duart(7)                       DG/UX R4.11MU05                      duart(7)


NAME
       duart - Dual Universal Asynchronous Receiver/Transmitter

SYNOPSIS
       duart([controller-num[,port]])

DESCRIPTION
       The duart device driver accesses a Dual Universal Asynchronous
       Receiver/Transmitter serial line device.  Each duart device supports
       up to two asynchronous serial ports.  To configure a duart
       controller, you must add a device name entry of the form described
       above to the DG/UX system configuration file.  The parameters in a
       device name have the following meanings:

       ·   The controller-num parameter is a hexadecimal number in the range
           0 through 9 which distinguishes the various instances of the
           controller that are available.  The default value for controller-
           num is 0.  All DG/UX systems have either one or two duart devices
           integrated onto the system board or the primary I/O Controller
           (IOC) board.  On systems that can support multiple IOCs, two more
           integrated duart devices will be present on each additional IOC.
           The devices on the first IOC are named duart(0) and duart(1); the
           devices on the second IOC are named duart(2) and duart(3); and so
           on.

       ·   The port parameter is a hexadecimal number which identifies a
           particular asynchronous serial port on the duart device.  The
           first physical port on the device use port number 0 and the
           second uses port number 1.  The default value for port is 0.

       These ports present the standard terminal interface described in
       termio(7), except for the following unsupported features:

       ·   The PAREXT parity setting

       ·   The B50, B200, B34800 and EXTB baud rates

       ·   The stty options for hardware flow control via carrier detect
           (cdxon) and isochronous hardware flow control (isxoff)

       ·    The CDXON or ISXOFF flags of the x_hflag field of the termiox
           structure

FILES
       When a duart controller is configured, it creates a character-special
       device node for each available serial port, using the pathname:

           /dev/async/line/duart(controller-num,port)


       Note that every possible port on the device may not be available.  On
       some machines, the duart(1) device has only one port physically
       present on the back of the system cabinet.  A graphics workstation
       will reserve one of the ports for use as the /dev/mouse mouse device,
       while a non-graphics systems will reserve a different port for use as
       the /dev/syscon system console device.  See your hardware
       documentation for details.

       The chk.devlink command is responsible for creating and maintaining
       an additional link to each port device node, with a pathname of the
       form /dev/tty[0-9]*.  See the chk.devlink(1M) and devlinktab(4M) man
       pages for details.

EXAMPLES
       The following entries in a DG/UX configuration file configure the
       first two standard DUART devices (and thus, all available ports on
       each device):

            duart(0)
            duart(1)


SEE ALSO
       mouse(7), termio(7), termiox(7), chk.devlink(1M), devlinktab(4M).






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