serial(7)                                               serial(7)



NAME
     serial - provides the on-board serial ports

DESCRIPTION
     /dev/tty0 is the serial port connected to the DIN  connector
     on  the rear of the chassis with the modem icon above it; it
     is  linked  to  (is  the  same  as)  the  name   /dev/modem.
     /dev/tty1  is the serial port connected to the DIN connector
     on the rear of the chassis with the printer icon  above  it;
     it is linked to (is the same as) the name /dev/printer.

     These ports  support  all  the  standard  A/UX  ioctls  from
     termio(7).    They   also  support  the  following  hardware
     specific extensions.  The modes set by these ioctls (or  the
     corresponding  stty(1)  options)  persist  after a device is
     closed  and  reopened.   The  mnemonic  definitions  are  in
     /usr/include/sys/ioctl.h.

     UIOCNOMODEM
          No modem control, the input line HSKi is ignored.   The
          output  line  HSKo  is  asserted  whenever  the line is
          opened.  The following stty(1) command can be  used  to
          put  a  port  (/dev/tty0  in  this example) into such a
          mode:

             stty -modem < /dev/tty0

     UIOCMODEM
          Modem  control,  the  output  line  HSKo  is   asserted
          whenever  a process is attempting to open the device or
          while the device is open, as an  output  this  performs
          the  RS232  function Data Terminal Ready (DTR).  When a
          port is closed this line is negated (if the HUPCL  flag
          from  termio(7) is set) which causes a modem to hang up
          a call.  Upon opening, if HSKi is not asserted, then an
          open  will  not  complete  (a process will be suspended
          until the open does complete)  until  it  is  asserted.
          Processes that use the O_NDELAY (see open(2)) flag when
          opening such a port  are  not  suspended,  but  instead
          complete their opening immediately.  If HSKi is negated
          while a  port  is  open,  the  signal  SIGHUP  will  be
          generated   to   processes   with  the  port  as  their
          controlling terminal (usually resulting in the death of
          the  processes and the subsequent closing of the port).
          In this mode, the HSKi input  functions  as  the  RS232
          function  Data  Carrier  Detect  (DCD).   The following
          stty(1) command can be used to put a port into  such  a
          mode:

             stty modem < /dev/tty0





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serial(7)                                               serial(7)



          To turn this option off, stty(1) needs  to  first  open
          the  port; and because it can't open the port until the
          HSKi (DCD) line is asserted, the following form of  the
          stty(1) should be used to turn off this option:

             stty -n /dev/tty0 -modem


     UIOCDTRFLOW
          DTR flow control.  This mode  is  used  to  communicate
          with  printers  such  as the Apple ImageWriter II.  The
          HSKo output performs in the same manner as above.   The
          HSKi  input  is used to enable or disable output by a a
          device (such as a printer) that wishes to flow  control
          it.   When  HSKi  is asserted characters may be output,
          when it is negated output will stop.  Note that when an
          A/UX  device  is closed, the process that is closing it
          will be suspended until  all  waiting  characters  have
          been  transmitted;  such a process will wait until flow
          control is asserted.  Either of the  following  stty(1)
          commands can be used to turn on DTR flow control:

             stty dtrflow < /dev/tty0
             stty hxctl < /dev/tty0


     UIOCTTSTAT
          This call returns the current state of the three  above
          options; refer to termio(7) for more documentation.

             Note:  Since this interface does not support  the
             RS232  ``Clear  To Send'' and ``Request To Send''
             (CTS/RTS), the ioctls UIOCFLOW and UIOCNOFLOW are
             not  supported.   In  UIOCDTRFLOW  mode, the HSKi
             input acts very similarly to  CTS  and  could  be
             used with some devices that require this signal.

          The port pins have the following functions, shown  with
          the connections required to use them for RS232:

                    Mini-DIN
                     Pin #     Function   RS232   Pin #
                    ___________________________________

                    1          HSKo       DTR      20

                    2          HSKi       DCD       8

                    3          TXD-       TXD       3

                    4          GND        GND       7

                    5          RXD-       RXD       2

                    6          TXD+       GND       7

                    7          GPi        NC

                    8          RXD+       GND       7





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serial(7)                                               serial(7)



FILES
     /dev/tty0
          Device file
     /dev/tty1
          Device file
     /dev/modem
          Device file
     /dev/printer
          Device file
     /usr/include/sys/ioctl.h
          Header file

SEE ALSO
     termio(7)

     stty(1) in A/UX Command Reference ioctl(2), open(2) in A/UX
     Programmer's Reference






































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