(I posted this summary last week and didn't see it show up. If you get
this twice, my apologies)
My original posting:
> I've got a HP LaserJet III w/ PostScript Cartridge hooked up to a Sun3/60
> running SunOS4.0.3 and Transcript 2.2. This is a replacement for an
> Apple LaserWriter NTXII. While a job is being printed, the "pscomm"
> program grabs all of the CPU and won't let go, bringing the machine to
> a complete standstill. The job *does* print. This is a dramatic change
> from when the LaserWriter was hooked up, as there was *no* visible impact
> on the system.
> All I've done is switch the HP for the LaserWriter (no software changes,
The problem turned out to be a *rather* substandard null-modem cable
between the Sun and the LaserJet. I dunno why the first one even worked
with the LaserWriter.
(for trivia buffs, here's what the original cable looked like:
2 ------- 3
3 ------- 2
6 ------- 6
7 ------- 7
20 ------- 20
A number of respondents mentioned the possibility of hardware handshakeing
problems. Also, luckily, John Goutsias <email@example.com>
posted a SUMMARY (<firstname.lastname@example.org>, thanks!) to
sun-managers today about his cabling problems with a HP LaserJet (with
a wiring diagram). After being connected to the LaserJet with a
properly wired null-modem cable, the Sun3 quite happily prints lots of
pages with the CPU meter down below 5%.
(for those who missed that SUMMARY, here's what the pin-outs looked
Null modem with full handshaking:
2 TxD ----------- RxD 3
3 RxD ----------- TxD 2
4 RTS ----------- CTS 5
5 CTS ----------- RTS 4
6 DSR -+--------- DTR 20
8 DCD -- -- DCD 8
20 DTR ---------+- DSR 6
7 GND ----------- GND 7
As for the second part of my query, regarding the meaning of "Robust X-ON"
and STARTPAGE, apparantly they *are* in the manual, just not the manual
shipped with the printer! One needs the LaserJet III Technical Reference
Manual (the User manual just won't cut it). here's an excerpt sent me by
I-Teh Hsieh <hsieh@crayfish.UCSD.EDU>:
>From page C-10 of the LaserJet III Technical Reference Manual
P/N 33449-90903, Robust X-ON, when set on, if no data is received
within approximately one second of the transmission of an Xon,
it allows additional Xon's to be transmitted at one second
intervals until data is received.
An Xon is transmitted when:
1. The I/O buffer has more than 64 empty bytes.
2. The printer is ON-LINE.
3. The printer is NOT BUSY.
An Xoff is transmitted when:
1. The I/O buffer has 64 or fewer bytes empty.
2. The printer is OFF-LINE.
3. The printer is BUSY.
If additional data bytes are received from the host after the
Xoff is transmitted, additional Xoff characters are transmitted
when the buffer has 32, 16, 8, 4, 2, 1, and 0 bytes empty.
STARTPAGE is a toggle governing the production of a test/summary
page when the machine is turned on (kinda obvious i guess).
Most of the respondents mentioned that they had turned Robust X-ON off
and relied only on hardware handshaking. Most had also pushed the
machine to 19200 baud.
I'd like to thank the following (in order of arrival) for replying to
my original message:
David Harnick-Shapiro <david@laguna.ICS.UCI.EDU>
John Benjamins <johnb@edge.CIS.McMaster.CA>
Lee Vrieze <email@example.com>
Steven E. Grevemeyer <firstname.lastname@example.org>
Matt Goheen <email@example.com>
I-Teh Hsieh <hsieh@crayfish.UCSD.EDU>
Vince Giambalvo <firstname.lastname@example.org>
Gerald Justice <email@example.com>
Frank F. Rizzo <firstname.lastname@example.org>
diab jerius university of michigan
internet: email@example.com department of astronomy
voice: (313) 764-3440 ann arbor, mi 48109
This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:06:19 CDT