On Wed, Sep 23, 2009 at 6:32 PM, Sean Martin <seanmarti...@gmail.com> wrote: >> Can't you just shine a light through one end and see if theres light on >> the other end? ;-) > > Does it actually work?
That will tell you if the cable has been completely snapped, e.g., kinked hard, pinched in a door, etc. It won't tell you the condition of the tip. The tips can get scratched, especially if they're put in a pile without a cable condoms on the end. A scratched tip could still pass visible light but not be good for data. The tools I've seen used for this are a power meter (already described) and a handheld microscope. The scope is basically just a flashlight and a special fitting to hold the fiber. You peak in the end and examine the tip. A clean tip looks like a solid white circle. A scratched or damaged tip has lines or other black/gray marks. > ... sharp bends in fiber can > cause problems because those light impulses can end up being reflected out > of order ... I can't confirm or deny that. The two cautions on bends I've heard are: (1) Fiber is glass. A sharp enough bend will snap the fiber in half. After that it's dead. (2) The more you bend it without breaking, the more of the light energy will be absorbed by the wall instead of propagating down the fiber. Eventually the loss (either in one spot, or cumulatively) goes too high and the receiver can't "see" the signal. This can at least be fixed by straightening the line. > Are my concerns valid? Is there a reasonably priced device to verify the > integrity of a fiber cable, or am I just going to have to try the flash > light trick and then plug n pray? Google suggests power meters can be had for under $300. I have no idea what a good one costs. :) -- Ben ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
