How to check and use serial ports under Linux

How to check and use serial ports under Linux

How do I check and configure serial ports under Linux for various purposes such as modem, null ing null
Modems or connect a dumb terminal?


Linux offers various tools. Linux uses ttysx for a serial port device name. For example, COM1 (DOS/Windows Name) is ttys0, com2 is ttys1 and so on.

Task: Display detected system's serial support

Simple run dmesg command
$
dmesg | grep tty

Output:

[   37.531286] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A[   37.531841] 00:0b: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A[   37.532138] 0000:04:00.3: ttyS1 at I/O 0x1020 (irq = 18) is a 16550A

Setserial command

Setserial is a program designed to set and/or report the configuration information associated with a serial port. this information provided des what I/O port and IRQ a particle serial port is using, and whether or not the Break Key shocould be interpreted as
Secure attention key, and so on. Just type the following command:
$
setserial -g /dev/ttyS[0123]

Output:

/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4/dev/ttyS1, UART: 16550A, Port: 0x1020, IRQ: 18/dev/ttyS2, UART: unknown, Port: 0x03e8, IRQ: 4/dev/ttyS3, UART: unknown, Port: 0x02e8, IRQ: 3

Setserial with-G option help to find out what physical serial ports your Linux box has.

LINUX serial console programs

Once serial ports identified you can configure Linux box using various utilities:

1. Minicom-
   The best friendly serial communication program for controlling modems and connecting to dump Devices
2. Wvidial
   Or other GUI Dial Up Networking Program-a PPP dialer with built-in intelligence.
3. Getty/agetty-agetty opens a tty port, prompts for a login name and invokes the/bin/LOGIN command.
4. Grub/lilo configuration-to configure serial port as the system console