Permissions for accessing Serial ports

English Hardware
#1

I am unable to access a serial port as normal user in OS 11.2.

The ownership for the port,/dev/ttyS0 belongs to root:dialout. Group dialout has RW permissions.So,I guess the user has to belong to ‘dialout’ group.Even after a user is included in dialout port,still the user is unable to access,“Permission is Denied”.

Before OS 11.2,I used to make the users members of group “uucp” to get serial port access.I tried that also in OS 11.2,without luck.So,I have to be root to access it.

This requirement itself seems to be one of the fossils of old time Linux where for normal usage of PC resources,one needed elevated privileges.I guess the trend now is to let the user do all PC work,but in a safe way.

#2

After you added the user, did you logout and login again? Group membership is only evaluated once, as the beginning of a login session. I certainly can access /dev/ttyS0 after adding myself to dialout, then logging out and in again.