A custom ethernet cable with both connectors wired as T568B only works when connecting A to B, but not reversed, i.e. when switching ends and connecting B to A.
A is a Mac, B is a 1Gb TP-Link unmanaged switch. Tried with different Macs and switches. “Works” means both devices see each other (the LED in the switch's ethernet port lights up, and on the Mac's System Preferences > Network, “ethernet” has a green dot) and the Mac can connect to the rest of the network.
What might the reason be?