PRO DJ LINK with 1x CDJ-900 - Is a switch necessary, or 1x LAN cable works?

Hi Forum,

Seeking help with using the Pro DJ Link feature on one of my CDJ-900s. I've explored the topic and seen guides on how to combine two CDJ-900s via a switch and then into Rekordbox. However, I would only like to use the Pro DJ Link feature with ONE CDJ-900, not BOTH.

Tried connecting with a LAN cable between the CDJ directly to computer with Rekordbox. No "LINK" alternatives show up in Rekordbox as I've seen in several videos. However, the small red square in the bottom left corner of the CDJ (stating its Player 1) starts flashing rapidly for a few seconds as if it would be connecting. But no results in terms of being able to drop songs into the CDJ over the connection in Rekordbox.

Is it an explicit criterion that one needs to use a network/LAN switch for this to work? Even if I want to use only one CDJ as described?

Appreciate any info. Thanks