Re: [PARPORT] bidirectional parallel port

Tim Waugh (
Sun, 27 Jun 1999 17:07:43 +0100 (GMT)

On Sun, 27 Jun 1999, Christian Bucher wrote:

> - does someone know what the difference between this bidirectional and
> other parallel ports are?

If it's a bidirectional port, that just means that the data lines can be
driven by the peripheral as well as the host (although obviously not at
the same time).

> - do you think it's possible to read from the scanner with other
> parallel ports?

I don't know.

> - do you think it's possible to read from the scanner using the
> lp, parport driver etc. ?

Not easily as they are at the moment. I have a patch for 2.3 which adds
IEEE 1284 support (various transfer protocols over the parallel port),
and I've got a design for a device driver for /dev/parport, so that
user-space programs can use it.

> - do the parport driver supports bidirectional ports too?

Yes. Parport_pc can detect whether or not a given port is bidirectional.
The IEEE 1284 code I have knows how to use the bidirectional capability


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This archive was generated by hypermail 2.0b3 on Sun 27 Jun 1999 - 12:31:00 EDT