neff@hpvcfs1.HP.COM (Dave Neff) (07/27/89)
I have been conspicuously silent with respect to the Atari ST parallel port current sink limit and DeskJet/DeskJet+ pullup resistors. You see, here's my dilema: The Atari ST is not officially supported for use with the DeskJet printers. This means we have not tested the printer and our support people will be next to useless in resolving problems. They won't tell you to "take a hike, its not supported", rather our support people simply lack Atari expertise to help with any significant technical problems. Furthermore, I am unable to test and verify any of the proposed solutions to the current limit problem. Using the 7407 buffer on the data and strobe lines should work fine, but as an HP representative I cannot say this is the "HP recommended" solution. You also could use the serial port at 19.2 K baud (in most cases this will not hurt performance) but I have been told by Atari users there are various gotchas when trying to print out the serial port. I still fail to understand how the DeskJet+ could damage an Atari, even though there is one case of anecdotal evidence to the contrary. The current limit could result in marginal logic levels on data and especially strobe, but if the Atari can only sink 1.6ma thats fine, and if the printer tries to draw more the Atari simply cannot supply it -- how can this damage the Atari? If I had an Atari I would definately buffer the parallel port with the 7407 for logic level reliability if nothing else. If you have sent me mail about this problem and I haven't answered I'm sorry and I hope this posting explains the situation somewhat. I hope this posting is at least slightly better than nothing. I have encouraged our support people to make a specific statement on Atari support especially relating to the current limit on the parallel port but so far they have not come up with an official position. Dave Neff neff@hpvcfs1.HP.COM
avogel@ms.uky.edu (Andrew Lee Vogel) (07/27/89)
I have built a cable with the 7407s and use the Tools TeX driver
with no problems, no problems about turning on the computer and
printer in various orders either.
I do have one question, some hp laserjet drivers work and some don't.
My observation: Is it the case that the drivers that work have the
computer do "everything" while those that don't
want to download fonts to the printer? When attempting
to print TeX with a driver that doesn't work the
built in printer fonts are used
and so a mess is created.
neff@hpvcfs1.HP.COM (Dave Neff) (08/01/89)
> I do have one question, some hp laserjet drivers work and some don't. > My observation: Is it the case that the drivers that work have the > computer do "everything" while those that don't > want to download fonts to the printer? When attempting > to print TeX with a driver that doesn't work the > built in printer fonts are used > and so a mess is created. Basically correct. The DeskJet+ is LaserJet compatable when printing graphics with no random cursor moves (i.e. top to bottom of the page) and when printing fixed pitch fonts. The DeskJet+ is not LaserJet compatable for proportional spaced fonts, random cursor moves, and font downloads. Try to get a DeskJet driver to insure proper behavior and best performance. TeX generally uses allot of downloads. The DeskJet+ does not use LaserJet soft font formats because: 1) DeskJet fonts are really 600 DPI horizontally (with consecutive dot restrictions) which does make a difference in print quality. LaserJet fonts are 300 DPI. 2) DeskJet fonts use data compression to fit more fonts in less RAM. LaserJet fonts do not. 3) To use fewer total font characters, the DeskJet will build compounded chars out of basic components. The LaserJet does not use compound components. This allows the LaserJet to easily download selective characters but the DeskJet must download an entire character set mainly due to this problem. I hear versions of TeX are coming out that do everything in graphics and make no use of downloads. I am not a TeX user so don't have any pointers to sources handy. Dave Neff neff@hpvcfs1