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From: cmilono@wet.UUCP (Carlo Milono)
Newsgroups: comp.sys.hp
Subject: Re: HP7550a
Keywords: Plotter
Message-ID: <1555@wet.UUCP>
Date: 21 Sep 90 01:01:52 GMT
References: <2518@dsacg3.dsac.dla.mil>
Reply-To: cmilono@wet.UUCP (Carlo Milono)
Distribution: usa
Organization: Wetware Diversions, San Francisco
Lines: 15

I have had troubles with HP Plotters under DOS!  There are special cables 
required as per your manual that should have come with the plotter.  You
will need to make a special cable if you do *not* already have one.

Secondly, you must realize that you will need to decide if you require 
hardware flow control, or only xon/xoff and then, since the older 3B
ports only used software control, you will most likely need to pace the
port at the appropriate speed to avoid buffer skid.

Thirdly, all the above must be coordinated as if you were setting up
a printer with the appropriate line printer 'stty' interface parameters
corresponding to the HP's settings.  Since you stated that you saw the
RD light flickering, I would wager that data is being sent - I hope you
don't send a banner page :-)!  That being the case, I would look to
problems with parity and speed in your interface script.