This is not standard on cash registers since the customer is using the display to view the subtotal so it doesn't matter because the receipt is given after the sale. It can usually be turned on in the settings tables in programming. It will probably be labelled something like "print subtotal on receipt" in the programming section of your manual. I haven't worked with a 500dx so I can't be more specific unless you have a scanned or e version of the manual.
Registerman, August 2013
