ptok@void.caltech.edu (phillip tokumaru) (04/27/91)
Keywords: HP, LaserJet
Reply-To: ptok@void.caltech.edu
1) Next and HP don't agree on the RS-232 standard. Here's the correct ``null
modem'' cable. Don't use the one from NeXT because you will lose data and get
all sorts of errors. This is because the HP sets the RTS(4) pin whenever it's
powered up. The Next thinks this means it's always ready for data. Instead,
the HP sets the DTR(20) pin whenever it's ready for data. The Next basically
ignores this for /dev/ttya,b and /dev/ttyfa,b. (It's basically the same as
Next's with the 4 and 20 pins reversed on the DB-25 side). I only discovered
this discrepancy after reading both the Next's and the HP's handshaking
descriptions, many times. If I learned anything it's: Never, Never, Never,
take a ``standard'' for granted!
NeXT 68040 to HP LaserJet III Cable (not a Null-modem cable):
Mini-Din HP DB-25
1 (DTR) nc
2 (DCD) 4 (RTS)
3 (TXD) 3 (RXD)
4 (GND) 7 (GND)
5 (RXD) 2 (TXD)
6 (RTS) 5 (CTS)
7 (RTXC) nc
8 (CTS) 20 (DTR)
2) Use hardware flow control for reliability, i.e., /dev/ttyfa for serial port
a and /dev/ttyfb for serial port b (What I'd really like is a /dev/appletalk,
then I could get up to 230kb)
Next and printer configurations follow:
My printcap from my ni database: (note that 19.2kb work just fine)
LaserJet_III: \
:note=LaserJet_III:ty=HP LaserJet III PostScript: \
:sd=/usr/spool/NeXT/LaserJet_III:lp=/dev/ttyfa: \
:lf=/usr/adm/lpd-errs:af=/usr/adm/lp.acct:br=19200:rw:fc#0000374: \
:fs#0000003:xc#0:xs#0040040:mx#0:sf:sb:if=/usr/lib/transcript/psif: \
:of=/usr/lib/transcript/psof:gf=/usr/lib/transcript/psgf: \
:nf=/usr/lib/transcript/psnf:tf=/usr/lib/transcript/pstf: \
:rf=/usr/lib/transcript/psrf:vf=/usr/lib/transcript/psvf: \
:cf=/usr/lib/transcript/pscf:df=/usr/lib/transcript/psdf:
HP printer configuration:
auto cont = off (doesn't matter)
I/O = serial
serial=rs-232
baud rate = 19200 (same as in ni database/ printcap)
robust xon = on (doesn't matter)
dtr polarity = hi
startpage = off (doesn't matter)
language=english
ret = med (you choose)
About the printer: After downloading the fonts, it prints up to it's rated
speed (7-8ppm) for text and simple graphics. Because of it's pea (68000) brain,
complex ps graphics take longer. The consolation you get is that there is
virtually no performance hit on the Next.
Except for very thin lines, the resolution enhancement looks as good as the
Next's 400 dpi. In addition, the quality of construction is typical HP, high.