مشکل در ارسال اس ام اس !

[ak1_2004]

مشکلش کجاست ؟

SerialPort1.PortName = "COM92"

SerialPort1.Open()

SerialPort1.WriteLine("AT" & vbCrLf)

SerialPort1.WriteLine("AT+CMGF=1" & vbCrLf)

SerialPort1.WriteLine("AT+CSCA=""+9891100500""" & vbCrLf)

SerialPort1.WriteLine("AT+CMGS=" & "09171255391" & vbCrLf)

SerialPort1.WriteLine("> test" & vbCrLf & Chr(26))

SerialPort1.ReadLine()

RichTextBox1.Text = SerialPort1.ReadExisting

SerialPort1.Close()