Cat6 100Mb/s vs 1000Mb/s

Forums › LAN (ethernet/Wifi/routers/Bluetooth) › Cat6 100Mb/s vs 1000Mb/s

DravidDavid

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#129194 6-Sep-2013 13:35

Hey guys,

Just purchased two custom made 30m cable lengths from a company. I went through testing the cables (which I'm glad I did now, as I almost didn't) and one of them always only ever connects at 100Mb/s. I've tried two different computers and three switches. All my adapters and switches are gigabit capable. I cannot replicate the issue with any other cable but this one.

The company I purchased it from say it has nothing to do with the cable, but I get the feeling that they didn't expect me to notice the difference or care anyway.

Can a cat6 cable be accidentally crimped/wired to be capable of 100Mb capacity only? Is there something else I am missing? I can't see it being anything else so far. I was afraid something like this would happen. I requested pre-made generic 30 meter length, but they made it themselves. :|

Cheers!

RunningMan

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#890898 6-Sep-2013 13:39

GigE requires all 4 pairs, 100Mb only requires 2 pairs. If one conductor on either of the extra 2 pairs was missed, swapped etc. then GigE won't work.

coffeebaron

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#890909 6-Sep-2013 13:43

Yep, my vote a miss crimped pin

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DravidDavid

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#890910 6-Sep-2013 13:43

RunningMan: GigE requires all 4 pairs, 100Mb only requires 2 pairs. If one conductor on either of the extra 2 pairs was missed, swapped etc. then GigE won't work.

In other words, it could well be the cable, and I'm being taken for a skate?

Situation has not improved. No other computer I have tested will achieve a gigabit connection.

dolsen

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#890911 6-Sep-2013 13:43

As above, yes it's possible.
Look at the wires left to right at each end, both should be the same (assume the you don't have a crossover, should be auto mdix anyway). Either they are not the same, there is an internal break in one of the wires or the end is not crimped down correctly.

RunningMan

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#890918 6-Sep-2013 13:51

DravidDavid:In other words, it could well be the cable, and I'm being taken for a skate?

A poorly made cable can most definitely exhibit the symptoms you describe.

Given the testing with various switches and computers, I'd say you have isolated to it being the cable at fault 100%.

DravidDavid

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#890932 6-Sep-2013 14:15

It is as I thought.

In the shop now. Put it on a cable tester which said it was and the guy is blaming my hardware. Refused to test it on an actual machine. Its when I said "How much money do you want to put on that cable being faulty", that he said it would be $30.00 to test it properly.

...He is currently making a new one for me as he found it as I did. I think he was expecting me to be ignorant of how it all works.

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RunningMan

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#890938 6-Sep-2013 14:23

Good outcome.

Some of the cheap cable testers just test continuity between pins. This can be correct, even if the wrong conductors in each twisted pair have been put in the wrong pins - basically, it will work for DC, but not AC at GigE frequencies.

surfisup1000

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#890986 6-Sep-2013 15:58

I reckon you're being ripped off...if one cable works ok , but not this one, then, all else being equal, the only possible conclusion is a faulty cable.

DravidDavid

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#891057 6-Sep-2013 18:45

All sorted at the end of the day. The guy didn't need to get aggressive with me when I said I wanted him to test it on a switch of his.

There was another customer in there regarding laptop issues and the tech was dishing out totally wrong information. I don't think I'll be using them any more. I don't want to call up regarding a problem and have them blame my hardware all the time!

hamish225

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#891162 7-Sep-2013 00:09

DravidDavid: All sorted at the end of the day. The guy didn't need to get aggressive with me when I said I wanted him to test it on a switch of his.

There was another customer in there regarding laptop issues and the tech was dishing out totally wrong information. I don't think I'll be using them any more. I don't want to call up regarding a problem and have them blame my hardware all the time!

ring his manager and complain

*Insert big spe*dtest result here*

nickb800

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#891199 7-Sep-2013 09:02

Name and shame?

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webwat

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#892156 9-Sep-2013 15:10

nickb800: Name and shame?

Yeah absolutely, testing the cable should be part of the original service and costs nothing. If he doesnt have a cable tester ($30 for a cheapie) then he should not have made the cable. He should also recommend you to get a permanent cable installed with a jackpoint at each end as the preferable solution where possible. Probably theres plenty of people on this forum could test the cable for you anyway.

Time to find a new industry!

nickb800

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#892162 9-Sep-2013 15:24

I actually missed the bit about them being custom cables, so yeah you would expect testing. I was also concerned by the retailers indignation and just plain wrongness

raytaylor

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#892434 9-Sep-2013 23:15

I like the ones that Ideal Electrical sell - when you test a cable, they will tell you which pairs you have mixed up.
Also have a built in tone generator.

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richms

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#892447 9-Sep-2013 23:30

Will the ideal one tell you if you have messed up the same at both ends? Its quite easy to get a couple of whites around the wrong way, and if you stuff that up the same at both ends then the cheapies will show all looking fine.

Richard rich.ms