I have some cheap rj45 tester and wanted to test my newly installed rj45 cord. And because the most of cord is underfloor (there is some risk this was damages during renovation) I wanted to make sure how to interpret this double blink.
Damage or for some reason - I am not good at manual jobs - I connected the ending wrong.
So far I researched it is T-568B:
This is the female wall rj45: