Does marlin not work with cncjs, even though there is an option for marlin?
this is what I get when connected.
reading up on it, it does seem cncjs was originally meant for grbl, but marlin was added later.
I use cncjs with my SKR Pro / Marlin LR2. I really enjoy using it, I’ve set up a lot of macros and buttons that work for me. I’ve not tried any other web interfaces so I don’t know if I’m missing out on something better, but I’m happy.
That screenshot looks like the classic indication that your serial parameters are not set correctly. Most likely you have the wrong bit rate, but other settings could be wrong as well.
It depends on how Marlin was configured. I don’t use Mini Rambo, but most of the Marlin systems use 250000. I’ve seen them at different rates, so if that doesn’t work for you we should look to see what the settings are in the firmware you used on the board.
You send an M503 and get an unknown command?
There’s still something wrong with the com settings, then…
Can you paste a screenshot of exactly what it looks like as you try M503 or M119 ?