Copyright (c) 2007, 2008 Marc Balmer <mbalmer@openbsd.org>
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.Dd $Mdocdate: October 1 2014 $ .Dt LDATTACH 8 .Os .Sh NAME .Nm ldattach .Nd attach a line discipline to a serial line .Sh SYNOPSIS .Nm ldattach .Op Fl 27dehmop .Op Fl s Ar baudrate .Op Fl t Ar cond .Ar discipline .Ar device .Sh DESCRIPTION .Nm is used to attach a line discipline to a serial line to allow for in-kernel processing of the received and/or sent data. Depending on the line discipline being attached, one or more options may be applied.
p .Nm can be run from the command line or at system startup by having .Xr init 8 read .Xr ttys 5 entries to attach line disciplines.
p The following options are available: l -tag -width Ds t Fl 2 Use 2 stopbits instead of 1. t Fl 7 Use 7 databits instead of 8. t Fl d Do not daemonize. t Fl e Use even parity. t Fl h Turn on RTS/CTS flow control. By default, no flow control is done. t Fl m Maintain modem control signals after closing the line. Specifically, this disables HUPCL. t Fl o Use odd parity. t Fl p Pass the data received from .Ar device to the master device of a .Xr pty 4 pair and vice versa. The name of the slave device is written to standard output. t Fl s Ar baudrate Specifies the speed of the connection. If not specified, the default of 9600 baud is used (4800 baud for .Xr nmea 4 ) . t Fl t Ar cond .Xr nmea 4 , .Xr msts 4 and .Xr endrun 4 line disciplines only. Chooses the condition which will cause the current system time to be immediately copied to the terminal timestamp storage for subsequent use by .Xr nmea 4 , .Xr msts 4 or .Xr endrun 4 . Only one can be used.
p l -tag -width DCDXX -offset indent -compact t dcd Copy the timestamp when DCD is asserted. t !dcd Copy the timestamp when DCD is deasserted. t cts Copy the timestamp when CTS is asserted. t !cts Copy the timestamp when CTS is deasserted. .El
p If no condition is specified, the .Xr nmea 4 line discipline will timestamp on receiving the leading .Sq $ character of each block of NMEA sentences. t Ar discipline Specifies the name of the line discipline to be attached.
p l -tag -width nmeaXX -offset indent -compact t endrun Attach the .Xr endrun 4 line discipline. t msts Attach the .Xr msts 4 line discipline. t nmea Attach the .Xr nmea 4 line discipline. .El t Ar device Specifies the name of the serial line. .Ar device should be a string of the form .Dq cuaXX or .Dq /dev/cuaXX .
p .Xr cua 4 devices should be used when .Nm is started from the command line; when started using .Xr init 8 , .Xr tty 4 devices should be used. .El
p If .Nm was not started by .Xr init 8 , the line discipline can be detached by killing off the .Nm process. .Sh EXAMPLES To start .Nm using .Xr init 8 to attach the .Xr nmea 4 line discipline to
a /dev/tty01 at 4800 baud using a device without a carrier (DCD) line, add a line of the following form to
a /etc/ttys : d -literal -offset indent tty01 "/sbin/ldattach nmea" unknown on softcar .Ed .Sh SEE ALSO .Xr endrun 4 , .Xr msts 4 , .Xr nmea 4 , .Xr pty 4 , .Xr tty 4 , .Xr ttys 5 , .Xr init 8 .Sh HISTORY The .Nm command first appeared in .Ox 4.3 .