有关 SerialPort 的两点疑问，求解答！
项目中需要利用短信猫发短信，于是用 SerialPort 封装所需的AT指令，但现在遇到两点问题：
1、如果不将属性SerialPort.RtsEnable的值设为true, 则 DataReceived 事件不会发生，是否是设备原因？
2、将 SerialPort.RtsEnable的值设为true时，DataReceived 事件中接收到的数据中会包含先前写入的AT指令，例如写入"AT+CSCA?"数据后，接收到的数据则是 AT+CSCA?\n\r\n+CSCA: "+8613010112500",145\r\n\r\nOK\r\n。这是什么原因呢？
对串口操作不熟悉，求解答，多谢！！

C# code

public class Sms    {        SerialPort port;        TimeSpan waitTime;        EventWaitHandle eventWait;        public Sms(string portName, int baudRate)        {            this.port = new SerialPort(portName, baudRate, Parity.None, 8, StopBits.One);            this.port.RtsEnable = true;             this.port.ReceivedBytesThreshold = 1;            this.port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived);            this.waitTime = TimeSpan.FromMinutes(1);            this.eventWait = new EventWaitHandle(false, EventResetMode.AutoReset);        }        public bool IsOpen        {            get            {                return this.port.IsOpen;            }        }        public bool Open()        {            this.port.Open();            return true;        }        public void Close()        {            this.port.Close();        }        public string GetCenterNumber()        {            var response = this.ExecAtCommand(@"AT+CSCA?");            var number = string.Empty;            if (!string.IsNullOrEmpty(response))            {                var reg = new System.Text.RegularExpressions.Regex("\\+86[0-9]{10,13}");                var mt = reg.Match(response);                if (mt.Success)                {                    number = mt.Value.Substring(1);                }            }            return number;        }        public string ExecAtCommand(string commandText)        {            if (this.port.IsOpen)            {                this.port.DiscardOutBuffer();                this.port.DiscardInBuffer();                this.port.WriteLine(commandText);                this.eventWait.WaitOne(waitTime);                Thread.Sleep(500);                var response = this.port.ReadExisting();                              return response;            }            else            {                return string.Empty;            }        }        void port_DataReceived(object sender, SerialDataReceivedEventArgs e)        {            if (this.port.BytesToRead > 0)            {                Thread.Sleep(500);                this.eventWait.Set();            }        }    }

[解决办法]
参考

http://blog.sina.com.cn/s/blog_6017fba00100dyd1.html

http://www.eefocus.com/sxl630828191/blog/2012-02/235722_e9cf3.html
[解决办法]
默认开了回显,你执行1次关闭回显AT命令就行了,如
AT0