Fiber Optic Foul-up



  • I along with several other technicians assisted our network engineer one Saturday with the move of a communications closet from a much too small room, across the hall to a much larger, properly air-conditioned room.  There were hundreds of Cat-5 Cables connections, a few routers, and one bundle of fiber optic cables to move. 

    Several hours into the project, with everything going as planned we had just moved the the fiber optic bundle into the new closet when one of the technicians said "Uh oh.  I broke one of the fibers."  "Not to worry", said the engineer, "Just go back to the office and bring back the fusion splicer."  "Uh...", replied the technician, "I think this fiber is the one that controls the building entry control system..."  Silence overcame us all for a quite a spell.

     You see, we had recently installed a state of the art entry control system in our three seperate buildings.  All were controlled from our workcenter (where the fusion splicer was) and a fiber optic ring went to each building to control the door entry systems.  We only had swipe badges for entry, all keys had been taken away. 

    Since it was a Saturday no one was in the office to let us into the building.  So, just break a window and climb into the office you say.  Well, you have to understand that our workcenter was located in a fall out shelter on a military installation and the command post was also located in this building so breaking in really wasn't possible.

    Finally one of the guys had a bright idea "Hey, we can just use the entry phone for the command postand someone will come up a let us in!".  Great idea we thought until two of us went over, got on the phone and found that only 1 person was in the command post, a very young airman, and he wasn't permitted to leave his post!

    It took us nearly an hour of badgering the young man to convince him that if he didn't leave his post for just a few minutes to let us in, that NO ONE was going to be able to get into the building if the was an emergency that required the use of the command post!  His commander would not be pleased if he needed to use the command post!

    We ultimately did get into the building, retrieved our fuser splicer and got the problem fixed.  I beleive our engineer put several back up fibers into place after this to keep this evil type of thing from every happening again!

     



  • This is exactly why you need a manual backup system, such as leaving the keyed system in place and having an emergency contact in case the system failed. You see it all the time in the industrial world, when some type of autonomous equipment fails, without some kind of override, everything halts.



  • So, I'm confused. The building entry controls aren't actually inside of the building it's controlling? This sounds a little strange.



  • @Volmarias said:

    So, I'm confused. The building entry controls aren't actually inside of the building it's controlling? This sounds a little strange.

    They follow the Empire philosophy of putting the shield generators outside of the shield they generate.



  • Airmen: "Hold on a sec, I'm getting out to you guys, then we can see what I can do for you..."



  • @pitchingchris said:

    This is exactly why you need a manual backup system, such as leaving the keyed system in place and having an emergency contact in case the system failed. You see it all the time in the industrial world, when some type of autonomous equipment fails, without some kind of override, everything halts.

    Or indeed, there's an emergency and the system fails, resulting in death. Honestly, it should be a legal requirement that all automated entry/exit systems have a manual override that failsafes to open. Plus that lets you do movie style pumping of big levers :-)



  • @Kemp said:

    @pitchingchris said:

    This is exactly why you need a manual backup system, such as leaving the keyed system in place and having an emergency contact in case the system failed. You see it all the time in the industrial world, when some type of autonomous equipment fails, without some kind of override, everything halts.

    Or indeed, there's an emergency and the system fails, resulting in death. Honestly, it should be a legal requirement that all automated entry/exit systems have a manual override that failsafes to open. Plus that lets you do movie style pumping of big levers :-)

    Not to mention the movie-style shutting off the power and breaking into a suddenly insecure building!



  • @rbowes said:

    @Kemp said:
    @pitchingchris said:

    This is exactly why you need a manual backup system, such as leaving the keyed system in place and having an emergency contact in case the system failed. You see it all the time in the industrial world, when some type of autonomous equipment fails, without some kind of override, everything halts.

    Or indeed, there's an emergency and the system fails, resulting in death. Honestly, it should be a legal requirement that all automated entry/exit systems have a manual override that failsafes to open. Plus that lets you do movie style pumping of big levers :-)

    Not to mention the movie-style shutting off the power and breaking into a suddenly insecure building!

    There's no reason it has to be openable from the outside - firefighters have axes for that. Or you could always give them a magic key like for elevators.



  • Let's see if I got this right.  There's a critical system that is neither duplicated nor has a backup.  And has many distributed and exposed points of failure.  Hmmm.

    You're using the most sophisticated communication system ever invented, involving microelectronics, quantum optics, and with physical, logical, and protocol layer over layer, capable of full-duplex 500 MBPS communications...   all to send maybe one bit per second.   


     Compare your getup to the way public fire alarm boxes  used to work, if not still work.  A mechanical wind-up  morse code sender, sending out dots and dashes over a single copper wire serial loop.  
     

     



  • @rbowes said:

    @Kemp said:
    @pitchingchris said:

    This is exactly why you need a manual backup system, such as leaving the keyed system in place and having an emergency contact in case the system failed. You see it all the time in the industrial world, when some type of autonomous equipment fails, without some kind of override, everything halts.

    Or indeed, there's an emergency and the system fails, resulting in death. Honestly, it should be a legal requirement that all automated entry/exit systems have a manual override that failsafes to open. Plus that lets you do movie style pumping of big levers :-)

    Not to mention the movie-style shutting off the power and breaking into a suddenly insecure building!

    If they've got the money to automate everything then they've got the money for backup generators, I'm talking more the case of control equipment failure. And if they have a fully automated system which doesn't failsafe to a safe condition (it's why it's called a failsafe) and/or which has no backup power supply... well you might want to think about working somewhere else.



  • I believe the original poster said they couldn't get IN, not they couldn't get OUT. . . Just sayin....



  • @morgano said:

    Several hours into the project, with everything going as planned we had just moved the the fiber optic bundle into the new closet when one of the technicians said "Uh oh.  I broke one of the fibers."  "Not to worry", said the engineer, "Just go back to the office and bring back the fusion splicer."  "Uh...", replied the technician, "I think this fiber is the one that controls the building entry control system..."  Silence overcame us all for a quite a spell.

    ...

     You see, we had recently installed a state of the art entry control system in our three seperate buildings.  All were controlled from our workcenter (where the fusion splicer was) and a fiber optic ring went to each building to control the door entry systems.  We only had swipe badges for entry, all keys had been taken away. 

    Okay, maybe I'm missing something here, but I thought that the whole point of a ring network is that a single break doesn't disconnect the nodes. Otherwise, why even bother running all the extra fiber? For that matter, why use a fiber-optic network for this application rather than a more-durable, slower-speed copper network. How fast do your doors need to open, anyway?



  • @mbessey said:

    For that matter, why use a fiber-optic network for this application rather than a more-durable, slower-speed copper network.

    Fibre is actually more reliable, when properly protected inside metal conduits and cable trays where some muppet can't snap the cable. Copper is highly susceptible to electrical and magnetic fields, and has issues related to ground potential when moving between buildings. Fibre is effectively immune to everything except physical damage, which is more easily defended against. 


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