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.