首先讲接线，要触发CTS等引脚的事件，必须对CTS等引脚施加一个高电平。高电平的来源可以来自第四脚，同时必须在软件中对第四脚置高电平。

C#部分代码如下

mSP.PortName = "COM1";mSP.BaudRate = 9600;mSP.DtrEnable = true;    //这里是对DTR置高电平mSP.RtsEnable = true;    //这里是对RTS置高电平mSP.Open();mSP.PinChanged += mSP_PinChanged;int mSPPinCount = 0;StringBuilder mSB = new StringBuilder();System.DateTime mDTPinLast = System.DateTime.Now;void mSP_PinChanged(object sender, System.IO.Ports.SerialPinChangedEventArgs e){if (((System.TimeSpan)(System.DateTime.Now - mDTPinLast)).TotalMilliseconds < HealthyExamination.Common.BaseC.GlobeValues.LocalParas.CaptureSerialPortPinDelayMS){return;}mDTPinLast = System.DateTime.Now;mSPPinCount++;//引脚    简写      功能说明//1       CD        载波侦测（Carrier Detect）//2       RXD       接收数据（Receive）//3       TXD       发送数据（Transmit）//4       DTR       数据终端准备（Data Terminal Ready）//5       GND       地线（Ground）//6       DSR       数据准备好（Data Set Ready）//7       RTS       请求发送（Request To Send）//8       CTS       清除发送（Clear To Send）//9       RI        振铃指示（Ring Indicator）if (e.EventType == System.IO.Ports.SerialPinChange.CtsChanged)          //引脚8{mSB.Insert(0, System.DateTime.Now.ToString("mm:ss:ffff") + "\t" + "CtsChanged mSPPinCount=" + mSPPinCount.ToString() + "\r\n");}else if (e.EventType == System.IO.Ports.SerialPinChange.CDChanged)      //引脚1?{mSB.Insert(0, System.DateTime.Now.ToString("mm:ss:ffff") + "\t" + "CDChanged mSPPinCount=" + mSPPinCount.ToString() + "\r\n");}else if (e.EventType == System.IO.Ports.SerialPinChange.DsrChanged)     //引脚6{mSB.Insert(0, System.DateTime.Now.ToString("mm:ss:ffff") + "\t" + "DsrChanged mSPPinCount=" + mSPPinCount.ToString() + "\r\n");}else if (e.EventType == System.IO.Ports.SerialPinChange.Ring)           //引脚9{mSB.Insert(0, System.DateTime.Now.ToString("mm:ss:ffff") + "\t" + "Ring mSPPinCount=" + mSPPinCount.ToString() + "\r\n");}else if (e.EventType == System.IO.Ports.SerialPinChange.Break)          //引脚{mSB.Insert(0, System.DateTime.Now.ToString("mm:ss:ffff") + "\t" + "Break mSPPinCount=" + mSPPinCount.ToString() + "\r\n");}else{mSB.Insert(0, System.DateTime.Now.ToString("mm:ss:ffff") + "\t" + "Others mSPPinCount=" + mSPPinCount.ToString() + "\r\n");}}