I possessed what is called a Time Delay Reflectometer. A TDR is an electronic device that lets you troubleshoot a length of cable. You hook it up to one end of a cable and it sends a signal down it. Since it knows the speed of light, and since you tell it what the composition of the cable is, it will tell you how long a span of cable is, whether it is passing all the energy properly, etc. It does this by counting how long it takes for a reflection to come back to it. (Energy gets reflected back down the cable when it hits an "interface" like a break in the cable or the natural end of the cable.) The TDR has a display that shows you all this information.
TDRs are a bit expensive. We did not have one at the shop where I worked, which was too bad because they can save you lots of time in troubleshooting a failed length of cable.
I remember at this one hotel, which was spread out among two dozen buildings, we had buried cable amounting to several miles' worth. Gardeners were forever digging up our cables or nicking them. When you nick a cable or perhaps introduce moisture into it, the cable will selectively not work: Some channels may be fine while others are not. Or perhaps the "channels" that carry the internet data may flake out. Wholesale cable failures are easy to spot; cable flakiness is more difficult to pinpoint.
So we had this one problem that was causing massive amounts of lost revenue because none of our technicians could pinpoint the fault in the cable. We had six guys working on the problem for a week.
My boss knew that I personally owned a TDR. I bought it as an investment in my trade. It would enable me to pinpoint the location of the fault in less than thirty seconds. We could have guys with shovels dig up that failed span of cable and re-splice it and have it fixed in an hour. My boss also knew that I would be happy to put my TDR to use to fix such a problem.
"Chris, I'd like you to come out and meet up with us to fix that outside plant problem at site fourteen nine seven seven. I need you there at eight."
As a cable man, I was never even out of bed at eight. "I'll see you there at eleven. How's that sound?"
"Yeah. ...Alright, then. ...Sounds good."
I thought it might.