并行通信和串行通信是CPU与外部设备之间进行信息交换的基本方法。采用并行通信时，构成一个字符或数据的各位同时传送，每一位都占用一条通信线，另外还需要联络以保证和外围设备协调地工作，它具有较高的传输速度。但由于在长线上驱动和接收信号较困难，驱动和接收电路较复杂，因此并行通信的传输距离受到限制，这种通信方式多用于计算机内部，或者作为计算机与近距离外围设备传输信息用。-Parallel and serial communication is communication between the CPU and the external equipment to carry out the basic method of information exchange. Parallel communication to form a character or data you send, every occupier of a communication line, also need to contact to ensure coordination and peripherals to work, it has a higher transmission speed. However, due to the long-term drive and receive the signal more difficult to drive and receive circuits more complex, so the transmission distance parallel communication is limited, this means of communication used for the computer itself, or as a close-up computer and peripheral equipment used to transmit information.