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- From: vulture@imperial.ac.uk (Thomas Sippel - Dau)
- Newsgroups: comp.sys.sgi
- Subject: Re: Printer Parallel port misery
- Message-ID: <1992Nov18.162359.11122@cc.ic.ac.uk>
- Date: 18 Nov 92 16:23:59 GMT
- References: <1992Nov16.131533.16209@eurohub.neu.sgi.com> <1992Nov16.141604.16853@eurohub.neu.sgi.com>
- Sender: vulture@carrion.cc.ic.ac.uk (Thomas Sippel - Dau)
- Reply-To: cmaae47@imperial.ac.uk
- Organization: Imperial College of Science, Technology and Medicine
- Lines: 40
- Nntp-Posting-Host: cscgc
-
- In article <1992Nov16.141604.16853@eurohub.neu.sgi.com>, joe@spectrum.neu.sgi.com (Joe Elliott) writes:
- - I have been having problems with printers for some time now. All of them
- - with PostScript printers and parallel ports.
- - Things are great for small print jobs but given a reasonable load, the port
- - just stops and the jobs keep queueing up.
- ......
- - Maybe a comms problem as it only happens on large jobs when the job
- - possibly exceed the printers memory capacity,Handshaking maybe Xon/Xoff not
- - stopping the data flow.
-
- Cannot really be Xon/Xoff, as the normal Centronics printer protocol is
- simplex - i.e. printer cannot drive port, so cannot send (ascii text) information
- back to the computer. PostScript printers sometimes give you messages.
-
- You could try to get a line analyser for parallel ports whic show you the
- state of the lines - unfortunately most serial port testers will probably not
- work, unless they have a LED and mandatory jumper lead for each of the 25
- pins.
-
- Check if you get status changes on the pins 1 and 10 of the 25 pin connectors,
- the Indigo should flip the state of line 1 for every byte twice to strobe
- out the data, the printer should respond on pin 10 to say it got the byte.
- Thus flow control should be automagic, but ...
-
- Vernon told me once that there is a 15 second time-out on the parallel port,
- but that applied only if the port had been closed. But a PostCript printer
- may well be in think state for 15 seconds without anything untoward being
- the reason - I have somewhere a PostScript program of 17 lines or so that
- prints a Mandelbrot set and reputedly run for 48 hours (!) on a Laserwriter+
-
- Once you have decided which box is at fault, complain to the manufacturer :-).
-
- Thomas
-
- --
- *** This is the operative statement, all previous statements are inoperative.
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