Specifies the current state of the Ring Indicator (RI) input signal. The RI signal is often used by modems to indicate that the telephone line is ringing. This property is read only except when the Wire Mode property is set to RS232/DCE or to RS232/Auto with the hardware currently in the DCE state.

注释

下表列出了该属性的特性。

短名称 RI State
数据类型 ci16.png
权限 读取/写入
可用于运行引擎 是
可用于实时操作系统 是
Unknown -1
Unasserted 0
Asserted 1