difference betw ethernet cable and twisted (?) cable

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Pat

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Hi:

Some time ago there was a discussion regarding connecting two computers by cable.  I bought a long network cable that plugs into the ethernet port on each computer, only to find out that I should have bought a "twisted" cable.  I am sending both cables to someone who may be interested in connecting two computers in his house for his twins.  Could someone explain the difference between these two cables that I could include with them?  I realize he may try to network them via wifi. 

Thanks.

--pat
 

Tom

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Pat,

I suspect that the "twisted cable" you're referring to is actually a "patch cable" also known as a "crossover cable" which is required to connect two computers. This cable has a couple of wires "crossed over" so that they end up on the correct pins at the other end.
 

Karl

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Pat,

Tom is correct. When you go to buy the correct "crossover" cable, you can verify that you have the correct one this way: Hold the two plug ends side-by-side and compare the colors of the wires (visible thru the plug ends) from left to right. Two of the three colored wires will not be the same; the other three are white and don't make any difference.
 

Tom

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Karl said:
.... you can verify that you have the correct one this way:

I knew you'd come up with an easy way to tell the difference Karl. Used to be you'd look for the orange colored cable, but color "standards" seem to have gone by the wayside and I always have to readt the label when I'm at Fry's.
 

John From Detroit

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Gee. in my lexicon "Twisted Pair" means Telephone (Which is 4 wires usually) CAT-5 or 6 is 8 wires.  However depending on the plug, they plug may well fit either jack


By the way folks,  The Cat-5 Cable I had them install in my rig still won't work. And I'm sure the wires are proper now

I'll likely rip it out and re-do it myself
 

Pat

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Thanks for the clarifications on the crossover wire.  Someday I need to learn how to set up a wifi system. 

--pat
 

Ned

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Pat said:
Someday I need to learn how to set up a wifi system.

With WiFi you don't have to worry about getting yours wires crossed :)
 

Tom

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Good one Ned, I'll have to remember that  ;D
 

AlGriefer

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John In Detroit said:
...
By the way folks,? ?The Cat-5 Cable I had them install in my rig still won't work. And I'm sure the wires are proper now

I'll likely rip it out and re-do it myself

Is the Cat-5 connected to the jacks correctly?  Unfortunately, a lot of "telephone" guys don't lealize that the cable needs to be connected pin 1 to pin 1, pin 2 to pin 2, etc., rather than just ensuring that the outside wires are connect to the outside and the inside to the inside.

For telephone use, the twisted pairs could connect to either pin in the pair, for ethernet, they must connect to the specific pin.

Cat 5 refers to Category 5 twisted pair cable which was the first really good twisted pair cable for ethernet.  there are now higher category cables that work better for higher speeds or longer runs.  These cables come in either 2 pair or 4 pair; make sure you know that your adapter will work on 2 pair before buying the cheaper cables.  By the way, Cat-3 usually refers to telephone grade cables.

Crossover cables are used to connect two adapters together without an intervening hub or switch.  The have the output pair of pins on one end "crossed over" to the input pair of pins on the other end.

The modular plugs on the end are designed such that generally smaller plugs will fit in the same size or larger jacks, i.e., a 4 pin plug will fit in a six or eight pin jack.  The exception to this is that some plugs are keyed with a tab on the side that will prevent them from fitting in a normal jack.  You usually only find these for special applications such as ISDN, but I've seen them in bins right next to standard cables.

Hope this helps without being too lengthy!

Al
 

John From Detroit

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AlGriefer said:
Is the Cat-5 connected to the jacks correctly?  Unfortunately, a lot of "telephone" guys don't lealize that the cable needs to be connected pin 1 to pin 1, pin 2 to pin 2, etc., rather than just ensuring that the outside wires are connect to the outside and the inside to the inside.

Well, let me put it this way,  I have one of those cable testers, the kind that has 16 led's and two LAN type jacks, I plug both ends into the thing, turn it on, and the led's march together (Which is how they shoudl work) at DC levels the cable is perfect. It seems to be an issue at LAN frequencies only... I strongly suspect either 1: Cheap cable or 2: Some serious kinking or 3: Some inductave interference along the way (The cable does lie in a conduit with a bunch of other cables, including power (AC mains)

I'm most likely going to tear it out and re-do it with a switch in the "Basement" near where it heads up next to the power lines... If I get a good connection there. it's a good place for a switch in any case (Actually plan on putting one there) and it will narrow down the problem.  It is a low priority though

Currently I usually hook up the laptop wireless, and the box that really wants to be wired, does not yet occupy the motor home
 

Mike in Texas

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If you are connecting two Macs together, there is another option for transferring information called Target Disk Mode. The two Macs are connected with a six pin to six ping Firewire cable and the one to serve as a hard drive is shut down and then rebooted holding the "T" key down. After it starts up, it will appear as a disk drive on the other computer's desktop. When finished with the file transfer, just eject the pseudo drive by clicking on the eject button on the desktop, power that machine down, and reboot it.
 

Jeff

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John In Detroit said:
Gee. in my lexicon "Twisted Pair" means Telephone (Which is 4 wires usually) CAT-5 or 6 is 8 wires.  However depending on the plug, they plug may well fit either jack


By the way folks,  The Cat-5 Cable I had them install in my rig still won't work. And I'm sure the wires are proper now

I'll likely rip it out and re-do it myself

John:

After QZ I purchased a new HP printer with an ethernet port. Needed a ethernet cable run from an upper cabinet in the bedroom where we mounted my DW modem and Linksys router up to the cabinet I use for our printer in the front of the coach. I purchased a preassembled 50' Cat 6 cable from Frye's and ran it vertically to the basement, across the coach and forward to the front cabinet and up through the floor. I too was worried about interference as it runs parallel to other electrical cables and chassis wiring but it has worked like a charm and allows me to use the router as a switch to do wireless printing.
 

Karl

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Jeff,

I'm not at all surprised that it works for you. Allowing for any cable length restraints (which surely exceed any weird routing you may use in a MH), twisted pair as used in communications cables negate most, if not all, concerns of inductance from outside sources.

John,

I'm not sure what you're trying to connect together or what other cable runs are there that you may think are causing your problems. If you can provide more details, may be we can offer some assistance in tracking down the problem.
 
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