The DS1410D Parallel Port Button Holder interfaces Dallas Semiconductor Authorization Buttons to host computers via a PC parallel port. In conjunction with the Buttons, the DS1410D provides a high security storage vault for critical execution control information. Only users that possess a Button can utilize the software, preventing execution of unauthorized copies. The modularity of the DS1410D allows for easy feature customization. The device supports the insertion of two Buttons, which can be removed and replaced to vary functionality.