Need help with a serial port on a windbox
 

Ok gentlemen, Perhaps I am as dense as a pile of bricks But I need your help.


I have a windbox https://hobbyking.com/en_us/windbox-...___store=en_us
It has ppm in ppm out

but what I can not figure out is what the heck Serial port is. it has one pin labelled as rx another labelled as tx and battery...

I know that I can connect my futaba transmitter to the ppm in and change the setting, so I can control the unit by my transmitter,
I know that the PPM out can either connect to a 433 transmitter

What the heck is the Serial port used for??
Please advise.