I'm not sure if I have a problem or not, but would be grateful for some guidance.

I have three distinct types of serial port on my slackware 10.2 machine:

standard ttyS0 - ttyS1
multi-port serial card ttyD000 - ttyD007
remote terminal server ports ttyCC00 - ttyCC07

If I do ls -al /dev/ttyS0 as root, I get the following response from:

crw-rw---- 1 root uucp 4, 64 2006-3-20 22:18 /dev/ttyS0

I thought it should be owned by root and tty.

Similarly, if I do the same for /dev/ttyD000 or /dev/CC00 I get:

crw--w--w-- 1 root root ..... etc

which I understand to mean that it is owned by root and root.

If these are wrong, how can I change them to be owned by the proper groups?

Thanks
Roger

If your system uses udev you will need to modify the rules which are used to create these files in /dev - better yet - put the adapted rules in a file which gets parsed before the standard file.
This way your changes will still be there after the file got updated someday - and thus overwritten.

The filename and location should be:
/etc/udev/rules.d/50-udev.rules - at least that is how it is here on my system.

The files in this directory are parsed in lexical order and rules are applied only once for a given device - so your rules need to come before the default.
Calling the file 10-my.rules will do that (10 takes care of it being the first file parsed - the ending .rules is mandatory - else it will be ignored).

If your system does not use udev, you can simply change the owner of the device file:
chown root:tty /dev/ttyS0

Thanks very much for your help

I have /etc/udev/rules.d/udev.rules and had a look at that. Slightly odd because all the tty devices were already shown as belonging to group tty. Anyway, I have followed your second advice and changed the ownerships of all the devices, and everything seems well. (so far.....!)