Troubleshooting a 100' CAT5 cable - need assistance
Apr 24, 2005 29 Replies
M
Mark Evans
Why do you want to do this?
With this length of untwisted cable about the only thing you could do with the link is put one (four it you didn't mind the crosstalk issues) telephone line down it.
You really can't expect it to work if you don't use the correct cable.
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J
James Knott
Phone crosstalk??? In such a short cable??? Your phone line, back to the CO, is run for a far greater distance, without noticeable crosstalk.
M
Mark Evans
Where does the third piece of wire come from.
The crimps are intended for telephone circuits. They are not suitable for LAN cables.
The "activity" may be the speed auto-negotiation. You'd be lucky to get even 10M down a cable in such a state.
It's 100 metres with solid core cable.
If it's coiled on a desk why do you need to bodge another metre or so onto it?
If you really have to join the cable use either a CAT-5 junction box, trailing female RJ-45 or RJ-45 coupler.
M
Mark Evans
You don't really want to use soild core in such an application. The crimp connectors are unlikely to work reliably if you treat it as flex.
This would be a good place to start, solder the cat5 directly to the 8 way plug and socket. Be careful not to untwist the pairs any more than you need to.
L
lawrence.jones
Yes, but it's twisted pair.
-Larry Jones
Oh yeah? You just wait! -- Calvin
J
James Knott
The flat "satin" cable used for phones isn't twisted either, nor is that "quad" stuff that was standard for phone installations for many years. I don't see that 3 feet of untwisted cable will cause crosstalk.
M
Mark Evans
Telephone cable is still UTP. The only exception is some single pair cables.
J
James Knott
He was referring to crosstalk in a 3 foot piece on untwisted cable. However, for many years, premise phone wiring was done with untwisted pair cables. Even on today's modular phone, the flat satin wire is not twisted. Cables going back to the CO is twisted pair, but not as tightly twisted as cat 3 or 5.
L
lawrence.jones
Those aren't run "back to the CO", either. Satin isn't used for any significant distance because it does have significant crosstalk problems. Quad, on the other hand, doesn't have much immunity from external noise since it's not twisted, but it has excellent immunity from crosstalk because the molded jacket holds the pairs such that the signals induced in one pair by the other exactly cancel each other.
-Larry Jones
OK, what's the NEXT amendment say? I know it's in here someplace. -- Calvin
E
Ed Nielsen
I had a 25' satin cord for awhile on which I ran 2 lines. Crosstalk up the ying-yang. And that was when the phone at the end of the cord was on line 1 and the phone at another outlet was on the line 2. Finally, I got un-lazy enough to run a real outlet where it was needed to get rid of that satin. Problem, of course, went away.
CIAO!
Ed N.
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