On Mac OSX Mavericks, why does Arduino Uno uses serial port named /dev/cu.usbmodemfa131 while Arduino Nano uses /dev/cu.usbserial-A702NY8S?

Are they using different FTDI drivers?

  • Which revision of the Arduino board do you have?
    – asheeshr
    Mar 25 '14 at 23:53
  • @AsheeshR Arduino Uno R3 and Sainsmart Arduino Nano v3
    – Nyxynyx
    Mar 26 '14 at 3:41
  • To throw another spanner in the works, have you ever noticed what happens to the serial port identifier when you put the Arduino Uno R3 into a different USB? For me 131 <--> 121. But if you change the Nano between ports, the identifier is the same!
    – Madivad
    Jun 12 '14 at 0:07

Drivers are different. On older boards, such as Duemilanove you may need to actually download serial drivers to talk to them at all in Lion, Mountain Lion, Mavericks. There's some discussion of that problem here.


It's really down to the manufacturer and what they identify their USB side as. I have found that Arduino(tm) provide a more meaningful (to me) identifier, eg /dev/cu.usbmodemfa131 Whilst the boards that use the FTDI chip have the more serialised numbers /dev/cu.usbserial-A702NY8S.


The Uno is not using FTDI drivers at all, since it does USB through an ATmega16u2, not an FTDI chip.

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