[X4U] Network Cables and Speed

[Robert Ameeti]

At 6:09 PM -0700, 4/8/08, Daly Jessup wrote:

>Robert Ameeti wrote:
>
>>BUT... To enable 1000BASE-T to actually happen, the cable must be 
>>wired for all 4 pairs. The problem becomes that many Cat-5 or 
>>Cat-5e cables that you pick up off the shelf will only have 2 pairs 
>>terminated as that is all that Cat-5 and Cat-5e need or use. The 
>>manufacturers do not bother to terminate the other 2 pairs all too 
>>often. The 8P8C terminators used for Cat-5 and Cat-5e are also not 
>>of sufficient quality to achieve the noise reduction that 
>>1000BASE-T would need for its speed benefits.
>
>How do you know if the cable you are buying is wired for all four?

The only proper way would be to use a cable tester. They are not 
expensive but are very handy for those that want to buy cables on the 
cheap. They will test for continuity, shorts, and the better ones 
will test for noise as well. Any qualified cable installer would have 
to properly test their installation if they are supposedly installing 
for gigabit speed as that speed has a very specific and tight 
criteria. The cable can not be stretched beyond a certain pound pull, 
can not be pulled over corners smaller than a minimum radius, etc. A 
simple ohm meter (continuity tester) can check for continuity from on 
set of contacts to the other end but you must check for more than 
just continuity so as to ensure that any single wire is not also 
crossed with another.

These links might be of interest: 
<http://www.swhowto.com/CAT5_Ch1.htm> 
<http://www.lanshack.com/cat5e-tutorial.aspx>


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Robert Ameeti

I don't care what is written about me so long as it isn't true.
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