How SMS Farsi (Arabic) with a GSM modem, I upload C #

<pre lang="cs">using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO.Ports;
using System.Threading;
namespace sms_at_command
{
    public partial class Form1 : Form
    {
        SerialPort myport = new SerialPort();
        string DeviceName = "";
        public Form1()
        {
            InitializeComponent();
            //تنظیمات پورت
            myport.BaudRate = 9600;
            myport.Parity = Parity.None;
            myport.StopBits = StopBits.One;
            myport.DataBits = 8;
            myport.ReadBufferSize = 10000;
            myport.ReadTimeout = 1000;
            myport.WriteBufferSize = 10000;
            myport.WriteTimeout = 10000;
            myport.RtsEnable = true;
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            cmbPortName.SelectedIndex = 0;
        }
        private void button1_Click(object sender, EventArgs e)
        {
            if (cmbPortName.Text.Trim() != "")
            {
                try
                {
                    lblDeviceName.Text = "";
                    myport.PortName = cmbPortName.Text.Trim();
                    if (!myport.IsOpen)
                        myport.Open();
                    myport.DiscardOutBuffer();//خالی کردن بافر
                    myport.WriteLine("AT+cgmm\r");//دستور شناخت مدل دستگاه
                    Thread.Sleep(500);
                    DeviceName = myport.ReadExisting();
                    if (DeviceName.Contains("ERROR"))
                        MessageBox.Show("Device does not support this command or any other problem...");
                    else
                    {
                        //دستورات زیر برای بیرون کشیدن نام دستگاه از رشته خوانده شده از پورت هست
                        //(char)13   کاراکتر اینتر!
                        DeviceName = DeviceName.Remove(0, DeviceName.IndexOf((char)13)).Trim();
                        DeviceName = DeviceName.Substring(0, DeviceName.IndexOf((char)13));
                        MessageBox.Show("detected successfully" + Environment.NewLine + "Device Name:" + Environment.NewLine + DeviceName, "", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        lblDeviceName.Text ="Device Name: "+ DeviceName;
                        btnSend.Enabled = true;
                    }
                    myport.DiscardOutBuffer();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
                finally
                {
                    myport.Close();
                }
            }
        }
        private void cmbPortName_SelectedIndexChanged(object sender, EventArgs e)
        {
            btnSend.Enabled = false;
        }
        private void btnSend_Click(object sender, EventArgs e)
        {
            if (txtTel.Text.Trim() != "")
            {
                try
                {
                    if (!myport.IsOpen)
                        myport.Open();
                    //خالی کردن بافر
                    myport.DiscardOutBuffer();
                    myport.DiscardInBuffer();
                    //قراردادن دستگاه در حالت متنی
                    myport.WriteLine("AT+CMGF=1\r");
                    //دستور ارسال اس ام اس
                    myport.WriteLine("AT+CMGS=\""+txtTel.Text.Trim()+"\"\r");
                    myport.WriteLine(txtMessage.Text.Trim() + '\x001a');// \x001a  (برای انتهای پیام ctrl+z معادل)
                    Thread.Sleep(500);
                    if (myport.ReadExisting().Contains("ERROR"))
                        MessageBox.Show("Device does not support this command or any other problem...");
                    else
                    {
                        MessageBox.Show("Sent successfully", "", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }
                    myport.DiscardOutBuffer();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
                finally
                {
                    myport.Close();
                }
            }
            else
            {
                MessageBox.Show("Enter Tel");
                txtTel.Focus();
            }
        }
        private void button1_Click_1(object sender, EventArgs e)
        {
            help f = new help();
            f.ShowDialog();
            f.Dispose();
        }
    }
}