本文介绍了移动通信系统中一种实用的DID和DOD接口电路。该接口电路运用单片微机技术进行接口电路的控制，利用双音频编／解码电路、语音集成电路等实现二／四线变换、语音提示、双音频信号的收发。通过DID和DOD接口电路可实现移动通信系统中无线与有线之间话音和数据通信的自动接续。 This article describes a practical DID and DOD interface circuits in mobile communication systems. The interface circuit uses single-chip microcomputer technology for the control of the interface circuit, the use of dual-audio encoder / decoder circuit, voice integrated circuits to achieve two / four line conversion, voice prompts, dual audio signals transceiver. Through DID and DOD interface circuit can be achieved in the mobile communication system between wireless and wired voice and data communication between the automatic connection.