Going to university in 1999, I had to live in an old and shoddy student’s dorm, since I couldn’t afford anything better. At least the dorm had fairly decent internet, which in my country wasn’t widespread yet back then.
But because it was forbidden to alter the building in any way, the network cables (still of the coaxial kind) were routed in a temporary fashion. They were hidden away above the ceiling tiles in the hallway and going through the door seals into the rooms, where they’d just lie on the floor. Any disconnect would result in an entire floor going offline. Being a computer science student I quickly and involuntarily became my floor's go-to person to fix those rather frequent outages, despite not having any network experience at all.
Sometimes it would be an actual ISP outage - sometimes it would be a problem with our proxy - most often though the cause was simply somebody unplugging some cable and not putting a terminator on it.
One evening the internet went out, but just for a few minutes. Then it magically fixed itself and so I thought nothing of it. But this time-limited outage repeated on the next day, and the day after it. It usually happened around 8 pm every day – not exactly, the time might vary a bit, and sometimes it might even skip a day entirely. But every time it did happen, my room-to-room phone would ring and people would get increasingly annoyed by those repeated incidents.
With each outage taking just a few minutes, I could not pinpoint the location of the interruption before things started working again. I tried running through the floor, knocking on all doors, asking if someone had unplugged anything or done anything with the cable – but I got no hints this way. I finally started to wait for the outage every day, my trusty multimeter in hand. Over the span of about a week, I managed to rule out one room after the other as the source of the interruption. Finally I found the room where resistance in the cable showed up as INF during the outage.
I knocked on the door but got no response. It was locked as well. But if nobody was in that room doing something on the computer or with the cable – how could the link possibly get interrupted? And how could it get fixed again? Next day the occurrence repeated, and again no response to me knocking on the door. I decided to unplug this room the completely, so that at least the rest of the floor had working internet.
The next morning the inhabitant of the room contacted me about his internet not working. I went into the room and measured the resistance on all the cables in there, and checked all the connections and terminators. 0 Ohms on all the cables and everything in perfect order. I asked the guy what he had been doing last evening. Just studying his books for the exams – nothing computer-related, he said. I double-checked and triple checked everything, but could not detect any problems at all.
I was almost ready to give up, when I finally noticed it: the cable was pinned underneath the bed. And sure enough, the copper lead inside the cable was broken at exactly that position – but held together by the rubber mantle firmly enough, to still have contact under normal conditions – even when I sat on the bed. But when I started rocking the bed, contact would break for a split second with every push.
It’s up to everyone’s guess what might have happened in that bed, for several minutes, every evening, at around 8 pm, with the door locked and nobody responding to knocks.