User Access to Serial Port: 1) chmod 666 /dev/ttyS0 2) IMO the right way to do this is to add the user to the group which is allowed access to the device... for example: on my system, /dev/ttyS0 points to /dev/tts/0 and ls -l /dev/tts/0 gives: crw-rw---- 1 root dialout 4, 64 Dec 31 1969 /dev/tts/0 Which means that the user root has rw access and the group dialout has rw access as well. So to give a user rw access, you can simply run (as root): adduserdialout Then log out and back in and you should be all set. This is how things should work for all devices -------------------------------------------------------------------------------- Unix Terminal Utilities: cu, tip, minicom, ecu, seyon (xwindows) seyon: X Windows application. seyon -modems /dev/cuaa1 cu: connect....: cu -l /dev/cuaa1 -s 9600 disconnect.: ~. [ENTER] tip: with tip, you don't use line or speed switches as tip expects you to use an entry from the /etc/remote file (man remote): connect....: tip com2 disconnect.: ~^D To get help while the program is running, type: ~? kermit: apt-get install ckermit kermit SET LINE /dev/cuaa1 SET CARRIER-WATCH OFF connect disconnect.: hold down the Control key while pressing the \ key, then let go and press the Shift key while pressing "C". Your prompt will now look like this: C-Kermit$gt; and you can type "quit" to leave "kermit": OpenBSD: o COM1-4 will be tty00-3 on OpenBSD. For example, COM2 would be tty01 (/dev/tty01). o If you're "calling out" then you'll want to use the 'cua' devices, not the 'tty' ones. minicom is installed with permissions set at 555. To allow users to run minicom, you should put them in group dialer. If you wish to use /etc/minicom/minicom.users to restrict user behaviour to specific configurations or ports, then you must change the permissions on /usr/local/bin/minicom to be mode 4551 owned by uucp:dialer and *not* put users in group dialer. FreeBSD: COM ports are /dev/cuaa# where the # starts at 0. com1 = cuaa0.