Call and Play wav file using usb modem c#

Question

I have written a code to dial a number using USB modem connected and want to play a .wav file on the serial port connected.

My code is making the call but when I try to transfer voice using AT command it always through the exception some time "Access denied on port."(but if able to call why access denied) and some time "Device not connected"(but call is on going. How do I reconnect my device while call is going on.)

Below is the code I am using, please take a look.

public static void MakeCall(string number, string filepath, string PORT = "COM3")
    {
        SerialPort serialPort = new SerialPort();
        serialPort.PortName = PORT;
        serialPort.BaudRate = 9600;
        serialPort.Parity = Parity.None;
        serialPort.DataBits = 8;
        serialPort.StopBits = StopBits.One;
        serialPort.Handshake = Handshake.RequestToSend;
        serialPort.DtrEnable = true;
        serialPort.RtsEnable = true;
        serialPort.NewLine = System.Environment.NewLine;
        serialPort.Open();
        Console.WriteLine("OPEN");
        if (serialPort.IsOpen)
        {
            Console.WriteLine("OPENED");
            serialPort.WriteLine(@"AT" + (char)(13));
            Thread.Sleep(200);
            //serialPort.WriteLine("AT+CMGF=1" + (char)(13));
            Thread.Sleep(200);
            serialPort.WriteLine(@"ATD" + number + ";\r");
            Thread.Sleep(30000);
            serialPort.Write("AT+VTX" + System.Convert.ToChar(13).ToString());
            bool MSwitch = false;
            byte[] buffer = new byte[20000];
            FileStream strm = new FileStream(filepath, System.IO.FileMode.Open);
            MemoryStream ms = new MemoryStream();
            int count = ms.Read(buffer, 44, buffer.Length - 44);
            BinaryReader rdr = new BinaryReader(strm);
            while (!MSwitch)
            {
                byte[] bt = new byte[1024];
                bt = rdr.ReadBytes(1024);
                if (bt.Length == 0)
                {
                    MSwitch = true;
                    break;
                }
                //This line through exception but not in first loop iteration but after few iterations
                serialPort.Write(bt, 0, bt.Length);
            }
        }
    }

I have the same issue. – Umair Rasheed Feb 07 '20 at 18:44 — Umair Rasheed, Feb 07 '20 at 18:44

score 0 · Answer 1 · answered Mar 13 '23 at 02:23

0

GSM modem have 2 ports , 1 for comment , 1 for voice , select voice port again .

answered Mar 13 '23 at 02:23

dnhat

1

Thanks for your answer! Can you please provide a code snip of how you would do this given the example? I think that would be very helpful :) – Impurity Mar 18 '23 at 13:35
Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Mar 18 '23 at 13:35

Call and Play wav file using usb modem c#

1 Answers1