Re: [PARPORT] Re: carefully does it

Tim Waugh (
Mon, 3 May 1999 11:00:54 +0100 (GMT)

On Mon, 3 May 1999, Andrea Arcangeli wrote:

> > root@laser:/home/andrea# tunelp /dev/lp0 -s
> /dev/lp0 status is 119, busy, out of paper, on-line, error
> ^^^^^^^^^^^^ ^^^^^
> Fine. It seems your patch would work fine here too, and it seems the right
> thing to do (I don't have any spec though).

Annex C (informative) of IEEE 1284 gives a little more information than I
first realised. C.3 claims to lay out the "core specifications for the
classic Centronics Standard Parallel Interface", taken from Centronics
Engineering Standard Number 9, Revision B, dated April 9, 1980.

It says that Busy is active "when the printer cannot receive data" and
also "when the paper-empty and/or fault status line is true or an input
prime is present". Also, a "paper-empty condition also causes the fault
and busy lines to be active", and "the nonselect condition (de-select)
causes the busy and fault lines to be active".

However, pointing at standards is near useless for this particular
interface, because there are many variations in common use. But it seems
we are faced with a choice between losing data when out of paper, or not
being able to print at all, _if_ this issue is causing the problems.


-- To unsubscribe, send mail to: --
-- with the single word "unsubscribe" in the body of the message. --

This archive was generated by hypermail 2.0b3 on Mon 03 May 1999 - 06:27:15 EDT