Solved - Ethernet kit LED won't flash on T4.1

[bicycleguy]

This is posted as a FYI for those who may encounter it.

If the ethernet kit cable is plugged in backwards ethernet still works(somehow) but the led on the ethernet jack does not function. Apparently this upside-down connection for a few hours didn't wreck anything in my case. YRMV.

 

[TeensyWolf]

This is posted as a FYI for those who may encounter it.

If the ethernet kit cable is plugged in backwards ethernet still works(somehow) but the led on the ethernet jack does not function. Apparently this upside-down connection for a few hours didn't wreck anything in my case. YRMV.

The phy has auto-MDIX, which will auto detect a crossover cable and swap the signals.

When you plug it in backwards, it will auto correct, but LED won’t work.

 

[bicycleguy]

Thanks for that info !

 

[PaulStoffregen]

Yeah, it usually can work plugged in backwards because Auto-MDIX automatically figures out whether the RX & TX pairs are swapped, and also because the LED when not conducting has enough capacitance between its anode & cathode.