Public Function txt2pdu(ByVal stxt As String) As String
For Y = 1 To Len(stxt)
        X = Dec2Bin(Asc(Mid(stxt, Y, 1)))
        'If X = "100000" Then X = "0100000"
        Text = X & Text
        Next Y
    'Debug.Print Text
    l = Len(Text)
    s = l - 7
    out = Bin2Hex(Mid(Text, s, 8))
    Do Until s <= 8
    s = s - 8
    out = out & Bin2Hex(Mid(Text, s, 8))
    Loop
    out = out & Bin2Hex(Mid(Text, 1, s - 1))
    'Debug.Print out
    
    X = Hex(Len(stxt))
    If Len(X) = 1 Then
            X = "0" & X
        End If
    'Debug.Print X & out
    txt2pdu = X & out
End Function
Public Function Dec2Bin(ByVal nDec As Integer) As String
    'This function is the same then Hex2Bin,
    '     but it has been copied to speed up proce
    '     ss
    Dim i As Integer
    Dim j As Integer
    Dim sHex As String
    Const HexChar As String = "0123456789ABCDEF"
    
    sHex = Hex(nDec) 'That the only part that is different


    For i = 1 To Len(sHex)
        nDec = InStr(1, HexChar, Mid(sHex, i, 1)) - 1


        For j = 3 To 0 Step -1
            Dec2Bin = Dec2Bin & nDec \ 2 ^ j
            nDec = nDec Mod 2 ^ j
        Next j
    Next i
    'Remove the first unused 0
    i = InStr(1, Dec2Bin, "1")
    If i <> 0 Then Dec2Bin = Mid(Dec2Bin, i)
    If Len(Dec2Bin) = 6 Then Dec2Bin = "0" & Dec2Bin
End Function
Public Function Bin2Hex(ByVal sBin As String) As String
    Dim i As Integer
    Dim nDec As Long
    sBin = String(4 - Len(sBin) Mod 4, "0") & sBin 'Add zero to complete Byte


    For i = 1 To Len(sBin)
        nDec = nDec + CInt(Mid(sBin, Len(sBin) - i + 1, 1)) * 2 ^ (i - 1)
    Next i
    Bin2Hex = Hex(nDec)
    If Len(Bin2Hex) Mod 2 = 1 Then Bin2Hex = "0" & Bin2Hex
End Function