Both are (USB) powered with 5V, so I doubt they work, as they may end up sending a signal with too high voltage to the HD. too high Voltage signal on RXD - TXD?.. Both converters are theoretically "3.3V to 5V Power Input."... I was thinking about use another power source (like AA batteries), not usb cable- using two aditional pins (they are labeled as gnd-+5v, but I suppose it can works with +3,3v - +5v) I am not sure about chip used, MAX232CPE - MAX232EPE... I don´t know if they works exactly as MAX232 Ukiah