Testing a Cash Drawer that is connected to the receipt printer 1) Make sure that the cable that goes from the cash drawer is connected to the printer. 2) Make sure your printer is plugged into the appropriate port on your computer. 3) Go to the MS-DOS prompt. 4) If your printer is connected to LPT1, then type: copy con lpt1: 5) Then press CTRL-G and hit the enter key 6) Then press CTRL-Z and hit the enter key. Your drawer should pop open.