This is the magnetics connection in my design. This PCB circuitry has been tested and working individually, but when I connect two or more of the same PCB hardware to an ethernet switch, the subsequent hardware would not be able get physical link over ethernet, only the first one connected would work.



I did experiment just for fun, to resolder T1 and rotate it by 180, so that the common-mode-choke is on the PHY side, and that seems to solve the problem.

However, I would like to understand what the underlying cause of this issue is. This design is based off of this TI guide https://www.ti.com/lit/an/slua469/s...27981&ref_url=https%3A%2F%2Fwww.google.com%2F, so the magnetic connection should be correct.

Any help would be greatly appreciated!

 

POE power distribution will only pass through an ethernet switch if it is intentionally made to pass power through. IF the switch does not identify itself on it's label as power passing, THEN IT IS NOT GOING TO PASS ANY POWER.