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From: laser-lovers@ucbvax.UUCP
Newsgroups: mod.computers.laser-printers
Subject: Re: Hooking up an HP Laser Printerto an Altos 86
Message-ID: <8601190814.AA09057@uw-beaver.arpa>
Date: Sun, 19-Jan-86 03:14:08 EST
Article-I.D.: uw-beave.8601190814.AA09057
Posted: Sun Jan 19 03:14:08 1986
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(I would have preferred to answer this by private mail, but the Berkeley
laser-lovers gateway skillfully deleted the original sender's address...
Until something is done about this, signing submissions might be a good
idea if you want private replies.)

[[Editor's note:  This has been reported to Berkeley already once or
twice.  I'll mention it to them again.		--Rick ]]

If the HP printer cost $2-3k, it probably is a LaserJet, perhaps by another
name.  The only pre-LaserJet HP laser printers were big expensive ones.

The major problem likely to arise in getting a LaserJet onto an Altos (or
most any Unix system) is getting an 8-bit output path that respects XON/XOFF
flow control.  On SysV it can be done straightforwardly, barring problems
with stupid "smart" hardware.  On x.yBSD there is a bit that claims to do
the right thing, but there is some problem about getting it set properly
(need to ioctl twice?  I forget...).  On V7-derived systems, you're in
trouble unless you have sources and can tinker with the terminal driver.

The LaserJet will also do hardware handshaking, although this was not
documented in early manuals.  (It is documented in newer ones -- the
LaserJet manual has been through *at least* two substantial revisions.
The most modern edition of the manual is two parts, the Operator's
Reference Manual, 02686-90914, and the Technical Reference Manual,
02686-90915; you might want to order these from HP.  You need both.)
The printer will drop DTR to say "stop"; you will need a cable that runs
this line to the right pin on your computer, perhaps CTS or DSR.  And you'll
need a system that pays attention to such flow control, which some don't.
Note that running *both* hardware and XON/XOFF handshaking probably is
not going to work!

The early LaserJet manuals also did not document how to change the baud
rate.  Again, getting new manuals is the simplest answer to this.  (If
desperate, send me mail.)  You're likely to find it set for 9600 baud if
the manual is old enough not to describe how to change it, since that's
the factory default.  One stop bit, no parity.

				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry