Most embedded Linux/BSD Systems such as router, switch, servers, and NAS device comes with console port interface (RS-232). RS-232 is used for communicating to headless server, where no monitor or keyboard installed during boot when operating system is not running yet and therefore no network connection is possible. You need to use serial cable between your computer and embedded system server or router. On this post, i will share to you how to make it connect with terminal linux command. There are many commands that can use it.
If you want to connect your computer with serial port devices, first you must find out information about your serial port.
Type the following dmesg command :
$ dmesg | egrep --color 'serial|ttyS'
[ 1.245258] serial8450: tty0 at I/O 0x3f8 (irq = 4) is a 16550A
[ 1.265727] serial8450: tty1 at I/O 0x2f8 (irq = 3) is a 16550A
[ 1.286713] 00:07: tty0 at I/O 0x3f8 (irq = 4) is a 16550A
[ 1.307321] 00:08: tty1 at I/O 0x2f8 (irq = 3) is a 16550A