# Raspberry Pi 3 B - system wide USB handling ## Persisting connected USB devices The following external hardware is connected to hangdevice ```bash #sudo mknod /dev/ttyUSB0 c 188 0 #sudo mknod /dev/ttyUSB1 c 188 1 lsusb -t #list the devices as tree lsusb -v | grep 'idVendor\|idProduct\|iProduct\|iSerial' #get some more info ```
**Device****ID Vendor:ID Product****iSerial****Product**
[![grafik.png](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/scaled-1680-/Y6enJPpWc7sHc9JW-grafik.png)](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/Y6enJPpWc7sHc9JW-grafik.png) 1d50:60ec?[OpenMoko, Inc. Duet 3D Printer Controller](https://old.stadtfabrikanten.org/display/TH/Duet+2+and+Duet+Web+Control)
[![grafik.png](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/scaled-1680-/DSJ9XQUnG2aoROz4-grafik.png)](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/DSJ9XQUnG2aoROz4-grafik.png) 046d:082dEF9B0F4F[Logitech, Inc. HD Pro Webcam C920](https://old.stadtfabrikanten.org/pages/createpage.action?spaceKey=TH&title=Webcam+C920+by+Logitech&linkCreation=true&fromPageId=62685215)
[![grafik.png](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/scaled-1680-/y5WAJ9qt75D6ILZv-grafik.png)](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/y5WAJ9qt75D6ILZv-grafik.png) 05e3:0608![(Frage)](https://old.stadtfabrikanten.org/s/-6fzg5h/9012/tu5x00/_/images/icons/emoticons/help_16.svg "(Frage)")[4 Port USB Hub GL850G Genesys Logic + 24V DC/DC Converter Traco Power TMA 2405S](https://old.stadtfabrikanten.org/pages/createpage.action?spaceKey=TH&title=4+Port+USB+Hub+GL850G+Genesys+Logic+%2B+24V+DC%2FDC+Converter+Traco+Power+TMA+2405S&linkCreation=true&fromPageId=62685215)
[![grafik.png](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/scaled-1680-/NfJkJYkbUDYRBNM8-grafik.png)](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/NfJkJYkbUDYRBNM8-grafik.png) 1209:8087![(Frage)](https://old.stadtfabrikanten.org/s/-6fzg5h/9012/tu5x00/_/images/icons/emoticons/help_16.svg "(Frage)")[Generic MisfitTech Nano Zero #A Axis](https://old.stadtfabrikanten.org/pages/createpage.action?spaceKey=TH&title=Smart+Stepper+rev+1%2F20%2F2019+by+MisfitTech&linkCreation=true&fromPageId=62685215)
[![grafik.png](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/scaled-1680-/NfJkJYkbUDYRBNM8-grafik.png)](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/NfJkJYkbUDYRBNM8-grafik.png) 1209:8087![(Frage)](https://old.stadtfabrikanten.org/s/-6fzg5h/9012/tu5x00/_/images/icons/emoticons/help_16.svg "(Frage)")[Generic MisfitTech Nano Zero #B Axis](https://old.stadtfabrikanten.org/pages/createpage.action?spaceKey=TH&title=Smart+Stepper+rev+1%2F20%2F2019+by+MisfitTech&linkCreation=true&fromPageId=62685215)
[![grafik.png](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/scaled-1680-/NfJkJYkbUDYRBNM8-grafik.png)](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/NfJkJYkbUDYRBNM8-grafik.png) 1209:8087![(Frage)](https://old.stadtfabrikanten.org/s/-6fzg5h/9012/tu5x00/_/images/icons/emoticons/help_16.svg "(Frage)")[Generic MisfitTech Nano Zero #C Axis](https://old.stadtfabrikanten.org/pages/createpage.action?spaceKey=TH&title=Smart+Stepper+rev+1%2F20%2F2019+by+MisfitTech&linkCreation=true&fromPageId=62685215)
[![grafik.png](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/scaled-1680-/NfJkJYkbUDYRBNM8-grafik.png)](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/NfJkJYkbUDYRBNM8-grafik.png) 1209:8087![(Frage)](https://old.stadtfabrikanten.org/s/-6fzg5h/9012/tu5x00/_/images/icons/emoticons/help_16.svg "(Frage)")[Generic MisfitTech Nano Zero #D Axis](https://old.stadtfabrikanten.org/pages/createpage.action?spaceKey=TH&title=Smart+Stepper+rev+1%2F20%2F2019+by+MisfitTech&linkCreation=true&fromPageId=62685215)
Useful tips: - [https://www.domoticz.com/wiki/PersistentUSBDevices](https://www.domoticz.com/wiki/PersistentUSBDevices) - [https://www.domoticz.com/wiki/Assign\_fixed\_device\_name\_to\_USB\_port](https://www.domoticz.com/wiki/Assign_fixed_device_name_to_USB_port) - [https://www.freva.com/2019/06/20/assign-fixed-usb-port-names-to-your-raspberry-pi/](https://www.freva.com/2019/06/20/assign-fixed-usb-port-names-to-your-raspberry-pi/) ![(Warnung)](https://old.stadtfabrikanten.org/s/-6fzg5h/9012/tu5x00/_/images/icons/emoticons/warning.svg "(Warnung)") Problem: Vendor ID and Product IDs are the same for each Smart Stepper. So they cannnot be assigned by Serial ID. The solution is to use devpath instead of Product ID and Vendor ID. The following USB port mapping was found for my Raspberr Pi 3B (browsing on the web this seems to be indivually different for each Raspberry Pi). You also can change the IDs by re-flashing the Smart Steppers. See [Smart Stepper - flashing the firmware](https://old.stadtfabrikanten.org/display/TH/Smart+Stepper+-+flashing+the+firmware) for details. [![grafik.png](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/scaled-1680-/fNrTad2194rkjg5T-grafik.png)](https://wiki.stadtfabrikanten.org/uploads/images/gallery/2026-06/fNrTad2194rkjg5T-grafik.png) ``` sudo vim /etc/udev/rules.d/99-usb-serial.rules ``` ```ini SUBSYSTEM=="tty", ATTRS{idVendor}=="1d50", ATTRS{idProduct}=="60ec", SYMLINK+="ttyUSB-DUET2ETHERNET" SUBSYSTEM=="video4linux", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="082d", ATTRS{serial}=="EF9B0F4F", SYMLINK+="ttyUSB-LOGITECH-C920" SUBSYSTEM=="tty", ATTRS{idVendor}=="05e3", ATTRS{idProduct}=="0608", SYMLINK+="ttyUSB-MINI-4PORT-HUB" #this will disappear if all Smart Steppers are disconnected because the hub itself has no tty. It gets one when at least one device is attached to the hub #ATTRS{devpath}=="3.1" -> 1 is the Port at Raspberry Pi, 1 is the Port of the connected Mini USB Hub SUBSYSTEM=="tty", ATTRS{idVendor}=="1209", ATTRS{idProduct}=="8087", ATTRS{devpath}=="1.4.1", SYMLINK+="ttyUSB-SMART-A-AXIS" SUBSYSTEM=="tty", ATTRS{idVendor}=="1209", ATTRS{idProduct}=="8087", ATTRS{devpath}=="1.4.2", SYMLINK+="ttyUSB-SMART-B-AXIS" SUBSYSTEM=="tty", ATTRS{idVendor}=="1209", ATTRS{idProduct}=="8087", ATTRS{devpath}=="1.4.3", SYMLINK+="ttyUSB-SMART-C-AXIS" SUBSYSTEM=="tty", ATTRS{idVendor}=="1209", ATTRS{idProduct}=="8087", ATTRS{devpath}=="1.4.4", SYMLINK+="ttyUSB-SMART-D-AXIS" ```

The device **ttyUSB-MINI-4PORT-HUB is not shown** by **ls /dev** if no single Smart Stepper is only!

```bash udevadm trigger #apply the rules ls /dev ``` ## Overview of busses, ports, devices USB ports are sometimes confusing. ```bash #list USB by /sys/bus/usb/drivers/usb cd /sys/bus/usb/drivers/usb ls -alF lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/ lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1.1 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.1/ lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1.2 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2/ lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1.3 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/ lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1.4 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4/ lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1.4.1 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4/1-1.4.1/ lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1.4.2 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4/1-1.4.2/ lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1.4.3 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4/1-1.4.3/ lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1.4.4 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4/1-1.4.4/ lrwxrwxrwx 1 root root 0 Apr 29 12:32 1-1.5 -> ../../../../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.5/ ``` ```bash #list USB by lsusb -t lsusb -t /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc_otg/1p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/5p, 480M |__ Port 1: Dev 3, If 0, Class=Vendor Specific Class, Driver=smsc95xx, 480M |__ Port 2: Dev 4, If 0, Class=Mass Storage, Driver=usb-storage, 480M |__ Port 3: Dev 5, If 0, Class=Communications, Driver=cdc_acm, 12M |__ Port 3: Dev 5, If 1, Class=CDC Data, Driver=cdc_acm, 12M |__ Port 4: Dev 6, If 0, Class=Hub, Driver=hub/4p, 480M |__ Port 1: Dev 8, If 0, Class=Communications, Driver=cdc_acm, 12M |__ Port 1: Dev 8, If 1, Class=CDC Data, Driver=cdc_acm, 12M |__ Port 2: Dev 9, If 1, Class=CDC Data, Driver=cdc_acm, 12M |__ Port 2: Dev 9, If 0, Class=Communications, Driver=cdc_acm, 12M |__ Port 3: Dev 10, If 0, Class=Communications, Driver=cdc_acm, 12M |__ Port 3: Dev 10, If 1, Class=CDC Data, Driver=cdc_acm, 12M |__ Port 4: Dev 11, If 0, Class=Communications, Driver=cdc_acm, 12M |__ Port 4: Dev 11, If 1, Class=CDC Data, Driver=cdc_acm, 12M |__ Port 5: Dev 7, If 0, Class=Video, Driver=uvcvideo, 480M |__ Port 5: Dev 7, If 1, Class=Video, Driver=uvcvideo, 480M |__ Port 5: Dev 7, If 2, Class=Audio, Driver=snd-usb-audio, 480M |__ Port 5: Dev 7, If 3, Class=Audio, Driver=snd-usb-audio, 480M ``` **Mapping looks like this** ``` 1-1 Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc_otg/1p, 480M 1-1 |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/5p, 480M 1-1.1 |__ Port 1: Dev 3, If 0, Class=Vendor Specific Class, Driver=smsc95xx, 480M 1-1.2 |__ Port 2: Dev 4, If 0, Class=Mass Storage, Driver=usb-storage, 480M 1-1.3 |__ Port 3: Dev 5, If 0, Class=Communications, Driver=cdc_acm, 12M 1-1.3 |__ Port 3: Dev 5, If 1, Class=CDC Data, Driver=cdc_acm, 12M 1-1.4 |__ Port 4: Dev 6, If 0, Class=Hub, Driver=hub/4p, 480M 1-1.4.1 |__ Port 1: Dev 8, If 0, Class=Communications, Driver=cdc_acm, 12M 1-1.4.1 |__ Port 1: Dev 8, If 1, Class=CDC Data, Driver=cdc_acm, 12M 1-1.4.2 |__ Port 2: Dev 9, If 0, Class=Communications, Driver=cdc_acm, 12M 1-1.4.2 |__ Port 2: Dev 9, If 1, Class=CDC Data, Driver=cdc_acm, 12M 1-1.4.3 |__ Port 3: Dev 10, If 0, Class=Communications, Driver=cdc_acm, 12M 1-1.4.3 |__ Port 3: Dev 10, If 1, Class=CDC Data, Driver=cdc_acm, 12M 1-1.4.4 |__ Port 4: Dev 11, If 0, Class=Communications, Driver=cdc_acm, 12M 1-1.4.4 |__ Port 4: Dev 11, If 1, Class=CDC Data, Driver=cdc_acm, 12M 1-1.5 |__ Port 5: Dev 7, If 0, Class=Video, Driver=uvcvideo, 480M 1-1.5 |__ Port 5: Dev 7, If 1, Class=Video, Driver=uvcvideo, 480M 1-1.5 |__ Port 5: Dev 7, If 2, Class=Audio, Driver=snd-usb-audio, 480M 1-1.5 |__ Port 5: Dev 7, If 3, Class=Audio, Driver=snd-usb-audio, 480M ``` ## Troubleshooting USB errors A lot of different USB errors can occure (like "device not accepting address"). Most times a reset of the USB hub helps. We can turn off, keep off some seconds and turn on again the hub to re-init the devices in case there are no powering issues. See [https://paulphilippov.com/articles/how-to-fix-device-not-accepting-address-error](https://paulphilippov.com/articles/how-to-fix-device-not-accepting-address-error). See [Smart Stepper - USB, Soft and hard reset](https://old.stadtfabrikanten.org/display/TH/Smart+Stepper+-+USB%2C+Soft+and+hard+reset) for some tested out handling methods (works for webcam too).