I am in need of a converter that converts USB to RS232 signal levels. I want to replace an older Serial touchscreen on my CNC machine with a newer one that is USB. I cannot install a driver on the controller. IS there anything out there that could be used?
The most direct component we have is a USB to RS232 converter cable: https://www.sparkfun.com/products/11304
The problem is going to be that there isn’t a USB host. When a USB device is connected to another, there’s a bit of discussion between the two. They agree on things like data rates, device addressing, and the device class (are you a mass storage device, a printer, a keyboard, sound card, etc?). The CNC controller has a serial input so it can’t serve as the host. The touch panel also can’t be the host; it’s a display and human interface device. I’m not aware of an aftermarket interface or adapter that could make these work together.
If the new screen USB interface is merely a USB serial connection (i.e. like a FTDI converter) then you may be able to use an Arduino with built-in USB serial to do the conversion between the two. If the new screen USB interface is a low-level USB device (i.e. HID) then perhaps using something like an RPi in between the screen and the CNC should work.