I'm testing a Tinker board, which is an ARM gadget running Debian 9.8. I inserted a USB modem. It appears the modem was detected but I can't find a device for it:

[ 8178.815663] usb 1-1.1.5: new full-speed USB device number 11 using dwc2
[ 8179.245691] usb 1-1.1.5: New USB device found, idVendor=0572, idProduct=1300
[ 8179.245712] usb 1-1.1.5: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 8179.245726] usb 1-1.1.5: Product: USB HSF Modem
[ 8179.245738] usb 1-1.1.5: Manufacturer: Conexant Systems, Inc.


$ ls /dev/*ACM*
ls: cannot access '/dev/*ACM*': No such file or directory
$ ls /dev/*USB*
ls: cannot access '/dev/*USB*': No such file or directory

Debian has a wiki page at HowToIdentifyADevice | USB but I can't really tell what I need to do. On Fedora I open /dev/ACM0 or /dev/USB0, depending on the modem being used.

How can I determine the device assigned to the the USB modem?

The answers I have found are in the context of a hard drive, like Useful Ways to Know Plugged USB Device Name in Linux and How to determine which sd* is usb?. Obviously a modem is not assigned a hard disk name.

Here's a similar question for RPI's, but it shows the modem being assigned a /dev/USBn device, which is not happening for this modem: No IP for USB 3G modem Huawei E3131 using modemmanager


# lsusb
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 011: ID 0572:1300 Conexant Systems (Rockwell), Inc. SoftK56 Data Fax Voice CARP
Bus 001 Device 009: ID 046d:c05a Logitech, Inc. M90/M100 Optical Mouse
Bus 001 Device 007: ID 1c4f:0002 SiGma Micro Keyboard TRACER Gamma Ivory
Bus 001 Device 005: ID 2101:8501 ActionStar
Bus 001 Device 003: ID 2101:8500 ActionStar
Bus 001 Device 002: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 002: ID 0bda:481a Realtek Semiconductor Corp.
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  • 2
    linuxant.com/drivers/hsf/index.php . It appears it's a soft modem requiring processing by the CPU. This looks really outdated so I'd be surprised this can work on modern kernels. Here are people who tried: github.com/george-hopkins/hsfmodem/issues/1 . Buy an other modem – A.B Mar 16 '19 at 22:17
  • Is it reported by nmcli d? [Does NetworkManager see it via ModemManager?] – AnFi Mar 16 '19 at 22:37
  • Thanks guys. How do I find the device associated with the USB modem? – user56041 Mar 16 '19 at 23:25

You could try creating the nodes and then see if a serial comms. program can communicate, e.g.

mknod /dev/usb/ttyACM0 c 166 0


mknod /dev/ttyACM0 c 166 0

See: http://www.linux-usb.org/USB-guide/x332.html

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