[PLUG-TALK] Cat5e cable: open [UPDATE]

Galen Seitz galens at seitzassoc.com
Sun Dec 29 10:53:06 PST 2019

On 12/29/19 10:25 AM, Rich Shepard wrote:
> On Sun, 29 Dec 2019, Rich Shepard wrote:
>> Is there a test for cable integrity? I've installed RJ-45 plugs on cat5e
>> cables before this and each has passed the tester. Before I waste more 
>> plugs
>> should I consider the entire cable compromised and build a new one?
> I just put plugs on a new cable of the same length as the 'open' cable.
> Passed the integrity test. So I guess the old cable has a broken wire
> somewhere and would like to know if there's a way to determine where it is.

Just perform a binary search.

1. Cut cable in half.
2. Test each half.
3. Set good half aside.
4. Go to step 1 with bad half.

You could probably find the location of the open with a time domain 
reflectometer (TDR), but a new cable will be cheaper by about 3 orders 
of magnitude.

Galen Seitz
galens at seitzassoc.com

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