user9900: at http://www.ftdichip.com/FTDrivers.htm they seem to divide chips into two categories,  FT4222H vs. D2XX driver. 
What's the correct for a arduino nano?

user337: The Official Arduino Nano has an FTDI FT232RL.
You want to use the Virtual Com Port(VCP) Driver so the FTDI device appears as a COM port under windows.
See the getting started guide for details.

9900: <p>at <a href="http://www.ftdichip.com/FTDrivers.htm" rel="nofollow">http://www.ftdichip.com/FTDrivers.htm</a> they seem to divide chips into two categories,  FT4222H vs. D2XX driver. </p>

<p>What's the correct for a arduino nano?</p>
 337: <p>The <a href="http://www.arduino.cc/en/Main/arduinoBoardNano" rel="nofollow">Official Arduino Nano</a> has an FTDI FT232RL.</p>

<p>You want to use the <a href="http://www.ftdichip.com/Drivers/VCP.htm" rel="nofollow">Virtual Com Port(VCP) Driver</a> so the FTDI device appears as a COM port under windows.</p>

<p>See the <a href="http://www.arduino.cc/en/Guide/Windows#toc4" rel="nofollow">getting started guide</a> for details.</p>
