В файле Linux devices.txt в документации ядра написано:
3 char Pseudo-TTY slaves
0 = /dev/ttyp0 First PTY slave
1 = /dev/ttyp1 Second PTY slave
...
255 = /dev/ttyef 256th PTY slave
These are the old-style (BSD) PTY devices; Unix98
devices are on major 136 and above.
и продолжает говорить
4 char TTY devices
0 = /dev/tty0 Current virtual console
1 = /dev/tty1 First virtual console
...
63 = /dev/tty63 63rd virtual console
64 = /dev/ttyS0 First UART serial port
...
255 = /dev/ttyS191 192nd UART serial port
UART serial ports refer to 8250/16450/16550 series devices.
Older versions of the Linux kernel used this major
number for BSD PTY devices. As of Linux 2.1.115, this
is no longer supported. Use major numbers 2 and 3.
Я не знаю, насколько это вам поможет, но вы должны начать в правильном направлении.