TTYS(4)

NAME
       ttys - serial terminal lines

DESCRIPTION
       ttyS[0-3]  are  character  devices for the serial terminal
       lines.

       They are typically created by:
              mknod -m 660 /dev/ttyS0  c  4  64  #  base  address
              0x03f8
              mknod  -m  660  /dev/ttyS1  c  4  65 # base address
              0x02f8
              mknod -m 660 /dev/ttyS2  c  4  66  #  base  address
              0x03e8
              mknod  -m  660  /dev/ttyS3  c  4  67 # base address
              0x02e8
              chown root.tty /dev/ttyS[0-3]

FILES
       /dev/ttyS[0-3]

SEE ALSO
       mknod(1) chown(1) getty(1) tty(4)