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From: achille@cernvax.UUCP (achille petrilli)
Newsgroups: comp.lang.postscript
Subject: Re: 9600 bps bottleneck on Laserwriter Plus
Message-ID: <1200@cernvax.UUCP>
Date: 11 Jan 90 00:12:01 GMT
References: <3495@hub.UUCP> <1990Jan10.042555.19571@grian.cps.altadena.ca.us>
Reply-To: achille@cernvax.UUCP (achille petrilli)
Organization: CERN European Laboratory for Particle Physics, CH-1211 Geneva, Switzerland
Lines: 40

In article <1990Jan10.042555.19571@grian.cps.altadena.ca.us> alex@grian.cps.altadena.ca.us (Alex Pournelle) writes:
>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.  Is there any way of connecting this to a serial port?  Or is
>>there any way of making the serial port run faster than 9600?
>>  It now looks like we'll be printing more of the bitmaps, so any
>>cheap solutions to this problem would be greatly appreciated!
>
>Implement a postscript decompresso program--one that "unsqueezes" data
>as it comes through the pipe--download it to the printer, then do the
>reverse on the computer.  With some simple escapes, you could massively
>increase throughput on nearly any large file.
>
>Comments?
>	
>		Alex

Comments ? yes. Look for a simpler solution.
Actually both the LaserWriter plus and the NT (so I guess the NTX as well)
can run up to 38Kbaud, it's my Apollo that can't run at more than 19Kbaud !
Look in the Appendix of the Red Book, where the laserwriter dependent
commands are, and download a PS program to permanently change the speed.

I don't have the book handy now, but I seem to remember that 19K and 38K
are not documented, just extrapolate from the command that changes the 
speed what 19k or 38k should look like and run it.

By the way you can change independently the speed on the 25 pin port and
on the 9 pin port. I'd recommend that you set one of them to 9600 baud
before, then you test it, and when you're sure everything works, you reset
the other to 38k. This insures that you can still talk to the printer
even if you do a mistake.

Hope this helps,

	Achille Petrilli
	Cray & PWS operations