NMDM(4) Kernel Interfaces Manual NMDM(4) NAME nmdm -- nullmodem terminal driver 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 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 con- figured in the termios(4) settings. The speed emulation works indepen- dently in the two directions, controlled by the slower end's termios set- tings (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), ttys(5) HISTORY The nmdm driver first appeared in FreeBSD 4.4. FreeBSD 15.1 July 11, 2020 NMDM(4)
NAME | SYNOPSIS | DESCRIPTION | FILES | DIAGNOSTICS | SEE ALSO | HISTORY
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