freebsd man page for nmdm

NMDM(4) 						   BSD Kernel Interfaces Manual 						   NMDM(4)

NAME
     nmdm -- nullmodem terminal driver

SYNOPSIS
     device nmdm

DESCRIPTION
     The nmdm driver provides two tty(4) devices connected by a virtual ``null modem'' cable.

     If either of the two tty devices have the CDSR_OFLOW bit (``stty dsrflow'') set in their line discipline, the nmdm device will emulate the
     speed configured in the termios(4) settings.  The speed emulation works independently in the two directions, controlled by the slower end's
     termios settings (c_ispeed, c_ospeed, CS5 ... CS8, CSTOPB and PARENB).

FILES
     /dev/nmdmN[AB]  nullmodem device nodes.  Where the A node has a matching B node.

     The nmdm driver implements ``on-demand device creation'' so simply accessing a given instance in /dev will create it.

DIAGNOSTICS
     None.

SEE ALSO
     stty(1), termios(4), tty(4)

HISTORY
     The nmdm driver first appeared in FreeBSD 4.4.

BSD
								 January 27, 2005							       BSD