The Control box is really something...:
* The Emergency-Stop button is a complete joke. After one usage, it literally fell apart. It would anyway not comply with CE rules for an emergency button.
* The separate 5V cabling for the parallel-port card is also a joke. Just adding a little 5V power supply would have been so easy, and could surely have been bought in china for a very small amount of money...or even integrated into the parallel-card.
* The designer of the parallel-card should get an award for ignorance!
They used 74HC chips on the card. This means the card will not work for modern PC parallel ports (for they all have an output level of 3.3V). These 3.3V are within the parallel port specification, because it was defined as 5V-TTL-levels. But they used pure CMOS Chips, which do not interpret 3.3V as high. They should instead have used 74HCT chips. These are TTL-Level compatible and interpret 3.3V as high. I think I gonna resolder some 74HCT types on the board.