Send SMS using GSM Modem in ASP.NET

Is it possible to send SMS messages using GSM Modem. As I try to do this I cant seem to send SMS. It always run failed. Iam using GSM Comm library.

Here is my Connect to Modem code

        if(ComPort.Text == "")
        {
            return;
        }
        comm = new GsmCommMain(ComPort.Text, 9600, 150);
        bool retry;
        do
        {
            retry = false;
            try
            {
                comm.Open();
                string message = "Success!";
                System.Text.StringBuilder sb = new System.Text.StringBuilder();
                sb.Append("<script type = 'text/javascript'>");
                sb.Append("window.onload = function(){");
                sb.Append("alert('");
                sb.Append(message);
                sb.Append("')};");
                sb.Append("</script>");

                ClientScript.RegisterStartupScript(this.GetType(), "alert", sb.ToString());
                retry = true;
            }
            catch (Exception)
            {

                string message = "Gsm not available";
                System.Text.StringBuilder sb = new System.Text.StringBuilder();
                sb.Append("<script type = 'text/javascript'>");
                sb.Append("window.onload = function(){");
                sb.Append("alert('");
                sb.Append(message);
                sb.Append("')};");
                sb.Append("</script>");

                ClientScript.RegisterStartupScript(this.GetType(), "alert", sb.ToString());
                return;
            }
        } while (retry);
    }

And here is my Sending code

 protected void Send_Click(object sender, EventArgs e)
    {
        try
        {
            SmsSubmitPdu pdu;
            pdu = new SmsSubmitPdu(Message.Text, Number.Text);
            comm.SendMessage(pdu);

        }
        catch
        {
            string message = "Sending failed!";
            System.Text.StringBuilder sb = new System.Text.StringBuilder();
            sb.Append("<script type = 'text/javascript'>");
            sb.Append("window.onload = function(){");
            sb.Append("alert('");
            sb.Append(message);
            sb.Append("')};");
            sb.Append("</script>");

            ClientScript.RegisterStartupScript(this.GetType(), "alert", sb.ToString());
        }
    }

I dont know what the problem is. But it cant send messages. Thank you for the help. Thanks