C# application to send SMS

Question

Please can anyone find the error in this code. 

Connecting to the port is OK, but the SMS doesn't send.

 

//Connecting to port

//__________________________________________________________________________________________________________________________

private void button1_Click_1(object sender, EventArgs e)

{

if (txtComPort.Text == "")

{

MessageBox.Show("Invalid port number");

return;

}

comm = new GsmCommMain(txtComPort.Text, 9600, 150);

Cursor.Current = Cursors.Default;

bool retry;

do

{

retry = false;

try{

Cursor.Current = Cursors.WaitCursor;

comm.Open();

Cursor.Current=Cursors.Default;

MessageBox.Show("Connected");

}catch(Exception)

{

Cursor.Current=Cursors.Default;

if(MessageBox.Show(this,"GSM is not available","Check",MessageBoxButtons.RetryCancel,MessageBoxIcon.Warning)==DialogResult.Retry);

}

}

while(retry);

}

//Send SMS

//__________________________________________________________________________________________________________________________

try

{

SmsSubmitPdu pdu;

byte dcs = (byte)DataCodingScheme.GeneralCoding.Alpha7BitDefault;

pdu = new SmsSubmitPdu(txtSMS.Text, txtRecoverTel.Text,dcs);

int time = 1;

for (int i = 0; i < time; i++)

{

comm.SendMessage(pdu);

}

}

catch(Exception)

{

MessageBox.Show("Not availale");

}