Earlier quoted context omitted.
I know there are some telecom folks on here that may be provoked to correct me but pulp was standard before the advent of cheap plastic insulation in the 1950s on up. I live in the midwest and my brother is a lineman for AT&T. There is an astonishing amount of pulp-insulated phone line still in service today. In order to keep it dry, the conduit that the pulp lines are run through is pressurized to 5-10psi. Anyone th…
> I know there are some telecom folks on here that may be provoked to correct me Aka Cunningham’s law > Any kind of outage on the compressor or dryer I’m confused: isn’t a bigger concern any physical damage to the conduit anywhere in the run that is too large for the compressor to overcome? Or are we talking football-field-sized compressors here?
ADSL works over wet string (2017)
51–60 of 157 posts
Re: ADSL works over wet string (2017)
#52That fact that this delivers 3.5 MBit/s really makes you wonder how many low speed connections out in the wild are literally broken cables that still have some amount of coupling somewhere.
Potentially apocryphal, but Telstra's copper cable network supposedly had its insulation made of paper, not rubber. I remember when it rained the curbside pits fill with water, causing slowdowns and frequent ADSL dropouts (until things dried out).
It took over a year for Ziply to repair the land line of my 90-year-old parents. 30+ hours on the phone with support, multiple visits by techs who were simply not interested in doing any work. I had a tech tell me, literally to my face, "this line is working fine" when the line was stone dead. Another told me that I had to buy all new phones because the ones my parents had were "out of date". (To humor him, I bought a $15 phone from a local electronics store, plugged it in and showed the tech that it wasn't working. He did nothing).
I have now learned that the WA state utilities commission is pretty interested when providers try to pull stunts like this. You can also dig out useful company contact information from the commission's website.
Re: ADSL works over wet string (2017)
#53Our homes' water supplies are untapped options for data connectivity.
joking aside, I remember a while back that there has at least been cursory investigation into running high-speed internet cables through water pipes. Presuming you have water pipes to your property, could be easier than digging up roads etc. Only issue might be if you have a leak and need to shut off your water!! https://www.theguardian.com/technology/2021/aug/09/uk-launch...
The linked article (and government push to do this) completely ignores the fact that this is done frequently now.
It's used to get the last few metres into the home, e.g. from the boundary to the inside of the house. You put a swept tee in at each end, after the stopcock. Water off, dig down adjacent to stopcock, cut pipe, shove a drinking water rated duct down the pipe through the small port on a swept tee. Shove some chlorine tablets in the pipe and couple up to the new swept tee. Repeat interception at other end outside or indoors, and then use standard fibre cable blowing through the inner microduct, and away you go.
There's a huge amount of disused water pipes in most developed nations which are frequently used, similarly using sub-ducting, and you can run cable through mains - but have to come out every time there's a valve, so practically it's usually cheaper to dig. Where it comes in handy is where there's areas you can't practically dig up, e.g. major roads with old pipes underneath.
Source: Have done a bunch of this for a major UK telco.
Re: ADSL works over wet string (2017)
#54Earlier quoted context omitted.
The cable analyzer is showing about 55db of loss across 2 meters. That's about equivalent to the loss across 4km of "good" copper.
I kid, the issue was solved some time ago - a telecom engineer pinned it down to a soggy junction box.
That’s funny because my SO’s parents have 1.5Mbps DSL by contract. For only $100/mo they can jump up to 12Mbps. USA and 1 hour from me where I have gigabit docsis 3.1.
If they had 1Mbps because of a fault that would be more unfortunate than unfair.
Re: ADSL works over wet string (2017)
#55This thread is a good reminder to be very thankful for my £20/month unmetered 1gbit central London FTTH.
Re: ADSL works over wet string (2017)
#56Can ADSL survive an acoustic coupler? To give it a fair shot, assume the driver and microphone are studio quality rather than the kind you’d find on a 1970s telephone handset. I bet it’d work pretty well. But the real question would then be: how much of an air gap could you create and still get a connection? Could you post to HN on an ADSL signal that’s being screamed across the length of the room you’re sitting in?
ADSL upstream starts at 25kHz, downstream at >120kHz. So probably not. Purpose-designed ultrasonic hardware might be able to.
Not sure if this is within the spirit of the question, but: The individual ADSL bands are only 4 kHz wide, so you could modulate 4 or 5 of them down into the audible range (20Hz - 20kHz) and back up again after the transmission through the acoustic coupler. In theory, ADSL should then pick those bands to transmit the data.
Re: ADSL works over wet string (2017)
#57That fact that this delivers 3.5 MBit/s really makes you wonder how many low speed connections out in the wild are literally broken cables that still have some amount of coupling somewhere.
Potentially apocryphal, but Telstra's copper cable network supposedly had its insulation made of paper, not rubber. I remember when it rained the curbside pits fill with water, causing slowdowns and frequent ADSL dropouts (until things dried out).
Many parts of rural Prince Edward Island (PEI) has DSL running on a phone system that’s probably original from modernization initiatives in the 1960s - 1980s. Party lines were the norm in some areas up west until late-1980s.
Re: ADSL works over wet string (2017)
#58Discussed at the time:
ADSL over wet string - https://news.ycombinator.com/item?id=15908107 - Dec 2017 (88 comments)
Re: ADSL works over wet string (2017)
#59I'm pretty sure this is exactly how my ATT DSL comes in.
Re: ADSL works over wet string (2017)
#60I remember in the 90s when we were deploying a business campus, we first used ADSL services from the local carrier, but not for long.
We discovered we can get "dry lines", basically just rent copper run from site-to-site, nothing on it from local carrier. Slap ADSL modems on each and we got max throughout, at a fraction of the cost. Then we upgraded to SDSL, and that was like hitting the jackpot.