I fiddle around with the conrad IoT Advent calendar and the provided arduino compatible. (see the website).

I downloaded the drivers for my kernel from a site that was mentioned for this in the comments, got them compiled and loaded.

But, when I attach the uc, dmesg claims to attach it to /dev/ttyUSB0, however, I only have /dev/ttyACMx devices at best. Connecting to the ttyACMx devices won't work from arduino IDE (I can select them, but no synchronisation is possible).

Output from dmesg and ls:

[ 2293.276411] usb 2-1.1: new full-speed USB device number 47 using ehci-pci
[ 2293.370530] usb 2-1.1: New USB device found, idVendor=1a86, idProduct=7523
[ 2293.370534] usb 2-1.1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[ 2293.370535] usb 2-1.1: Product: USB2.0-Serial
[ 2293.370903] ch341 2-1.1:1.0: ch341-uart converter detected
[ 2293.372877] usb 2-1.1: ch341-uart converter now attached to ttyUSB0
beowulf@:~/Downloads/CH341SER_LINUX$ ls /dev/tty
Display all 101 possibilities? (y or n)
tty        tty19      tty3       tty40      tty51      tty62      ttyS11     ttyS22     ttyS5
tty0       tty2       tty30      tty41      tty52      tty63      ttyS12     ttyS23     ttyS6
tty1       tty20      tty31      tty42      tty53      tty7       ttyS13     ttyS24     ttyS7
tty10      tty21      tty32      tty43      tty54      tty8       ttyS14     ttyS25     ttyS8
tty11      tty22      tty33      tty44      tty55      tty9       ttyS15     ttyS26     ttyS9
tty12      tty23      tty34      tty45      tty56      ttyACM0    ttyS16     ttyS27     
tty13      tty24      tty35      tty46      tty57      ttyACM1    ttyS17     ttyS28     
tty14      tty25      tty36      tty47      tty58      ttyACM2    ttyS18     ttyS29     
tty15      tty26      tty37      tty48      tty59      ttyprintk  ttyS19     ttyS3      
tty16      tty27      tty38      tty49      tty6       ttyS0      ttyS2      ttyS30     
tty17      tty28      tty39      tty5       tty60      ttyS1      ttyS20     ttyS31     
tty18      tty29      tty4       tty50      tty61      ttyS10     ttyS21     ttyS4      

Update: It seems that just seconds later the device is unmapped again although the device is still connected, at least in dmesg it is shown just some seconds later:

[34857.936151] ch341 1-1.2:1.0: ch341-uart converter detected
[34857.938144] usb 1-1.2: ch341-uart converter now attached to ttyUSB0
[34858.155575] usb 1-1.2: USB disconnect, device number 14
[34858.155799] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
[34858.155823] ch341 1-1.2:1.0: device disconnected

As requested:

beowulf:~$ lsb_release -r; uname -a
Release:    15.10
Linux powerwolf 4.2.0-19-generic #23-Ubuntu SMP Wed Nov 11 11:39:30 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Output of udevadm can be found on pastebin.

How can I get this thing working?

  • Could you update your question with out put of sudo ls -l /dev/ttyU*
    – user.dz
    Dec 2, 2015 at 22:47
  • @Sneetsher result of this is a failure since no file with /dev/ttyU* exists. I updated the dmesg output, since it seems that the driver disconnects immediatly after connecting. I guess thats a driver-problem. Dec 3, 2015 at 6:08
  • It could be, sure you have tried the change the USB port ? (1) could you edit the question and add output of lsb_release -r; uname -a so we can compare similar cases. (2) unplug the device , run udevadm monitor --env on a terminal, plug the device, ctrl+c to kill the previous command , upload output to paste.ubuntu.com . (3) If you have USB3, try disabling it.
    – user.dz
    Dec 3, 2015 at 20:41
  • @Sneetsher updated the requested information. Thank you very much for your help! Dec 4, 2015 at 6:25
  • 1
    Interesting, got a hint regarding USB-cables and tested some, with some cables it works, with other not. Dec 4, 2015 at 10:16

1 Answer 1


The workaround is to use a powered USB-Port, as well as simply another USB-Cable.

Sadly, no one seems to have a look at why with some cables the device is added and immediatly removed, while with other cables the device stays. I don't get behind this conduct.

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