Sub Test_dajüm()
    Dim InputFile As String
    Dim lBuffer As Long
    Dim sBuffer As String
    Dim sMuster As String
    Dim lTreffer As Long
    Dim sTreffer As String
    Dim lBeginn As Long
    Dim lEnde As Long
    sMuster = "mi(101,"
    InputFile = "D:\DeinInputFile.txt"
    Open InputFile For Binary As #1
    lBuffer = FileLen(InputFile)
    sBuffer = Space(lBuffer)
    Get #1, , sBuffer
    sBuffer = Replace(sBuffer, Chr(13), "")
    sBuffer = Replace(sBuffer, Chr(10), "")
    lBuffer = Len(sBuffer)
    Do While lTreffer <= lBuffer
        lTreffer = InStr(lTreffer + 1, sBuffer, sMuster)
        If lTreffer = 0 Then
            Exit Do
        Else
            lBeginn = InStr(lTreffer, sBuffer, ",")
            lEnde = InStr(lBeginn + 1, sBuffer, ",")
            sTreffer = Mid$(sBuffer, lBeginn + 1, lEnde - lBeginn - 1)
            MsgBox sTreffer, vbInformation, "Die fortlaufende Nummer lautet:"
        End If
    Loop
    Close #1
End Sub