What does "3" refer to in the E3317-A01 x16 PCIe Tx/Rx swap module


I am working on designing my own pcb for x16 PCIe Tx/Rx swap.

I found that there are two places denoted with “3”. Previously, I thought it was the only used for ‘WAKE’ and ‘PERS’. Then I found it is also used in RX/TX area as shown below. Not sure what does it mean.

Zoomed in version:


That’s number of page of schematic, you can ignore that.

Also please file questions of E3317 in same one topic.

Thanks for the reply and the suggestion. I will do it later.