Magnetics part with and without auto-transformer

[FreshmanNewbie]

I have 2 magnetics part.

One magnetics is this & the other magnetics is this

When I use the Halo part, the ethernet link is not up. But when I just replace the Halo part with the Pulse electronics part, the link is up without any issues.

Then, I found that the Pulse magnetics part has an auto-transformer portion inside it.

My question is, is the auto-transformer portion helping with the ethernet linking-up? Or, it might be because of some other issue with the PCB?

 

[FvM]

No idea what you mean with "autotransformer", I don't see this feature. Both transformers have center tap and additional common mode chokes. You didn't tell the exact Halo and Pulse types used.

More important to know PHY interface circuit. It should be possible to determine if Rx, TX or both are falling.

 

[FreshmanNewbie]

No idea what you mean with "autotransformer", I don't see this feature. Both transformers have center tap and additional common mode chokes. You didn't tell the exact Halo and Pulse types used.

More important to know PHY interface circuit. It should be possible to determine if Rx, TX or both are falling.

yes sorry. Can you please explain what you mean by "Rx, Tx or both are falling"?

 

[FvM]

Sorry autocorrection typo, I meaned failing.

--- Updated Sep 12, 2023 ---

Different ethernet magnetics have slightly different parameters although they fulfill the general specification. Ethernet interface is very robust, I guess that your circuit has a serious issue, e.g. a broken line, but is still partly operating.

 

[BradtheRad]

I'm reminded of my attempt to join ethernet cables using an inexpensive 8 wire telephone-style connector. It was a simple straight-thru connector that seemed like it should work. However I could not get two computers to recognize each other over the longer distance. I didn't understand why.

I found I had to use the special connector specifically designed to transmit ethernet. At first sight it looks exactly like the cheap telephone connector. I've never opened it up but I've seen diagrams that show ethernet wires need to be joined by a certain kind of tiny transformers and/or inductors.