Why does Nova create multiple serial devices?


#1

I am trying to write scripts to control the modem directly. I find it interesting that the device creates multiple serial endpoints. Why is this happening? Should there not be only one? What is the significance for each?

[    9.303705] usb 1-1.4: Product: u-blox Wireless Module
[    9.303713] usb 1-1.4: Manufacturer: u-blox
[    9.303721] usb 1-1.4: SerialNumber: XXXXXXXXXX
[    9.354903] cdc_acm 1-1.4:1.0: ttyACM0: USB ACM device
[    9.359121] cdc_acm 1-1.4:1.2: ttyACM1: USB ACM device
[    9.363315] cdc_acm 1-1.4:1.4: ttyACM2: USB ACM device
[    9.367777] cdc_acm 1-1.4:1.6: ttyACM3: USB ACM device
[    9.372508] cdc_acm 1-1.4:1.8: ttyACM4: USB ACM device
[    9.377185] cdc_acm 1-1.4:1.10: ttyACM5: USB ACM device
[    9.382646] cdc_acm 1-1.4:1.12: ttyACM6: USB ACM device
[   10.135986] Bluetooth: Core ver 2.22

#2

That’s totally normal and a feature of the ublox module on the Nova that we expose. It allows for things like having an open PPP session on one serial port while being able to execute AT commands for things like SMS or signal strength on the other.
Not all of the ports are usable but in the default mode you should have at least two ports able to accept AT commands.


#3

Understood! thanks!


#4

I realize your on some *nix machine but for reference the enumerated ports on Windows are:

USB\VID_1546&PID_1102&MI_06\6&1D8D6E49&0&0006 : USB Serial Device (USB Com) u-blox Modem USB4 GPS
USB\VID_1546&PID_1102&MI_02\6&1D8D6E49&0&0002 : USB Serial Device (USB Com) u-blox Modem USB2 AT and Data
USB\VID_1546&PID_1102&MI_0A\6&1D8D6E49&0&000A : USB Serial Device (USB Com) u-blox Modem USB6 Secondary Log
USB\VID_1546&PID_1102&MI_08\6&1D8D6E49&0&0008 : USB Serial Device (USB Com) u-blox Modem USB5 Primary Log
USB\VID_1546&PID_1102&MI_04\6&1D8D6E49&0&0004 : USB Serial Device (USB Com) u-blox Modem USB3 AT and Data
USB\VID_1546&PID_1102&MI_0C\6&1D8D6E49&0&000C : USB Serial Device** (USB Com) u-blox Modem USB7 SAP**
USB\VID_1546&PID_1102\357520072315613 : USB Composite Device
USB\VID_1546&PID_1102&MI_00\6&1D8D6E49&0&0000 : USB Serial Device (Modem) u-blox Modem USB1 AT and Data

I think the device instance &000* probably maps to what you see so
cdc_acm 1-1.4:1.6: ttyACM6: USB ACM device = u-blox Modem USB4 GPS


#5

Awesome! So on windows ublox is nice enough to differentiate the functionality. On Linux (Ubuntu) is there any command to probe and get the same thing?


#6

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