, switches and power sources in between. More modern
| systems used banks of relays, and then it all went downhill
| quality-wise.
|
| First, the telco core systems were replaced with digital trunks
| that had ADCs on both ends of a call in the regional
| distribution center, and consumers were switched over to ISDN
| for telephony. Then, the analog/ISDN frontends moved to the
| curb side where ADSL, VDSL and nowadays G.fast frontends were
| added to the mix, which were connected to the telco network
| using fiber. Then, analog and ISDN were shut down, with voice
| phone calls being migrated to VoIP.
|
| And nowadays, it's the full evolution with GPON - on the telco
| side, there's only fibers and a single TX/RX pair of
| transmission modules serving up to 64 customers. What used to
| require a whole multi-story building can now be done in the
| space of a better-quality shed. And the analog frontend is only
| at the CPE, if there is an analog frontend present at all and
| it's not VoIP softphones or DECT.
| Dibby053 wrote:
| My new ISP took this to another level: if you transfer your
| landline phone number they send you a voice-only SIM card and
| a 4G router into which you're supposed to plug your landline.
| Calls to the landline number are redirected to the number in
| the SIM (with a significant delay). I wonder why they did it
| this way instead of implementing VoIP, especially since the
| all-in-one GPON/Wi-Fi router already has a landline port.
| actionfromafar wrote:
| Maybe requirements on availability?
| dfc wrote:
| What ISP do you use?
| toast0 wrote:
| In the US, at least in the states I lived in, ISDN telephony
| was always niche, the price was too high unless you needed it
| for a remote studio, or you had a teleconference setup or
| needed the blazing fast 128kbit dial up experience.
|
| Analog phones with a digitizer at the central office or
| remote terminal is still a very good calling experience with
| minimal latency. 8-bit u-law @ 8000 Hz isn't great audio
| quality, but the sampling delay is near zero, and when it was
| all PRI digital (t1/isdn/etc) switching, multiplexing was
| done per sample, so there was no significant buffering (a two
| sample buffer would be sufficient at any switching point).
|
| Mobile uses complex compression with significant sampling
| delay and sends data in bursts so there's packetization
| delay. VoIP often uses complex compression (but you can
| configure for u-law) and is usually 20ms packets, plus you've
| got to add a jitter buffer to account for packets taking
| different amounts of time to traverse the network.
|
| Packet switching clearly won over circuit switching, but
| we've lost the very low latency local calling we used to
| have, and I don't think anyone is willing to send 1000
| packets per second for voice calls to get close to where we
| were. For long distance calling, probably improved routes
| that were run for packet switching reduce latency enough to
| cancel out the increased factors.
| freeopinion wrote:
| I'm not sure what you mean by "better-quality shed" but
| cabinet sizes today are often less than 1 cubic meter. I
| guess you know that, but thought it might surprise some
| people.
|
| One cabinet doesn't really replace a multi-story building.
| Many cabinets spread out over the service area do the job.
| But each cabinet can perform all the functions that used to
| happen in the large building. They just make it economical to
| perform those functions for 100 - 1000 subscribers, instead
| of having to centralize them into a single location that
| serves 5,000 - 100,000.
|
| Those cabinets are not a result of fiber. They were more a
| necessity of high bandwidth services without fiber. Think
| ADSL. Fiber actually makes it possible to go back to more
| centralized service while providing even more bandwidth. You
| can deploy passive fiber splitters in an old-fashioned
| pedestal and keep the active optics in the multi-story
| building for 100,000 subscribers again.
|
| Maybe you meant that the active optics would only fill a
| small shed's worth of space in that old building. I finally
| caught up to you.
| fleventynine wrote:
| With 64 XGS-PON customers per SFP+ module, the only active
| equipment you need to terminate connections for over 60,000
| customers fits into a single rack. Large centralized
| buildings are largely obsolete unless you want to offer
| services beyond basic Internet access.
| mschuster91 wrote:
| The large space savings IMHO come from getting rid of the
| point to point connections via these massive 2000+ wire
| cables and their corresponding patch panels and routing
| infrastructure. With GPON you only need a single SFP module
| and passive optical splitters in the underground buried
| junctions, no need for any roadside equipment.
|
| (Worked as a trench digger / roadside equipment box
| installer once in younger times)
| razakel wrote:
| It was time to switch to fiber 50 bloody years ago.
| marcus0x62 wrote:
| > But it's time to switch to fiber optics!
|
| The PSTN has been hybrid fiber/copper for decades. The vast
| majority of inter-CO traffic is carried on fiber optic lines.
| Many POTS lines are carried on fiber optic carriers from the
| central office to a subscriber loop carrier or similar device
| and then only travel a short distance to the subscriber
| premises on copper lines.
| zabzonk wrote:
| in the UK it is typically fibre to the box on the street, and
| then copper from that to the house. providers would love you
| to subscribe to fibre to the house (so they can charge you
| exorbitant prices for it), but really YAGNI for most people
| at least in my experience.
| sgt101 wrote:
| That used to be the case - but it's rapidly becoming
| standard to be directly connected to fibre. I believe that
| something like 60% of UK premises have a fibre connection
| available and I expect that all the providers will push
| folks off copper as fast as they can.
|
| Because copper is a pain in the arse compared to fibre (for
| the provider). For the consumer copper has one key positive
| that fibre just doesn't - it works in a power cut.
| lxgr wrote:
| In Germany, in particular in the former East, fiber
| development inadvertently got in the way of fast home
| Internet access for many years:
|
| Many regions were built out with (at the time of the German
| reunification) state-of-the-art hybrid fiber/copper systems,
| with fiber extending even beyond the central office.
|
| Unfortunately, the technology used is incompatible with DSL,
| the access technology of choice of the former incumbent
| operator, so any landline deployed using it was ineligible
| for anything faster than dialup until they either built out a
| copper link to the central office, or upgraded the existing
| fiber to GPON (which didn't happen until very recently).
| ale42 wrote:
| > The PSTN has been hybrid fiber/copper for decades.
|
| Definitely, I was mainly thinking about those thousands of
| lines coming out from the CO...
| linsomniac wrote:
| If you think POTS sounds good, you should try ISDN, it'll knock
| your socks off! Back in the mid-90s I got ISDN BRI (2x64Kbps
| channel) service in to replace analog modem service. It would
| connect in well under a second, and while connected at 128K we
| could receive a phone call (dropping one of the channels, so
| having voice plus 64K data), and the phone calls sounded quite
| good.
|
| It used to be that for recording remote interviews or even I
| believe just general voice recording like audio books, the
| media companies would have you come into a location that had
| ISDN, and if you were a real big timer you might have ISDN in
| your home studio.
|
| That was back in the day when they gave a crap, then the
| pandemic came along and the media companies seemed to be happy
| throwing any crappy video chat up for broadcast, not matter how
| echoy the room you're in or how many drop-outs.
|
| WRT fiber optics, we are just now starting to see Q.com
| (Century Link) deploying fiber to the neighborhoods. Up in
| Canada in a similar sized city they deployed fiber back in
| 2000, but in the states QWest wouldn't do it because, I've been
| told, it would open up allowing CLECs to put DSL equipment in
| neighborhoods, and let them cherry-pick neighborhoods to offer
| service in. Finally a few years ago the city stepped in a ran
| fiber to every house, which honestly is a better option IMHO.
| shepherdjerred wrote:
| I've had Quantum Fiber in Seattle for a year or two now. It's
| fantastic! Symmetrical upload/download, no data cap, 1gbps,
| and I pay something like $75/mo.
|
| I was paying $100/mo to Comcast for the same thing, though I
| had 1.2gbps down/35mbps up.
| wrycoder wrote:
| Is your endpoint routable? Is the IP fixed or dynamic?
| volf_ wrote:
| Yes. Dynamic as the IP is renewed everytime your device
| resets
| linsomniac wrote:
| Good to know, I was passingly wondering what the service
| level was that they were offering. CenturyLink currently
| can only offer me 60Mbps/5Mbps for $55/mo, until Q.com
| builds out more of the town.
|
| That compares poorly with the city FTTH which is 1G/1G for
| $70/mo, 2G/2G for $100, or 10G/10G for $200/mo. A static
| IPv4 is another $20/mo (which is admittedly pricy for an
| add-on, but $90/mo for gig with static feels fine to me).
| tjohns wrote:
| Or if you want something that you can actually get (since
| it's impossible to get a new ISDN line as a consumer), you
| could do VoIP with G.722/Opus or cellular with HD Voice (AMR-
| WB). The quality is honestly on par with ISDN.
|
| And yes, ISDN is still the gold standard for remote voice
| acting work, but as ISDN lines have gotten more difficult to
| order a lot of folks have been moving to VoIP. I've heard an
| app called Source Connect is popular in the broadcast
| industry, and supposed to provide equivalent quality to ISDN.
| ape4 wrote:
| Naive question: Was fiber always digital? I could imagine
| varying the intensity of the a laser signal to send sound.
| zabzonk wrote:
| but ... why?
| declan_roberts wrote:
| I can't imagine that subtle light intensity would survive the
| various light amplifiers used along the way.
| ooterness wrote:
| Analog signals won't survive a 1000km undersea cable, but
| for a few kilometers you don't need amplifiers at all. The
| loss-per-meter of optical fiber is much lower than a coax
| cable.
| ooterness wrote:
| Radio-frequency over fiber (RFoF) signals are usually analog.
| By intensity-modulating the laser, it's relatively easy to
| convert a GHz-wide analog signal from electrical to optical
| and back.
|
| https://en.wikipedia.org/wiki/Radio_over_fiber
|
| https://www.rp-
| photonics.com/radio_and_microwave_over_fiber....
| Dead_Lemon wrote:
| I've been enjoying the videos of 'Look Mum No Computer', building
| his own 60's based, electromechanical telephone exchange, is his
| Museum of everything else.
| https://www.youtube.com/watch?v=tK1lH8pjXTo
|
| His second channel has some more dedicated content on telephone
| systems,
| https://www.youtube.com/playlist?list=PLKnS0AB2CTN_eu8k8rgaO...
| He has spent a fair amount of time building it out, from
| initially receiving his first exchanging and getting it to work,
| and adding more to it
|
| It fun just to watch how the system selects lines and routes
| around the exchange. Other interesting things, like how the dial
| and engaged tones are generated, and how prerecorded messages are
| played back to a number that is no longer in service, something
| like, 'This number no longer exists, please try again'
| hyperbolablabla wrote:
| So phreaking cool
| jagged-chisel wrote:
| iswydt
| volf_ wrote:
| Also check out https://www.youtube.com/@ConnectionsMuseum
|
| The channel is about the fully functional Central Office turned
| Museum in Seattle
| hiatus wrote:
| I don't know if it's just me but the playlist link you shared
| just redirects to the homepage.
| Jordan_Pelt wrote:
| I really want to see the insides of those buildings.
| volf_ wrote:
| https://www.youtube.com/@ConnectionsMuseum
|
| There's a fully functional system deployed in Seattle as a
| Museum
| mjcl wrote:
| There's some videos on the AT&T Tech Channel on YouTube that
| show inside the CO, like this one for the "Speedy cutover
| service": https://www.youtube.com/watch?v=saRir95iIWk
| strivingtobe wrote:
| TIL the origin of the term "cutover" for IT migrations.
| Fascinating!
| Bluestein wrote:
| I really do hope y'all excuse my ignorance, but ...
|
| ... what part of the "switchover" process is this? That is to
| say ...
|
| ... I get that you have to cut to switch over but ... what
| would come next? Does the new system get spliced in? Is it
| already wired - pending just the cut? (Thus the speed with
| which it is done) ...
| icehawk wrote:
| the new system is already spliced in, but is electrically
| isolated.
|
| the old system can't be isolated like that so they have to
| physically cut the wires to it before they electrically
| connect the new system, which is the switch throw at the
| end of the cutover.
| Bluestein wrote:
| Makes sense. Thanks!
| WarOnPrivacy wrote:
| _Now we get to a really interesting part. As you drive along
| rural roads, you 'll see what appear to be paint cans, each with
| a this cable coming out the top._
|
| _As you might have guessed, these therefore are not paint cans,
| but are the enclosures for the loading coils. If there is a
| 600-pair cable, then you need 600 loading coils (these look
| something like little spools of thread), and you need to attach
| each to the feeder cable._
|
| I hadn't seen that config before. (looong-time infra
| rubbernecker). I assume I've seen variants but am not recalling
| what they look like.
| kibwen wrote:
| _> Here 's a close-up of the 1,200 pair cable._
|
| Terminating that must be a lot of fun. Please tell me they have
| some clever device that makes this task easier.
| paradox460 wrote:
| They had splice tools, but you were still threading cables to
| each other by hand.
|
| The model train club I used to be a member of was full of old
| telephone guys, and they'd share old stories
| sgt101 wrote:
| Yeah - there are colour codes you can use to find the pair that
| you want to connect, they are arranged in a mystical system of
| binders. It's like a map.
| zikduruqe wrote:
| Back in my telephone days, I used to use this to remember my
| pair colors.
|
| We Rape Beautiful Young Virgins (for the White Red Black
| Yellow Violet) and Big Old Gob of Bull Shit (Blue Orange
| Green Brown Slate). There were other mnemonics other people
| used.
|
| https://en.wikipedia.org/wiki/25-pair_color_code
|
| Back in my younger days when I ran a switching office, I used
| to rip a few bong hits, put on some music and wire DSX panels
| on the weekends and just zen out. It was therapeutic.
| sgt101 wrote:
| uhmmm ok....
| ssl-3 wrote:
| The way to terminate a 1200-pair cable is the same as eating an
| elephant: One bite at a time.
|
| Historically (and in the US, at least), telephone wire has been
| organized into chunks of 25 pairs each, with each pair of wires
| having a unique color code.
|
| And every 25 pair cable in a given system has the same set of
| wire colors.
|
| And these 25-pair chunks are easy to terminate on (say) a 66
| punch-down block. It takes some time to learn how to get good
| at it, but not as much time as one might think.
|
| Those 25-pair chunks are organized into 5 different body
| colors, each with 5 different pair colors.
|
| We're all familiar with the colors of 4-pair cat5 and friends;
| that's just the first 4 pairs of wire of a 25-pair chunk. (We
| can tell that they're the first 4 pairs because they all have
| the color white in common with eachother.)
|
| So, the order for a 25-pair cable is this:
| First, the white pairs: Blue, Orange, Green, Brown, Slate.
| Then the red pairs: Blue, Orange, Green, Brown, Slate.
| Then the black pairs: Blue, Orange, Green, Brown, Slate.
| Then the yellow pairs: Blue, Orange, Green, Brown, Slate.
| Then the violet pairs: Blue, Orange, Green, Brown, Slate.
|
| Done. A 25 pair cable is terminated.
|
| ---
|
| Larger cable are also organized into 25-pair chunks. The colors
| of the binder strings wrapped around each 25-pair chunk
| identify it.
|
| This works for cables with up to 600 pairs.
|
| ---
|
| 1200-pair cable just consists of two 600-pair groups, with each
| group wrapped in its own colored binder
|
| ---
|
| So to begin terminating a 1200-pair cable, first you identify
| the first group of 600, based on the color of outermost binding
| wrap. Now the 1200-pair problem is only a 600-pair problem.
|
| Inside of that group of 600, find the first chunk of 25 (the
| white-blue one). Now your 600-pair problem is only a 25-pair
| problem, and terminating 25 pairs is easy.
|
| So terminate all 25 pairs, and then move onto the next chunk of
| 25 (white-orange).
|
| Keep doing this until you've worked through all 24 chunks of 25
| pairs in that 600-pair group.
|
| And then just do it again for the other 600 pairs.
|
| []:
| http://cityinfrastructure.com/OutsidePlant/Webfiles/colorcod...
| paradox460 wrote:
| As a kid in Los Alamos, the mesa I lived on was far enough from
| the central office[1] that it had some loading coils between us
| and them. This meant that we couldn't get DSL on that mesa. The
| mesa across the way didn't have the loading coils, and thus was
| able to get DSL. I remember the jealousy of my friend being able
| to download DOOM WADs in a couple of seconds, while I had to
| schedule them, or convince my dad to download them on the much
| faster connection at LANL.
|
| Eventually we managed to get either an ISDN line or a T1 line, I
| cannot remember which, but shortly thereafter Cable internet
| became available, and rendered the whole problem moot.
|
| [1] Los Alamos had one central office, with a big microwave relay
| in the top of it: https://i.imgur.com/Lcfj9oA.jpeg
| SoftTalker wrote:
| I didn't know that these cables are all pressurized with air to
| keep leaks out (and to dry out any leaks that do happen). To me,
| that was honestly the most interesting thing in the article.
| russfink wrote:
| A lesson in how not to use parentheses in technical writing.
| JSDevOps wrote:
| Cool read
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(page generated 2024-09-02 23:00 UTC)