With LEADTwain
        .Bitmap = 0
        .Visible = True
        .TwainEnumSources (.hwnd)
        For TMPInteger = 0 To (.TwainSourceCount - 1)
            If .TwainSourceList(TMPInteger) = szTwain Then   'szTwain = 
            ' Twainquelle
                .TwainSourceName = szTwain
                Exit For
            End If
        Next
 
        '- Twain Default Einstellung -
 
        .TwainRealize (.hwnd)
        .TwainMaxPages = -1
        .TwainAppAuthor = ""
        .TwainAppFamily = ""
        .TwainFrameLeft = -1
        .TwainFrameTop = -1
        .TwainFrameWidth = -1
        .TwainFrameHeight = -1
        .TwainBits = -1
        .TwainPixelType = 2                                     'TWAIN_PIX_RGB
        .TwainRes = DPI                                         'Standard = -1
        .TwainContrast = 2000                                   _
          'TWAIN_DEFAULT_CONTRAST
        .TwainIntensity = 2000                                  _
        'TWAIN_DEFAULT_INTENSITY
 
        .TwainFlags = IIf(bDialog = True, TWAIN_SHOWUI, 0)      'Twain-Dialog
 
        '- Scanner aktivieren -
 
        .ScaleMode = 3
        .AutoSetRects = True
        .AutoRepaint = False                                    'Bitmap nicht 
        ' anzeigen
        .BackColor = 12632256
        .EnableMethodErrors = False                             _
          'Fehlermeldungen unterdrücken
        .PaintSizeMode = PAINTSIZEMODE_FIT                      _
        'Vollbild/Ansicht
        .ForceRepaint                                           'Bitmap anzeigen
        nret = .TwainAcquire(.hwnd)                             'Twain Session 
        ' aktivieren
 
        '- Scan/Ende -
 
        .TwainCloseSession (.hwnd)
        IsTwainOK = IIf(nret = 0, True, False)
 
    End With

CardManager (SmartCard Tools a la CARD)