Can you simply wire a USB header with (as listd in the ASUS manual) LPx+, LPx-, and GND to pins 2, 3 and 5 respectively on a 9-pin RS232 plug? I have wide option from the AVS power buy so don't need +5.
I'd like to not route the serial cables outside the chassis to the COM ports. If I'm out in left field here, any suggestions so I can avoid routing cables outside the box? The internal USB ports are on a 4 pin connector.
USB and RS232 are two different things - no you can't do that. You could get a USB->Serial adapter and have the internal header go to that box, then connect up the screen to that (assuming the screen is a serial one and NOT usb)