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XTEND(8)                FreeBSD System Manager's Manual               XTEND(8)

     xtend - X-10 daemon


     Xtend interfaces between user-level programs and the TW523 X-10
     controller.  It logs all packets received from the TW523, attempts to
     track the status of all X-10 devices, and accepts socket connections from
     user-level client programs that need to manipulate X-10 devices.

     When xtend is started, it forks, releases the controlling terminal, then
     opens its log file, where it subsequently records all X-10 activity and
     diagnostic messages.  It then begins processing packets received from the
     TW523 and accepting connections one at a time from clients wishing to
     issue X-10 commands.  Xtend is started from /etc/rc.i386 startup script
     if enabled in /etc/rc.conf script.

     Sending xtend a SIGHUP causes it to close and reopen its log file.  This
     is useful in shell scripts that rotate the log files to keep them from
     growing indefinitely.  If xtend receives a SIGTERM, it shuts down
     gracefully and exits.  A SIGPIPE causes xtend to abort the current client

     Xtend communicates with client processes by a simple protocol in which a
     one-line command is sent by the client, and is acknowledged by a one-line
     response from the daemon.

     Xtend understands four types of commands:

     status H U   where H is a single letter house code, and U is a numeric
                  unit code, causes xtend to respond with one line of status
                  information about the specified device.

     send H U N   where H is a single-letter house code, U is either a numeric
                  unit code or a function code (see source file
                  xtend/packet.c) for a list, and N is a number indicating the
                  number of times (usually 2) the packet is to be transmitted
                  without gaps, causes xtend to perform the specified X-10
                  transmission.  If the transmission was apparently
                  successful, a single-line response containing OK is issued,
                  otherwise a single-line response containing ERROR is

     dump         causes xtend to dump the current status of all devices to an
                  ASCII file in the spool directory.  The response OK is
                  issued, regardless of whether the status dump was

     monitor H U  causes xtend to add the current client socket connection to
                  a list of clients that are to be notified about activity
                  concerning the specified X-10 device.  The single-line
                  acknowledgement OK is returned if the maximum (currently 5)
                  number of such clients was not exceeded, otherwise ERROR is
                  returned.  Xtend then returns to its normal mode of
                  accepting connections from clients.  However, each
                  subsequent change in the status of the specified device will
                  cause xtend to write one line of status information for the
                  device (in the same format as produced by the status
                  command) to the saved socket.  This feature is useful for
                  writing programs that need to monitor the activity of
                  devices, like motion detectors, that can perform X-10


     xten(1), tw(4)

     /dev/tw0                    the TW523 special file
     /var/run/tw523              socket for client connections
     /var/run/          pid file
     /var/spool/xten/Log         log file
     /var/spool/xten/Status      device status file (binary)
     /var/spool/xten/status.out  ASCII dump of device status

     There is currently no timeout on client socket connections, so a hung
     client program can prevent other clients from accessing the daemon.

     Xtend does the best it can at trying to track device status, but there is
     usually no way it can tell when a device has been operated manually.
     This is due to the fact that most X-10 devices are not able to respond to
     queries about their status.

     Eugene W. Stark <>

FreeBSD 11.0-PRERELEASE        October 30, 1993        FreeBSD 11.0-PRERELEASE


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