+Tx +Rx -Tx -Rx Connectivity
A normal patch-thru 1-to-1 cable   4-wire Tx+ to Tx+ etc , is what I would expect , not a crossover cable, Tx+ to Rx+ etc.

I believe this is the M12 D-coded 4-wire assignment, although I have never used these myself.  These should be 100BASE-Tx RS485 4-wire physical interface signal levels.