like for example: does the green wire mean something in a Cat6/Cat5e cable?


The Cat5e/Cat6/Cat7 cables are colored differently, because a technician for example should know how correctly set the connectors on the cable. Imagine if you have to put a connector on 30m cable, when the cords inside are with the same color?

There are also different type of cable termination, depending on what devices you're going to use (although nowadays most of the devices support Auto MDI-X).

Most common is the twisted pair cable. There are two (widely used) standards for it - TIA/EIA-568-B.1-2001 T568A Wiring and TIA/EIA-568-B.1-2001 T568B Wiring (commonly referred as A and B). They are used when you have to create a straight (twisted pair) cable. You connect pin 1,2,3,6 on side1 to pins 1,2,3,6 on side two (depending on the standard, you use orange&white, orange, green&white, green for respectively 1,2,3,6, or you start with green&white for 1 and end with orange for 6)

So, to create a crossover cable you need to connect:

Side 1
- pin 1 (green&white - it's `transmit +` signal)
- pin 2 (green - it's `transmit -` signal)
- pin 3 (orange&white - it's `receive +` signal)
- pin 6 (orange - it's `receive -` signal)

Side 2
 - pin 1 (orange&white - it's `transmit +` signal)
 - pin 2 (orange - it's `transmit -`)
 - pin 3 (green&white - `receive +`)
 - pin 6 (green - `receive -`)

You see - you can't do all this with the same color.

  • Actually, the standard calls for all four pairs to be connected for a single WAO connection. That is actually required for 1000BASE-T (1 Gbps on UTP) to connect. Also, ANSI/TIA/EIA define the cable categories, and they have refused to recognize or certify a Category-7, so there are no specifications or test suite for such a cable category. ISO/IEC does have a Class F cable that seems to be about what most people are calling Category-7. The only recognized cable categories are 3, 5e, 6, and 6a. See the latest ANSI/TIA/EIA 568 standard. – Ron Maupin Mar 28 '17 at 16:25
  • So in a 1000gb ethernet cable,do they only use 4 pins or 8 pins? – CuriousityKillsMe Mar 29 '17 at 6:05
  • 1
    1 Gbit/s cable uses four pairs, that is eight pins. There isn't a 1000gb ethernet cable yet. – Tero Kilkanen Mar 29 '17 at 6:35
  • ohh I misspelled, i meant 1000base t – CuriousityKillsMe Mar 29 '17 at 6:40

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