From: davea@col.hp.com (David E Allen)
Date: Mon, 1 Apr 1991 19:46:18 GMT
Subject: Re: Problem using HP II P  laserprinter  with 1040 ST
Message-ID: <16830011@col.hp.com>
Organization: HP Colorado Springs Division
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!hp-col!col!davea
Newsgroups: comp.sys.atari.st
References: <1991Mar27.150249@kboeng.enet.dec.com>

logajan@ns.network.com (John Logajan) /  9:02 pm  Mar 27, 1991 /
> I have discovered that if the Atari ST parallel (printer) port 
> STROBE line (normally high) is pulled toward ground (low) by a 
> heavy load (such as a powered-off HP DeskJet Plus), the ST STROBE 
> line will thereafter stay low until the load is removed (by 
> powering up the DJ+)
> 6.) Install a PNP transistor in the STROBE line.
>                           -----> Ground
>                           !
>                          / C
>                      B !/
> from Atari STROBE >----!
>                        !\
>                          \ E
>                          !
>                          ----------> to Printer STROBE

Would just a diode work - connected in the STROBE line with cathode towards
the Atari? It would be simpler to wire in. It would prevent the printer
from pulling the atari low on this line. It would require the Atari to
sink more current in the low state (than the transistor), but not any more
than with the direct connection.

dave allen