# USB serial converter CP2102 /dev/ttyU0 permissions



## holala (Aug 13, 2020)

Hello,

I'm struggling to find what group should I add my user in order to access /dev/ttyU0.
With the root user it works. My user is added to the wheel and dialer groups (on Linux it is the dialout group). May you suggest how to fix this permission problem?

Thanks!


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## tingo (Aug 13, 2020)

the groups dialer or cups are common, but you also need to check what owner, group and permission /dev/ttyU0 has. Simply `ls -l /dev/ttyU0` and you will find out.


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## holala (Mar 13, 2021)

Sure, it is permission related issue. My /dev/ttyU0 was readable only by the owner, crw-------.
In /usr/local/etc/devd/ I created a file usbserial.conf with the following content:

```
notify 100 {
    match "system"        "DEVFS";
    match "subsystem"    "CDEV";
    match "type"        "CREATE";
    match "cdev"        "ttyU[0-9]+";
    action "chmod g+rw /dev/$cdev";
};
```

Then `service devd restart` and now I have non-root access to the usb serial.


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