<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
I've made a start.... this is flawed (at the end of step 2 we
haven't definitively identified the bundles at the far end) but
might inspire somebody. My guess is that you need to use uneven wire
counts in each bundle you can glean more information....<br>
<br>
But I'm pretty sure that the divide into three groups and wiring up
two is the correct starting point...<br>
<br>
Mike<br>
<br>
<u><b>First step</b></u> <br>
Separate the cables into 3 bundles of 40, short all cables in the
bundle together Connect each end of the battery terminals to one
bundle of 40 (leaving one bundle unconnected).<br>
<br>
<b>Walk to the other end.</b><br>
<br>
Connect light to a random wire, and try to get a circuit by
connecting to each of the other wires. If nothing lights, try
another wire.<br>
<br>
When you get a light, you will then be able to move one jumper
around to find which 39 other wires are also in that bundle. Do the
same with the other terminal of the bulb.<br>
<br>
You will then have three bundles of 40. One you will be know more
about (it's not connected at the other end) but you won't know which
bundle is connected to the positive terminal, and which is to the
negative (oh for an LED or meter).<br>
<br>
<u><b>Second step </b></u><br>
For each bundle of 40, divide it into two sets of 20, and jumper
together. Jumper two bundles of 20 from one of those connected to
one of the battery terminals together, jumper each bundle of 20 from
the unconnected pair to a bundle of 20 that is connected to the
battery.<br>
<br>
<b>Walk back to the other end</b><br>
<br>
Use the bulb in series with the battery to separate the starting end
into 6 bundles of 20. you will also be able to work out which
bundle was connected to which battery terminal, accurately
identifying both ends of the bundle.<br>
<br>
Label each cable.<br>
<br>
<u><b>Step 3</b><b> & 4</b></u><br>
Deal out the cables again 3 or 4 from each bundle of 20, into new
bundles of 40. Repeat. The above process, <b>walking another two
trips</b><br>
This will allow you to divide the cables into 36 bundles of three or
four.<br>
<br>
<u><b>Step 5 & 6</b></u><br>
Deal out the cables again bundles of 3 or for , into new bundles of
40. Repeat. The above process, <b>walking another two trips</b><br>
This will allow you to identify individual cables.<br>
<br>
<br>
On 4/09/2011 7:48 p.m., Synco Reynders wrote:
<blockquote
cite="mid:CAKNOA8JcTgUPrOt0y54wT-oFMPmKdcqqx+UXgPWbzUzOqdKFRg@mail.gmail.com"
type="cite">
<pre wrap="">As I was pulling through some wires today I remembered this classic challenge...
A 120 wire cable has been laid firmly underground between two
telephone exchanges located 1km apart.
After the cable was laid it was discovered the individual wires are
not labeled. There is no visual way of knowing which wire is which and
thus connections at either end is not immediately possible.
As trainee technician your boss has asked you to sort it out and
identify / label the wires at both ends. You only have a battery and
light bulb to test continuity and tape/pen for labeling the wires.
What is the shortest distance in kilometers you will need to walk to
correctly identify and label each wire?
</pre>
</blockquote>
<br>
</body>
</html>