我试图开发一个C#应用程序，将能够发送短信只通过GSM调制解调器。当我们连接GSM调制解调器到我们的笔记本电脑/PC，然后我们必须检查该调制解调器的端口从设备管理器〉调制解调器〉端口。但在这种情况下，我想连接我的Android手机作为GSM调制解调器与我的笔记本电脑，并试图使用我连接移动的的端口号，但它不是作为连接调制解调器。请帮助我，如果你有任何想法或任何可能性，连接到笔记本电脑作为GSM调制解调器的Android手机。这是我的模式。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using TextmagicRest;
using TextmagicRest.Model;
using System.Net;
using System.Collections.Specialized;
using System.IO;
using System.IO.Ports;
using System.Threading;

namespace SMS_Sending_App_2
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        try
        {

            SerialPort sp = new SerialPort();
            sp.PortName = textBox3.Text;
            sp.Open();

            sp.WriteLine("AT" + Environment.NewLine);
            Thread.Sleep(100);
            sp.WriteLine("AT+CMGF=1" + Environment.NewLine);
            Thread.Sleep(100);
            sp.WriteLine("AT+CSCS=\"GSM\"" + Environment.NewLine);
            Thread.Sleep(100);
            sp.WriteLine("AT+CMGS=\"" + textBox1.Text + "\"" + Environment.NewLine);
            Thread.Sleep(100);

            sp.Write(new byte[] { 26 }, 0, 1);
            Thread.Sleep(100);
            var response = sp.ReadExisting();

            if (response.Contains("ERROR"))
            {
                MessageBox.Show("SMS failed!", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }

            else
                MessageBox.Show("SMS Sent!!!", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);

            sp.Close();
        }

        catch(Exception ex)
        {
            MessageBox.Show(ex.Message);
        }


    }

    private void textBox1_TextChanged(object sender, EventArgs e)
    {

    }

    private void textBox3_TextChanged(object sender, EventArgs e)
    {

    }
   }
  }