eithernet cable oddity

[kylebisme]

i just bought a 100' of ethernet cable and put some connecters on but it won't support a connection. i tested all each of the pins and found them all to be well connected with 2.3 ohms of resistance for each of the eight wires for a straight though connection which i think is respectable for such a long cable, but my router just fashes at me when i plug it in. anyone have any ideas on what could be wrong?

 

[JackMDS]

Testing CAT5 Cable.

In very general terms, testing CAT5e cables for Home LAN usage can be done by:

1. Measuring DC continuity.

2. Using RF signal.

3. Commercially Certifying the Cable.

The 1st method is basically useless since DC continuity can be OK, yet the Cable will be very poor RF conduit. (The cable has to deal with a 100Mb/sec. signal).

To employ the 2nd method.

For about $50-$100 you can find a Tester that is constructed of two units.

One unit is placed at one end and inject RF signal to the Cable, the second unit receives the signal (or not).

Cables tested by this method are fairly safe to use at home.

The 3rd option involved very expensive hardware made by Fluke Co. (Entry Level Pro Fluke is $600). However it is the way the pro goes.

More here: Wiring - I would like to wire my Networked Computers (Home Wiring).

 

[kylebisme]

so most likely radeoshack just sold me bad cable eh?

 

[gunrunnerjohn]

My guess is you don't have the twisted pairs connected properly. Even though you can read continuity end to end, that doesn't mean that you have a working cable. I wish I had a nickel for every time I've had to cut the connectors off and rewire them after the "professionals" wired a building!

For long runs that are difficult to string, I test the cable with a TDR before stringing it, and again before putting it into service. Don't man-handle the cable, as the solid cable used for long runs is pretty fragile.

FWIW, you should only have 30 feet or so of stranded cable between devices for 100mhz operation.

 

[kylebisme]

i am not sure what you mean by " twisted pairs connected properly"; if you are talking about having the stripe and soild ones of each color next to eachother orange though brown, ya that is the way i have the connectors attached. as for the wire itself, it is solid copper and hasn't been manhandled as it is fresh off the role, you can find more info on it right here.


i actually wound up swaping the role i was useing out for a new one thinking i must have simply gotten a bad one but this new one is givng me the same results. i did wind up lopping off a few feet of the old cable and putting another end on it which worked just fine, but as for the long length i need neither the last role or this new one is giveng me a working connection. i don't rightly want to spend anything on testing tools as i don't do much network wireing, i just want my xbox in the liveingroom connected to my router in the office. should i just assume the cable radioshack is selling cannot support such a distance and try and get my money back so i can get different stuff somewhere else, or is there something i might be overlooking which i should try to get the stuff i have to work?

 

[gunrunnerjohn]

Nope, if you have all the pairs adjacent to each other, you have the cable wired incorrectly! Check this CAT5 wiring diagram for the correct wiring of the pairs.

 

[Snuffaluffaguss]

YEap, sounds to me like you didn't wire the pairs correctly. Check out the above diagram.

 

[kylebisme]

doh, sure enough, thank you for the help all.