The paper firstly gives a simple states of several microprocessor parallel interface modes, then introduces bidirectional parallel port ( PS / 2 ), enhanced parallel port ( EPP ) and extended parallel port ( ECP ) in practical application in detail. 在简述了微机并行口的几种模式的基础上,着重从逻辑界面、连接和时序图三方面讨论了双向并行口(PS/2)、增强型并口(EPP)和扩展并行口(ECP)。