Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uunet!intercon!news
From: amanda@mermaid.intercon.com (Amanda Walker)
Newsgroups: comp.lang.postscript
Subject: Re: 9600 bps bottleneck on Laserwriter Plus
Message-ID: <1700@intercon.com>
Date: 10 Jan 90 00:04:25 GMT
References: <3495@hub.UUCP>
Sender: news@intercon.com
Reply-To: amanda@mermaid.intercon.com (Amanda Walker)
Organization: InterCon Systems Corporation
Lines: 35

In article <3495@hub.UUCP>, jim@cavevax.ucsb.edu (Oreo Cat) writes:
> The serial port on the host computer can be driven at up to
> 38400 bps, but unfortunatley the serial port on the LW+ only goes up to
> 9600.  I am told that the appletalk connection runs at something like
> 64 kbps.

Well, it runs at about 240kbps in AppleTalk mode, but that isn't useful
in your situation unles your host understands AppleTalk network protocols.
The standard switch settings only let you ask for up to 9600 baud, but the
printer will operate faster.  It will receive data at up to 57600 baud,
or maintain reliable bidirectional communication at up to 19200 baud.
I haven't ever tried to run it at 38400, but there shouldn't be any problem.

The PostScript operators 'setsccbatch' and 'setsccinteractive' (described
in the LaserWriter supplement in the back of many editions of the Red Book)
control baud rates.  Here is some code that I believe should set your printer
to 38400 baud, but since I run over AppleTalk exclusively, I haven't
tested it--Woody will probably set me straight if I've made a goof here
:-):

	statusdict begin
	25 38400 0 setsccbatch
	end

This should change the '9600' switch setting to actually select 38400 baud.
The baud rate is actually changed at the end of the current job, and should
be persistent across power cycles unless a stray lightning bolt zaps the
EEPROM in your printer :-).

Hope this helps,

Amanda Walker
Speaker to PostScript
InterCon Systems Corporation
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