6 ms·

Around 2014 or so, we (light infantry) had field telephones on the books, but we only used them once for a field exercise to practice assuming all modern tech w

by sa46 3y ago

Around 2014 or so, we (light infantry) had field telephones on the books, but we only used them once for a field exercise to practice assuming all modern tech was down.

H8crilA 3y ago
WW2 stories of diversions to enemy communications: put small needles through the cable. At first you'd think you just have to cut the cable, but that actually makes it very easy to find and fix the problem. Small needles that short the wires are very difficult to locate. Unless you have a fast device that measures return latency on the shorted circuit, but that wasn't available in the 1940s.
- bradknowles 3y ago
  It's called a Time Domain Reflectometer. They're pretty cheap. For RG-58 style coax, you can get hand-held VeEX CX41 units for a few hundred dollars. I'm sure that TDRs for other types of cables shouldn't be too much more expensive.
- jutrewag 3y ago
  Perfect time to use a pin nailer.
  - tonyarkles 3y ago
    Customers used to do this unintentionally with staples, and my boss was too cheap to buy a TDR tester for a long time
- tialaramex 3y ago
  However "a fast device that measures return latency on the shorted circuit" is presumably very cheap today. 20+ years ago, rewiring buildings for 1000baseT the Cisco switches (3650s maybe? 3750s? I know they had IPv6 multicast acceleration in the switch fabric because that's why we had them) would do this for any circuit on command, OK, 18 metres from here there's a fault, pace, pace, pace, I reckon it'll be up on this cable tray... yup, some fool tried to "repair" a broken Cat5 cable, we'll just rip it out, meanwhile patch to a different circuit.
  - sandos 3y ago
    I believe I even had a BIOS in a PC that did this in some way.... Actually, I think it wasn't detecting faults but rather the length of cable connected.
  - jmole 3y ago
    Time Domain Reflectometry - https://community.cisco.com/t5/networking-knowledge-base/how-to-use-time-domain-reflectometer-tdr/ta-p/3119327 https://community.cisco.com/t5/networking-knowledge-base/how...
- cjbgkagh 3y ago
  You can use binary search to find the pin. Unless two or more pins are used.
  - monocasa 3y ago
    At that point it's easier just to run new line.
    - cjbgkagh 3y ago
      But you don’t know that when you start. You could assume it and never try to repaid and always replace but in WWII there were not as many options.
UncleEntity 3y ago
We used field phones all the time when I was in light infantry (82nd Airborne). Pretty much any time we were in a fixed position out would come the commo wire so as to not give our position away. They even went as far as having us string wire out to our ambush sites when we were on the Iraqi border during the first gulf war and reel it back up when we came in. Zero radio signals out there because they didn’t want them to know that a whole division plus French armor was there. Modern tech is good and all unless you have some dumb Joe that keeps erasing the codes out of the radio by turning on the truck without putting it on standby or something…never quite figured that one out.
- sa46 3y ago
  All the way! I was 1-505 PIR. > dumb Joe that keeps erasing the codes out of the radio by turning on the truck without putting it on standby Oh man, I have nightmares about comms. Juggling frequencies while traversing areas of operation, trying to get satcom working in mountainous terrain with jammers, and depending on the finicky windows-tablet encryption device, was not a fun time.

by sa46 3y ago

Around 2014 or so, we (light infantry) had field telephones on the books, but we only used them once for a field exercise to practice assuming all modern tech was down.

H8crilA 3y ago

WW2 stories of diversions to enemy communications: put small needles through the cable. At first you'd think you just have to cut the cable, but that actually makes it very easy to find and fix the problem. Small needles that short the wires are very difficult to locate. Unless you have a fast device that measures return latency on the shorted circuit, but that wasn't available in the 1940s.

bradknowles 3y ago
It's called a Time Domain Reflectometer. They're pretty cheap. For RG-58 style coax, you can get hand-held VeEX CX41 units for a few hundred dollars. I'm sure that TDRs for other types of cables shouldn't be too much more expensive.
jutrewag 3y ago
Perfect time to use a pin nailer.
- tonyarkles 3y ago
  Customers used to do this unintentionally with staples, and my boss was too cheap to buy a TDR tester for a long time
tialaramex 3y ago
However "a fast device that measures return latency on the shorted circuit" is presumably very cheap today. 20+ years ago, rewiring buildings for 1000baseT the Cisco switches (3650s maybe? 3750s? I know they had IPv6 multicast acceleration in the switch fabric because that's why we had them) would do this for any circuit on command, OK, 18 metres from here there's a fault, pace, pace, pace, I reckon it'll be up on this cable tray... yup, some fool tried to "repair" a broken Cat5 cable, we'll just rip it out, meanwhile patch to a different circuit.
- sandos 3y ago
  I believe I even had a BIOS in a PC that did this in some way.... Actually, I think it wasn't detecting faults but rather the length of cable connected.
- jmole 3y ago
  Time Domain Reflectometry - https://community.cisco.com/t5/networking-knowledge-base/how-to-use-time-domain-reflectometer-tdr/ta-p/3119327 https://community.cisco.com/t5/networking-knowledge-base/how...
cjbgkagh 3y ago
You can use binary search to find the pin. Unless two or more pins are used.
- monocasa 3y ago
  At that point it's easier just to run new line.
  - cjbgkagh 3y ago
    But you don’t know that when you start. You could assume it and never try to repaid and always replace but in WWII there were not as many options.

UncleEntity 3y ago

We used field phones all the time when I was in light infantry (82nd Airborne). Pretty much any time we were in a fixed position out would come the commo wire so as to not give our position away. They even went as far as having us string wire out to our ambush sites when we were on the Iraqi border during the first gulf war and reel it back up when we came in. Zero radio signals out there because they didn’t want them to know that a whole division plus French armor was there. Modern tech is good and all unless you have some dumb Joe that keeps erasing the codes out of the radio by turning on the truck without putting it on standby or something…never quite figured that one out.

sa46 3y ago
All the way! I was 1-505 PIR. > dumb Joe that keeps erasing the codes out of the radio by turning on the truck without putting it on standby Oh man, I have nightmares about comms. Juggling frequencies while traversing areas of operation, trying to get satcom working in mountainous terrain with jammers, and depending on the finicky windows-tablet encryption device, was not a fun time.