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

NAME
     nmdm -- nullmodem terminal	driver

SYNOPSIS
     To	compile	this driver into the kernel, place the following line in your
     kernel configuration file:

	   device nmdm

     Alternatively, to load the	driver as a module at boot time, place the
     following line in loader.conf(5):

	   nmdm_load="YES"

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 con-
     figured in	the termios(4) settings.  The speed emulation works indepen-
     dently in the two directions, controlled by the slower end's termios set-
     tings (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 access-
     ing 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 23, 2018				   BSD

NAME | SYNOPSIS | DESCRIPTION | FILES | DIAGNOSTICS | SEE ALSO | HISTORY

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