The board is not bad at a glace. The MFG seems to have abandoned it. UCNCV4 http://www.variometrum.com/PDF/USBCNC_csatolo_ENG.pdf produced by https://variometrum.hu/ still has for the moment the PDF file available. I have removed the metal can from the board to expose the MAIN processor. it is a pic18lf4550-i/pt with a programing port next to it. I'll post the pinouts when I get the chance. There is a secondary processor on the board with a programming port as well. stm8s903k3t6c again I'll post the programing header when I get the chance.. Different web sites seem to claim different functions. some say usbcnc control software only otheres talk about mach3 support...... I have the CD that came with it I have yet to look at it...