table of contents
NMDM(4) | Device Drivers Manual | NMDM(4) |
NAME¶
nmdm
—
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¶
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¶
stty(1), termios(4), tty(4)HISTORY¶
Thenmdm
driver first appeared in
FreeBSD 4.4.
January 23, 2018 | Linux 4.19.0-10-amd64 |