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
Check Out this Related Man Page
PTY(4) BSD Kernel Interfaces Manual PTY(4)NAME
pty -- BSD-style compatibility pseudo-terminal driver
SYNOPSIS
device pty
DESCRIPTION
The pty driver provides support for the traditional BSD naming scheme that was used for accessing pseudo-terminals. When the device
/dev/ptyXX is being opened, a new terminal shall be created with the pts(4) driver. A device node for this terminal shall be created, which
has the name /dev/ttyXX.
New code should not try to allocate pseudo-terminals using this interface. It is only provided for compatibility with older C libraries that
tried to open such devices when posix_openpt(2) was being called.
FILES
The BSD-style compatibility pseudo-terminal driver uses the following device names:
/dev/pty[l-sL-S][0-9a-v] Pseudo-terminal master devices.
/dev/tty[l-sL-S][0-9a-v] Pseudo-terminal slave devices.
DIAGNOSTICS
None.
SEE ALSO posix_openpt(2), pts(4), tty(4)HISTORY
A pseudo-terminal driver appeared in 4.2BSD.
BUGS
Unlike previous implementations, the master slave device nodes are destroyed when the PTY becomes unused. A call to stat(2) on a nonexistent
master device will already cause a new master device node to be created. The master device can only be destroyed by opening and closing it.
The pty driver cannot be unloaded, because it cannot determine if it is being used.
BSD August 20, 2008 BSD
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