NMDM(4)

NAME
nmdm - nullmodem terminal driver

SYNOPSIS
device nmdm

DESCRIPTION
The nmdm driver provides support for a device-pair termed a null modem pair. A null modem pair is a pair of character devices. Each device provides to a process an interface identical to that described in tty(4). However, whereas most other devices which provide the interface described in tty(4) have a hardware device of some sort behind them, the nmdm device has, instead, another process manipulating it through the other half of the pair. That is, anything written on the first device is given to the second device as input and anything written on the second device is presented as input on the first device.

FILES
/dev/nmdmN[AB]
    nullmodem device nodes. Where the A node has a matching B node.

DIAGNOSTICS
None.

SEE ALSO
tty(4)

HISTORY
The nmdm driver first appeared in FreeBSD 4.4.