[geeks] [rescue] Cable testers

[Josh Snyder]

On 4/20/2016 1:50 PM, Lyle Bickley wrote:
> On Wed, 20 Apr 2016 13:19:41 -0400
> Phil Stracchino <phils at caerllewys.net> wrote:
>
>> Anyone have a preference for good but not overly expensive Ethernet
>> cable testers?  I don't want to spend $500 on a high-end Fluke, but I
>> don't want to spend $10 on some generic piece of crap that only tests
>> continuity either.  I've never really needed one until now, but I'm
>> finding cat6 to be a complete &@&#$@^#@%$R@#% to strip and terminate.
> Here's the one I use. It not only checks out RJ-45 (CAT 6), but also
> all classically needed cables (RS-232, etc.).
>
> http://www.amazon.com/CableWholesales-Cable-Tester-Tests-IEEE-1394/dp/B000I993ZQ

That sure looks to me to just be a continuity tester.  Granted, it's 
nice and has tons of cable types that are supported.  But if Phil is 
really looking something more than a continuity test I don't think that 
will do what he needs.

I have recently had the "fun" of dealing with a small number of cat6a 
runs.  The total length was about 70 meters.  We had nothing but 
problems.  First cat6a cable is weird.  It's hard to describe it's 
nothing like cat5e or even "normal" cat6; it reminds me of rubber tubing 
from my high school chemistry class.  You can take a cable out of spec 
by bending it too much.  For short runs even at 10Gbit we didn't have 
problems.  But once we were going longer than 30 meters it felt like 
anything wrong would pull the cable path out of spec.

We had to bring in a real tester in because none of the long runs would 
link up at 10Gbit without constant CRC errors.  We found that ALL of the 
patch panels we bought initially were not actually in spec with cat6a.  
We had to purchase costly patch panels to terminate the links.  We also 
had to re-run two of the cables as someone had put a small kink in the 
cable during installation.  Even after working the kinks out of the 
cables one of them was still not in spec and it would not work reliably 
at 10Gbit.

In the end we ended up using fluke DSX-5000 to do the testing.  We 
rented it for the installation.  I don't know what the total cost would 
have been to purchase what we were using.  But I do know it was way more 
than $500.  It was the only way we were able to get the links going and 
be sure they should keep working.

             Josh