说明：  自动售货机使用的货币识别装置由其它厂商生产，都支持MDB／ICP协议，而课题所研究的控制系统也参照MDB／ICP协议标准设计对应的接口，以便与它们通信。因此本课题并不涉及货币的识别技术、射频卡通信技术等领域的内容，而是研究如何通过通信协议获得货币外设返回的信息，例如顾客的投币金额，以及如何操作货币外设完成如找零、退币等功能。
(The currency identification device used in the vending machine is produced by other manufacturers, which supports the MDB / ICP protocol. The control system studied in this project also designs the corresponding interface according to the MDB / ICP protocol standard, so as to communicate with them. Therefore, this topic does not involve currency identification technology, radio frequency card communication technology and other fields, but studies how to obtain the information returned by currency peripherals through the communication protocol, such as the amount of money invested by customers, and how to operate currency peripherals to complete functions such as change and return.)