Relay ports 3.5 midi 3.5 difference?

Hi, I have read the manual but it is not clear to me the following, what is the difference between the 3.5 midi in and out 3.5 that are on the side and the 3.5 relay ports that are on the back…

I want to connect my fractal fm3 to the DIN 5 and use the fractal integration, as I did with the mc6, but I want to be able to control a beat buddy and a 1440 EHX looper, I couldn’t do this before because the fm3 when using the fractal integration you don’t have to put the midi THRU.

So I would like to use some 3.5 output to send the messages to the beatbuddy - EHX from there. I plan to buy a BOSS midi trs 3.5 - DIN 5 male cable to make the connection.

My doubt is which 3.5 port of the MC6 pro to use, the one on the side or the one on the back.

Do you have any other suggestions?

You’d want the Midi Out 3.5. The Relay ports would be for something like amp channel switching or a pedal that has switch jack.