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From: gary@SPOCK.ATD.UCAR.EDU (Gary Horton)
Newsgroups: comp.laser-printers
Subject: Serial ports
Message-ID: <9009052057.AA12939@crayola.cs.UMD.EDU>
Date: 24 Aug 90 19:15:19 GMT
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Organization: National Center for Atmospheric Research, Boulder, CO
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Approved: laser-lovers@brillig.umd.edu


I'm on a Sparc 1+, running SunOS 4.1, and am attempting to
send bytes via a serial port to an HP PaintJet to 
accomplish raster graphics. I have determined that zero-filled
bytes cause confusion.  Baud and parity are fine (9600, none)
and I've used library routine ioctl() to configure the port
for 'no post-processing'.  All other values produce the
expected raster image; does anyone know what to do to 
render zeroes usefully?  Somewhere I've heard that serial
ports discard null characters unless instructed otherwise.
Oddly, with same serial port configuration, I do NOT have
this problem on an HP9876A Thermal Printer (the only diff. 
being baud here is 19200); ergo, I did not initially suspect
the port config'n.  Could it be on the printer side?

Please send replies directly to me; thanks very much for any
help!!!