No Permission to /dev/ttyUSB on Debian

2
votes

I am using Debian 8.0 and have a USB->Serial Port Adapter

Bus 001 Device 004: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port

It is listed in /dev/ as ttyUSB0, but i can't use ist. I am in the group 'dialout', too.

crw-rw---- 1 root dialout 188, 0 Jan  4 10:38 /dev/ttyUSB0

If i try to use it by

/dev/ttyUSB0

the output is (no permission):

-bash: /dev/ttyUSB0: Keine Berechtigung

I tried reboots and so an, but it won't work. Is there anyone with an idea for this problem?

1
serial-portraspberry-piusbdebian
What does the groups command give you as result? – flo
pi adm dialout cdrom sudo audio video plugdev games users input netdev gpio i2c spi – Listener

1 Answers

2
votes

The message /dev/ttyUSB0: Keine Berechtigung (permission denied) is telling you, that your group lacks the x permission. Nevertheless, it is kind of missleading, as you cannot use it that way, even it you had the permission.

/dev/ttyUSB0 is like a file. You can write to it (eg echo "hello USB" > /dev/ttyUSB0) and you can read from it (eg cat /dev/ttyUSB0).

If you want to use the port that way, you may need to use stty to set the the port's parameter (like the speed).

Another, simpler way, is to install and use a terminal programm like minicom.