I am trying to connect to an Airmar 200WX and not having much luck finding the /dev mount point of the sensor.

I have the sensor plugged in on boot and dmesg displays the following:

[    1.150836] udevd[99]: starting version 175
[    1.157625] usb 1-1: new full-speed USB device number 2 using musb-hdrc
[    1.276745] usb 1-1: ep0 maxpacket = 8
[    1.277966] usb 1-1: default language 0x0409
[    1.284552] usb 1-1: udev 2, busnum 1, minor = 1
[    1.284575] usb 1-1: New USB device found, idVendor=0403, idProduct=cc60
[    1.284587] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[    1.284598] usb 1-1: Product: AIRMAR USB<=>RS485 SerialConverter
[    1.284608] usb 1-1: Manufacturer: FTDI
[    1.284618] usb 1-1: SerialNumber: FTXGZX9O
[    1.285085] usb 1-1: usb_probe_device
[    1.285103] usb 1-1: configuration #1 chosen from 1 choice
[    1.285220] usb 1-1: adding 1-1:1.0 (config #1, interface 0)
[    1.290343] hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002
[    1.290390] hub 1-0:1.0: port 1 enable change, status 00000103

So it looks like it is connected. I have read elsewhere that dmesg should display a mount point. It clearly does not and I have tried all the obvious serial connections (/dev/ttyUSB0, /dev/ttyUSB1, /dev/ttyAMA0, /dev/ttyAMA1).

I can also see the device under lsusb:

Bus 001 Device 002: ID 0403:cc60 Future Technology Devices International, Ltd 

Not dismayed by this, I tried writing a udev rule in the hopes it would capture the device as it is connected and mount it for me.


SUBSYSTEM=="tty", ATTRS{idVendor}=="0403",ATTRS{idProduct}=="cc60", ATTRS{serial}=="FTXGZX9O", SYMLINK+="airmar"
SUBSYSTEM=="tty", ATTRS{idVendor}=="0403",ATTRS{idProduct}=="cc60", ATTRS{serial}=="FTXGZX9O", MOD="0666", GROUP="ttyusb"

But this did not work either.

I then tried to see if I could use udevadm info -q all to identify more parameters for the device, but I could not find an obvious match in tree /sys/bus/.

I also don't know if there is anything I should do to prepare the Raspberry Pi for this type of serial connection.

Any help would be greatly appreciated!

  • You haven't tried ls /dev with it unplugged and then ls /dev with it plugged in and then comparing the two outputs...? – Patrick Cook Apr 13 '16 at 5:24
  • I feel like there should be a better way to go about it, but yeah, I have. There's no difference. – James Taylor Apr 13 '16 at 5:25
  • Basically my question boils down to: what other steps can I take if the device shows up in dmesg, but isn't mounted properly? – James Taylor Apr 13 '16 at 13:33
  • Do you know that your device is Linux compatible? That’s a weather station multi sensor. In general when you plug a new device into a Linux computer it either is already configured for you with a driver in the default kernel or you may have to do some or a lot more work to make it compatible. – T. M. Jan 13 '19 at 10:20

I suspect the problem might be custom VID/PID assigned to the device preventing the default FTDI driver module from being associated with the device correctly. As far as I know there are two ways of telling the module about the new VID/PID (other than recompiling it):

  • Running modprobe in a udev rule to pass the extra parameters to the module: ...RUN+="/sbin/modprobe -q ftdi-sio product=0xcc60 vendor=0x0403"

  • Adding the new VID/PID to sysfs with a line like echo 0403 cc60 > /sys/bus/usb-serial/drivers/ftdi-sio/new_id. You could do this with udev as well or using a boot script or maybe using an entry in /etc/tmpfiles.d/

FTDI have a Technical Note (TN101) about the first method but I don't think it works since the driver module was updated to use the sysfs method in 2013.

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Looks like the device just exposes a USB serial port. You will need to identify which serial dev node i.e. /dev/ttyS0, /dev/ttyS1 etc. The dev nodes are likely to be there all the time regardless of the device being connected.

Here is a post about how to id an active serial port dev node in Linux https://unix.stackexchange.com/questions/125183/how-to-find-which-serial-port-is-in-use

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