NAME
nmdm —
nullmodem terminal driver
SYNOPSIS
device nmdm
DESCRIPTION
Thenmdm 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
HISTORY
The nmdm driver first appeared in
FreeBSD 4.4.