PARALLEL(HW)             XENIX System V              PARALLEL(HW)



     Name
          parallel - Parallel interface devices.

     Description
          There are several parallel devices:

          /dev/lp0  Main parallel adapter.

          /dev/lp1  Adapter on monochrome video card.

          /dev/lp2  Alternate parallel adapter (on appropriate
                    machines).

          It is not possible to have all three parallel devices on one
          system.  XT computers only allow the use of /dev/lp0. Some
          AT computers allow the use of two parallel devices,
          /dev/lp0, and either /dev/lp1, or /dev/lp2.

          If a parallel device fails to interrupt properly, the
          parallel driver enters ``poll mode.'' Once interrupts are
          received from the device, the driver returns to its original
          mode.

          The parallel driver delays a certain amount of time when a
          parallel device is closed.  The amount of delay can affect
          printer performance, but is necessary to compensate for
          different sizes of printer buffers and printer speeds.  For
          example, this command sets the delay on close to 1 second,
          specified in 10ths of a second by Ctrl-J (ASCII value 10):

               stty eol "^J" < /dev/lp0

          The default delay value is 2 seconds (^T).

     Notes
          Parallel adapters on add-on cards will function, but
          switches must be set correctly.  Some compatable computers
          have ports lp0 and lp1 reversed.

          The stty(C) command for output processing is supported on a
          parallel device.  stty options that have no effect on a
          parallel device are ignored and no error messages are
          displayed.

     Usage
          Usually invoked by through lp(C), but can be written to
          directly.

     Files
          /dev/lp0
          /dev/lp1
          /dev/lp2



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     PARALLEL(HW)             XENIX System V              PARALLEL(HW)



     See Also
          lp(C), lp(HW), lpadmin(C), lpinit(C), lpsched(C), serial(HW)





















































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