I have a chinese 3020 machine and want to use Easel to operate. I want to use a Windows 10 laptop with a 25pin to USB adaptor
Gshield Arduino?
Unless the 3020 uses grbl as its firmware you cannot use Easel with the 3020.
If you wanted to go to the effort you might be able to replace the 3020 electronics with a grbl compatible setup.
In my experience that is one of the hardest parts about running a china machine is the electronics and software
I see lots of people just convert them over to available electronics as the other hardware will work with almost anything