how to receive data from a hardware device through serial port.

[Nazmeen]

hii
am able to send hex data to the hardware device but not able to receive the data it is sending here is my code

Public Function getMessage() As Integer
        Try
            Dim hostEntry As IPHostEntry = Nothing
            Dim s As Socket = Nothing


            Dim i As Integer
            Dim str, str1 As String
            str = String.Empty
            'serialport.Open()

            If ServerConnection = True Then
                While True
                    If ServerConnection = True Then
                        str1 = String.Empty

                        
                        Dim byteToRead As Byte = serialport.ReadByte()
                        Buffer.Add(byteToRead)

                        If Buffer.Count < 7 Then
                            'If Buffer.Count < 7 And Buffer.Item(0) = &H1 And Buffer.Item(2) = &H4 And Buffer.Item(3) = &H50 And Buffer.Item(4) = &H0 And Buffer.Item(5) = &H10 And Buffer.Item(7) = &HFF Then
                            receivesuccess = True

                            For iInside As Integer = 0 To 7
                                str = Hex(Buffer.Item(iInside))
                                If str.Length = 1 Then
                                    str = "0" + str
                                End If
                                str1 += str + "  "
                            Next
                            RR.Insert(0, str1)
                            'End If

                        End If
                    End If
                End While

            End If
End Function

this is send message in hex format and this is working and it is writing data to the serial port and am able to display it.

Public Function SendMessage(ByVal NoOfData As Integer) As Integer
        Try
            serialport.Close()
            serialport.Open()
            'serialport.PortName = "COM3"

            If serialport.IsOpen Then
                serialport.Write(MassageToSend, 0, NoOfData)
                'serialport.Read(ReceivedResponse, 0, 24)
                Dim str, str1 As String

                str = ""
                For ctr As Byte = 0 To CByte(NoOfData - 1)
                    str1 = Hex(ServerComm.MassageToSend(ctr))
                    If str1.Length = 1 Then
                        str1 = "" + "0" + str1 + ""
                    End If
                    str = str + Space(7) & str1 + ""

                Next

                str = ">>" + str
                Threading.Thread.Sleep(100)
                'str = System.Text.Encoding.Default(str + vbCrLf)
                With SunRose.tbText
                    .Font = New Font("Garamond", 12.0!, FontStyle.Regular)
                    SunRose.Tx.FillColor = Color.White
                    SunRose.Tx.FillColor = Color.Red
                    .SelectionColor = Color.Red
                    .AppendText(str & vbCrLf)
                    .ScrollToCaret()


                    Dim file As String = Application.StartupPath() + "\Backup\Excel\" + "HEXdata" + System.DateTime.Now.ToString("dd" & "MM" & "" & "yyyy") + ".csv"

                    Dim str_send = ""

                    str_send += str + " - " + System.DateTime.Now.ToString("dd") + "/" + System.DateTime.Now.ToString("MM") + "/" + System.DateTime.Now.ToString("yyyy") + "  " + System.DateTime.Now.ToString("HH") + ":" + System.DateTime.Now.ToString("mm") + ":" + System.DateTime.Now.ToString("ss") + vbCrLf

                End With
                Threading.Thread.Sleep(800)
end sub

but in getmessage() as soon as debuger is executing readbyte() it is not moving and nothing is geting displayed so plz help me with code and sugestions