Abstract: This paper introduces the related technology of subway automatic ticket vending machine software when writing Banknote Acceptor Machine device driver, including state pattern which is one of design patterns and complemented by thread synchronization technology for Windows. Combining, the above two kinds of technology to realize the industrial computer and Banknote Acceptor Machine BU interaction and communication, the methods have a certain reference value for the programming of compliance with RS-232 device driver.

Key words: automatic ticket vending machine, device driver, state pattern, thread synchronization