This tests four combination of loopback on a board-to-board setup and those are;
•Near-End PCS loopback > LOOPBACK (001)
•Near-End PMA loopback > LOOPBACK (010)
•Far-End PMA loopback > LOOPBACK (100)
•Far-End PCS loopback > LOOPBACK (110)
This tests four combination of loopback on a board-to-board setup and those are;
•Near-End PCS loopback > LOOPBACK (001)
•Near-End PMA loopback > LOOPBACK (010)
•Far-End PMA loopback > LOOPBACK (100)
•Far-End PCS loopback > LOOPBACK (110)