Configuring usb parallel port

I am using a PCI Parallel (//) port in my x86 linuxcnc box to handle stepping, and until now I had enough // port inputs for my needs, but I could do with more inputs where low latency is not a major issue. Whilst I could use another PCI // port card I'd prefer to save the last PCI slot for something else, so would like to use a USB // adaptor. I have a QinHeng Electronics CH340S, which I am testing.

How do I configure hal to use the USB// ?

I'm sorry to spoil this, but the USB protocol does not support real time applications. For a printer it might be enough, but not for CNC applications, because lag will occur.

Possible solutions:

• Sacrifice the last PCI slot;
• Replace existing card with a card with two LPT ports;
• MESA card;
• Or the diy-solution of using a Colorlight 5A-75E Led card (20 dollars on Aliexpress). We designed a driver for these cards. There are different variants, mine can be found be found here . With this card you get 100+ outputs, if you replace some buffers you can also get inputs.