Ethernet link

Hi, I need some expert networking advise here. I have to connect two different PC together via a unique ethernet path. Please see attach picture. I however cannot go thru a switch or a hub.

**my setup requires using external USB to Ethernet converters on both sides of the PC.

My question for the experts is.. The two PCs can only ping successfully when I use a regular Ethernet cable (straight-thru, i believe its known as T568A). I have always thought this PC to PC Ethernet link will require a T568B crossover cable instead.

This puzzled me. Can somebody confirm this is actually indeed what it should be, and help me understand how this works?

  • 2
    If it works with a straight-through cable, it's hard to argue that that's wrong ;-p
    – Ron Trunk
    Commented Dec 6, 2017 at 15:48
  • It's working with your conventional straight through cable because one or both of your USB ethernet adapters are "Auto MDI". You lucked out. en.wikipedia.org/wiki/Medium-dependent_interface#Auto_MDI-X Commented Dec 6, 2017 at 17:36
  • Hi, if the USB-Ethernet adapter supports Auto MDI, then shouldn't both straightthru and crossover cable work?
    – Faisal
    Commented Dec 6, 2017 at 23:40

1 Answer 1


With modern equipment, you can use a straight-through or crossover cable. Most equipment can detect and configure a crossover in the interface, if needed.

You seem to be confused about the cabling standards. Both T568A and T568B are straight-through if you use the same standard on both ends. It is only a crossover if you use T568A on one end, and T568B on the other end.

  • Thanks, this is good info. Will try today if a direct PC-PC connection with straightthru works..(not via the USB-Ethernet adapter)
    – Faisal
    Commented Dec 6, 2017 at 23:41

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