From the control panel, see the printer you have attached to the USB port. Right click and open the properties. Open the ports tab. You will probably see a list of ports, one of which will point to the device you are interested in using (For example LPT1, COM1,...DOT4_001 etc).
You can use the device name (DOT4... for USB) to send the file. If print command does not work, simply type abc.txt > DOT4_001 , etc.
Good luck