Hello,
If you’re using 4G, connect to the first 2 ports from the left. If you’re using 5G, use the outside ports.
Here’s a visual guide to the ports and the frequencies they accept: Which antenna to use with a RUTX50? - #9 by tirkiz
However, I highly recommend using 4x4 MIMO antennas because they can be utilized for both 5G and 4G, significantly improving data transfer rates and connection stability.
Best regards,