alt Hacker News> Telephones only want a twisted pair. Ethernet, popular with businesses for decades, also wants a twisted pair.
This is why there are two wiring standards, T568A and T568B, with A being compatible with multi-line telephone systems:
> The T568A scheme is based on the older USOC (Universal Service Order Code) standard, which was used for telephone wiring before the advent of high-speed data networks. The USOC standard assigned the green pair to the first line and the orange pair to the second line of a two-line phone system.
* https://www.comms-express.com/infozone/article/t568a-and-t56...
> As of 2018, ANSI/TIA still [recommended] T568A for residential installations for plug-in backward compatibility with old technology like fax machines or a plug-in base station for wireless phone handsets. If you are not using any such devices, or have no intention of plugging ancient RJ11 plugs into RJ45 wall jacks like you would a “phone jack”, then it comes back to personal preference again.
* https://www.truecable.com/blogs/cable-academy/t568a-vs-t568b
* https://www.flukenetworks.com/knowledge-base/application-or-...
As long as both ends of the cable are the same, it does not practically matter which variant is used.
* https://en.wikipedia.org/wiki/ANSI/TIA-568#Wiring
There are also A-B crossover cables (though a lot of NICs can do auto-crossover nowadays):