I run cable test and it report the 2nd pairs is open
But I don't know the 2nd pairs's color ?
I use T568B for my cable

Thank you

I run cable test and it report the 2nd pairs is open
But I don't know the 2nd pairs's color ?

It's listed in the TIA-568-B specification document.

Here is the table from page 7:

Here's a nice visual color guide for cat5 cables -
http://www.duxcw.com/digest/Howto/netwo ... cable5.htm

Here's a nice visual color guide for cat5 cables -
http://www.duxcw.com/digest/Howto/netwo ... cable5.htm

I would not recommend this site as it only specifies the cross-wired pattern used for 100BASE-T wiring. This deprecated crosswiring pattern will cause devices that don't implement MDI/MDI-X to fail to connect. While most 1000Base-T devices support MDI/MDI-X it is not mandated in the standard. For 1000BASE-T, Both sets of pairs MUST be crossed.

Always get your information straight from the standards documents, or a reliable vendor specification.

The correct pinout for a 1000BASE-T crossover cable: Source:
http://www.cisco.com/c/en/us/support/do ... .html#appb

I run cable test and it report the 2nd pairs is open
But I don't know the 2nd pairs's color ?

It's listed in the TIA-568-B specification document.

Here is the table from page 7:

colour codes.png

The problem with this table is it doesn't identify the pin to colour code of the ethernet connectors where the Duxcw site does. See the problem is the pair number is the same for each colour in 568A and 568B. The pair numbers are not wired to the same pins though on the different standards.