A brief history of barbed wire fence telephone networks
loriemerson.net
loriemerson.net
At one point someone rung down the line and was answered "jawohl?" ..... hung up immediately ..... seems the germans were doing the same thing, path of least resistance was the 2 copper wires ... they found a German speaker to listen in until the front moved
Those old timers told some great stories, don't know how true this one was, it's at least plausible
http://cityinfrastructure.com/single.php?d=RuralOutsidePlant...
Lastly, the sensors identify pressure dips, which tells technicians roughly where the leak is. Then they know which portion of cable to repair or replace.
The cycling of the compressor, and the periodic click-hiss of the dual-column desiccant dryer, was an ever-present noise in the basement of every CO. Somewhere over near the air plant, would be a rack full of panels of pressure and flow gauges, and a bundle of tubes taking them over to the individual sealed splice closures where the air was injected into the cables.
A cable pressurization logbook sat on a shelf in the gauge rack, and one of the CO tech's duties was to periodically (weekly?) write down the readings from all the gauges, and compare them to last week and last year. Significant increases were handed off to the outside-plant crews.
At some point, typically where the branched cables ended at cross-connect boxes, the end of the cable would be sealed (air blocked by epoxy potting around the end), and the small lines leaving the crossbox would be icky-PIC instead of pressurized.
I'll provide one of my favorite civ-infra resources, Practical Engineering[1]
Barbed Wire Fences Were An Early DIY Telephone Network - https://news.ycombinator.com/item?id=7007445 - Jan 2014 (1 comment)
Barbed Wire Telephone Lines Brought Isolated Homesteaders Together - https://news.ycombinator.com/item?id=15951230 - Dec 2017 (24 comments)
Old-time ranchers used barbed-wire fences as phone network - https://news.ycombinator.com/item?id=19506811 - Mar 2019 (1 comment)
Barbed wire fences were an early DIY telephone network - https://news.ycombinator.com/item?id=30231837 - Feb 2022 (64 comments)
Worth a listen!
With network monitoring we could now detect breaks in the fence at a 1 mile increment to let the ranch hands know where to go and when it broke.
One other thing I remember from those stories was a lot of the systems were wired in a way that picking up the phone would cutoff anyone farther down the line - so no party line snooping which I remember doing in the 1970s and early 1980s on the phone at my grandmas farm in rural southern Indiana.