6.1 Serial Port Terminals
The computer considers each serial port to be a "device". It's sometimes called a terminal device since at one time terminals were the most common use for a serial port. For each such serial port there is a special file in the /dev (device) directory. /dev/tts/0 (or /dev/ttyS0) is the special file for the serial port known as COM1 in the DOS/Windows world. The device filesystem notation: tts/0 is replacing the older ttyS0 notation. But the older notation will be often used in this howto since it is still widely used and often still works (using symbolic links) on the newer device filesystems.
To send text to a terminal you may redirect standard output of some command-line command to the appropriate special file. For example typing "echo test > /dev/ttyS1" at the command prompt should send the word "test" to the terminal on ttyS1 (COM2) provided you have write permission on /dev/ttyS1. Similarly, typing "cat my_file > /dev/ttyS0" will send the contents of the file my_file to COM1 (ttyS0).
* License
