Reading Real time data thru RS232 port!!

I will use VB and a control mscomm32.ocx to implement your solution.  Since, I don't know the protocol of your device, I guess it just return some characters with control bits.

The mscomm32 object provides an OnComm event to handle all the signal transfer between PC and an input device.  As you see from the codes below, I will read the incoming signal into a buffer and scan through the buffer to remove all the unwanted control signal (you should refer to your hardware manual to find out what are they), then print it on a textbox for realtime monitoring and at the same time write it to a record file.

The codes follows:


Public PrepareLog as Boolean

Private Static Sub MSComm1_OnComm()
    Dim SignalString$  
    Select Case MSComm1.CommEvent
        ' Event messages.
        Case comEvReceive
            Dim buffer As Variant
            buffer = MSComm1.Input
           
         ' Eliminate transferring signal from screen.
            SignalString$ = Chr$(8) & Chr$(32) & Chr$(8)  'the unwnated control signal of the device
            For i = 1 To Len(buffer)
                If i = InStr(buffer, SignalString$) Then
                    buffer = Left$(buffer, i - 1) & Mid$(buffer, i + 3)
                End If
            Next
 
         'provide onscreen realtime signal respond on a textbox "txtTerminal"    
           txtTerminal.Text = txtTerminal.Text & buffer
           txtTerminal.SelStart = Len(txtTerminal.Text)

        'write the file to record the process
        PrintLog buffer, filelognum

           txtTerminal.SelStart = Len(txtTerminal.Text)
    End Select
End Sub

Public Sub PrintLog(PrintString As String, FileNo As Integer)
    If PrepareLog = False Then Form_Initialize
    Dim length As Long
    length = LOF(filenum)
    Put #FileNo, length + 1, PrintString
End Sub

Private Sub Form_Initialize()
start = Now
PrepareLog = True
    filelognum = FreeFile
    OpenLog
        PrintLog "This file record down all the comm-port activities that carried out by the host.", filelognum
        PrintLog "Written by Antony Leung.", filelognum
        PrintLog "********************************************************************************", filelognum
        PrintLog "Application:" + App.EXEName + ".exe", filelognum
        PrintLog "Working path:" + App.Path, filelognum
        PrintLog "Login Time:" + Format(start), filelognum
        PrintLog "", filelognum
End Sub

Public Sub OpenLog()
    Open App.Path & "\filename.extension" For Binary As #filelognum 'your record file goes here
End Sub