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Path: utzoo!linus!philabs!seismo!harpo!eagle!allegra!alice!rabbit!rab
From: rab@rabbit.UUCP (Rick Becker)
Newsgroups: att.wanted,net.usoft.s
Subject: Re: How can I use my HP 7475A Plotter for S ?
Message-ID: <2316@rabbit.UUCP>
Date: Thu, 22-Dec-83 14:52:41 EST
Article-I.D.: rabbit.2316
Posted: Thu Dec 22 14:52:41 1983
Date-Received: Fri, 23-Dec-83 04:45:31 EST
References: <548@houxf.UUCP>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 20

You were right in using the "hpgl" device driver command in S
to work with the 7475 plotter.  The problem you have is in the
interface with the computer and terminal.

S supports Hewlett-Packard's HP-GL plotters in what is called 
"eavesdrop" mode -- the plotter is connected in series between
the modem and the terminal it is working with.
The plotter is configured to "normally off" position.
Whenever S wants to do graphics, it sends characters that
activate the plotter and do the picture.  S then de-activates
the plotter.  In the deactivated state, the plotter is transparent,
and lets characters pass in either direction between modem and terminal.

To use the eavesdrop mode for the 7475, you should have HP's
Y cable, Part 17455A, to make the serial connection.
(Or you can roll your own -- look in the "Interfacing and Programming
Manual" that came with the 7475.)
-- 

    Rick Becker  rabbit!rab