目前，串口是常用的计算机与外部控制系统之间的数据传输通道。使用串行通信，在实时性、速度、数据量等方面受到限制。计算机的并行端口传输数据速度要比串口快，在许多必须讲究传输速度的控制系统里，用PC并行端口与之连接就是一个很好的解决方案-Currently, serial data transfer path between the common computer with an external control system. Using serial communications, limited in real-time, speed, amount of data and so on. Parallel port data transfer speed of the computer s serial port faster than in many must pay attention to the transmission speed control system with PC parallel port connected to it is a good solution