reading problem from serial port(use serialport class)
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in my C# program(I mainliy use SerialPort class),I input "at" in a textBox,then the program send "at" to serial port(the other end of serial port is a modem which is connected to my computer by a data line),but when i click receive button,the message I receive from serial port is the same as what I input,namely "at",not "ok",why?who can answer my question?How I solve this problem and get the right response "ok" from serial port? next is my code: public partial class Form1 : Form { private SerialPort sp = null; public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { try { sp = new SerialPort("COM1"); sp.ReadTimeout = 5000; sp.Open(); } catch (Exception ex) { MessageBox.Show(ex.Message); } } private void button2_Click(object sender, EventArgs e) { try { sp.Write(textBox1.Text); } catch (Exception ex) { MessageBox.Show(ex.Message); } } private void button3_Click(object sender, EventArgs e) { try { /*string text=null; char[] buffer = new char[10]; sp.Read(buffer,0,6); for (int i = 0; i < buffer.Length; i++) { text += buffer[i]; } textBox2.Text = text;*/ /*string text = null; char t = (char)sp.ReadChar(); text+=t.ToString(); while (true) { t = (char)sp.ReadChar(); if (t == '\0') break; else text += t.ToString(); } textBox2.Text = text;*/ string text = null; byte[] t = new byte[20]; char[] c = new char[20]; sp.Read(t, 0, t.Length); sp.Read(t, 0, t.Length); c = Encoding.ASCII.GetChars(t); int i; for (i = 0; i < c.Length; i++) { if (c[i] == 'O' || c[i] == 'K') text += c[i].ToString(); } textBox2.Text = text; } catch (Exception ex) { MessageBox.Show(ex.Message); } } }
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in my C# program(I mainliy use SerialPort class),I input "at" in a textBox,then the program send "at" to serial port(the other end of serial port is a modem which is connected to my computer by a data line),but when i click receive button,the message I receive from serial port is the same as what I input,namely "at",not "ok",why?who can answer my question?How I solve this problem and get the right response "ok" from serial port? next is my code: public partial class Form1 : Form { private SerialPort sp = null; public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { try { sp = new SerialPort("COM1"); sp.ReadTimeout = 5000; sp.Open(); } catch (Exception ex) { MessageBox.Show(ex.Message); } } private void button2_Click(object sender, EventArgs e) { try { sp.Write(textBox1.Text); } catch (Exception ex) { MessageBox.Show(ex.Message); } } private void button3_Click(object sender, EventArgs e) { try { /*string text=null; char[] buffer = new char[10]; sp.Read(buffer,0,6); for (int i = 0; i < buffer.Length; i++) { text += buffer[i]; } textBox2.Text = text;*/ /*string text = null; char t = (char)sp.ReadChar(); text+=t.ToString(); while (true) { t = (char)sp.ReadChar(); if (t == '\0') break; else text += t.ToString(); } textBox2.Text = text;*/ string text = null; byte[] t = new byte[20]; char[] c = new char[20]; sp.Read(t, 0, t.Length); sp.Read(t, 0, t.Length); c = Encoding.ASCII.GetChars(t); int i; for (i = 0; i < c.Length; i++) { if (c[i] == 'O' || c[i] == 'K') text += c[i].ToString(); } textBox2.Text = text; } catch (Exception ex) { MessageBox.Show(ex.Message); } } }
This may have nothing to do with your code. Modems have an Echo mode, returning exactly what you send to them. This sounds like your problem. Configure the modem to turn echo mode off, "ATE0" if I recall correctly, in the modem initialization. Of course, the "ATE0" may be returned/echoed the first time, but then everything should operate as expected. You may want to save the configuration after you have done this. Gary