I know that on the wiki page you recommended some RJ45 transformers.
Let’s take, for example, the first one, from Cetus, J1B121ZCCD.
It has the following internal schematic. Notice the beginning of the internal windings.
We are using the following transformer from Amphenol: LMJ1998824110DL1T39J.
Also notice the beginning of the internal windings.
The Amphenol RJ45 transformer works, but notice, that even if the TX section is on the same pin numbers (1, 2 and 3), the beginning of the windings, on your recommended transformer is on pin 1 and on our transformer is on pin3.
Question is: being in the RF zone (100-125Mhz) is this aspect important?
Or can be used any transformer, no matter of the beginning of the windings?
Or should TX+ be kept at the beginning of the windings and TX- to the end, meaning in our case to switch W5500 TX+ and TX- on the transformer input?
I want to mention here, that for the sake of experiment, we put TX+ and TX- directly and then reversed on the RJ45 transformer input and worked either way.
But for the sake of conformity, please tell us how it’s better?