摘要
现有的调制解调器（ＭＯＤＥＭ），没有由电话振铃启动工作电源的功能；当它自动应答的是通话呼叫时，无本机振铃唤人和给对方等待提示的功能，这使得将其应用于工业控制系统的自动数据通信等场合时颇不方便．为此，设计了一种“ＭＯＤＥＭ自动应答功能扩展器”，它具有“任务唤醒”功能和自动应答通话任务时的唤人回应处理功能，能够启动本地振铃声唤人接电话，并给对方发送等待信号．文章介绍了ＭＯＤＥＭ的自动应答功能、自动电源控制电路的设计以及振铃唤人和回话处理电路的设计。
The present MODEM product has not the functions such as starting its operational power by call and can not ring to warn and send waiting voice to the other party while answering automatically ic a voice call, so it is not ideal for use in industrial control system for automatic data communication. To solve this problem, a kind of MODEM expander with automatic responding features is designed,which do have the functions such as'woken by call'and'ring to warn and send waiting voice to the other party while answering automatically to a voice call'.This paper introduces the designs of automatic MODEM responding function and automatic power control circuits as well as the designs of ringing to warn and answering function circuits
