LDATTACH(8)             OpenBSD System Manager's Manual            LDATTACH(8)

NAME
     ldattach - attach a line discipline to a serial line

SYNOPSIS
     ldattach [-27dehmop] [-s baudrate] [-t cond] discipline device

DESCRIPTION
     ldattach 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.

     ldattach can be run from the command line or at system startup by having
     init(8) read ttys(5) entries to attach line disciplines.

     The following options are available:

     -2      Use 2 stopbits instead of 1.

     -7      Use 7 databits instead of 8.

     -d      Do not daemonize.

     -e      Use even parity.

     -h      Turn on RTS/CTS flow control.  By default, no flow control is
             done.

     -m      Maintain modem control signals after closing the line.  Specifi-
             cally, this disables HUPCL.

     -o      Use odd parity.

     -p      Pass the data received from device to the master device of a
             pty(4) pair and vice versa.  The name of the slave device is
             written to standard output.

     -s baudrate
             Specifies the speed of the connection.  If not specified, the de-
             fault of 9600 baud is used (4800 baud for nmea(4)).

     -t cond
             nmea(4), msts(4) and endrun(4) line disciplines only.  Chooses
             the condition which will cause the current system time to be im-
             mediately copied to the terminal timestamp storage for subsequent
             use by nmea(4), msts(4) or endrun(4).  Only one can be used.

                   dcd    Copy the timestamp when DCD is asserted.
                   !dcd   Copy the timestamp when DCD is deasserted.
                   cts    Copy the timestamp when CTS is asserted.
                   !cts   Copy the timestamp when CTS is deasserted.

             If no condition is specified, the nmea(4) line discipline will
             timestamp on receiving the leading `$' character of each block of
             NMEA sentences.

     discipline
             Specifies the name of the line discipline to be attached.

                   endrun  Attach the endrun(4) line discipline.
                   msts    Attach the msts(4) line discipline.
                   nmea    Attach the nmea(4) line discipline.
                   slip    Attach the sl(4) line discipline.

     device  Specifies the name of the serial line.  device should be a string
             of the form ``cuaXX'' or ``/dev/cuaXX''.

             cua(4) devices should be used when ldattach is started from the
             command line; when started using init(8), tty(4) devices should
             be used.

     If ldattach was not started by init(8), the line discipline can be de-
     tached by killing off the ldattach process.

EXAMPLES
     To start ldattach using init(8) to attach the nmea(4) line discipline to
     /dev/tty01 at 4800 baud using a device without a carrier (DCD) line, add
     a line of the following form to /etc/ttys:

           tty01   "/sbin/ldattach nmea"   unknown on softcar

SEE ALSO
     endrun(4), msts(4), nmea(4), pty(4), sl(4), tty(4), ttys(5), init(8)

HISTORY
     The ldattach command first appeared in OpenBSD 4.3.

OpenBSD 4.7                       May 6, 2009                                2
