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From: cramer@kontron.UUCP (Clayton Cramer)
Newsgroups: net.micro.mac,net.micro.pc
Subject: Re: LaserWriter+ <--> IBM-PC
Message-ID: <1128@kontron.UUCP>
Date: Mon, 13-Oct-86 13:12:32 EDT
Article-I.D.: kontron.1128
Posted: Mon Oct 13 13:12:32 1986
Date-Received: Tue, 14-Oct-86 06:27:22 EDT
References: <544@water.UUCP> <591@bunny.UUCP> <818@gould9.UUCP>
Distribution: net
Organization: Kontron Electronics, Mt. View, CA
Lines: 64
Xref: watmath net.micro.mac:8286 net.micro.pc:10421

> In article <591@bunny.UUCP>, mdf0@bunny.UUCP (Mark Feblowitz) writes:
> > My Apple dealer gave me the following pinouts, which still don't
> > seem to solve a problem that I've had with Laserwriter buffer overruns.
> 
> The LW uses X-on/X-off.  A standard unadorned IBM PC BIOS serial driver,
> I believe, ignores X-off.  At least, this is the way the problem was
> explained to me.
> -- 
> 	Joel West			     MCI Mail: 282-8879

LaserWriter release 2.0 and all LaserWriter Plus systems default to
XON/XOFF.  You can run them with RTS/CTS, which will solve the buffer
overrun problem with your PC.  The following piece of code comes from
Matt Foley at Adobe Systems (the authors of PostScript).

] To switch to DTR flow control, you must give a special instruction 
] to the printer.  This instruction must be given ONCE.  It writes into 
] an EEPROM, and thus its effect remains over power cycles.
] 
] The easiest thing is to create a small text file containing the
] following code:
] 
] 	serverdict begin  0 exitserver
] 	statusdict begin
] 	25 9600 4 setsccbatch
] 	end
] 	^D
] 
] Comments:
] The '0' before 'exitserver' is a password.  This may be changed by the
] system manager, but 0 is the default.
] The verb 'setsccbatch' requires three arguments.  The first may be 9 or
] 25, indicating which hardware port you are using.  The second may be
] any of a broad selection of reasonable baud rates, including 9600,
] 19200, and 57600.  The third is an option parameter.  0-3 use XON/XOFF
] flow control, 4-7 use DTR flow control.  0 or 4 are 8-bit words, 7 bits
] data, parity bit ignored; 1 or 5 are odd parity; 2 or 6 are even
] parity; 3 or 7 are 8-bit valid data, no parity.
] (The 3 or 7 options do NOT give a fully transparent channel, as
] ^D,^C,^T,CR,LF and [with XON/XOFF] ^S,^Q remain "special characters"
] that are trapped by the serial driver.)
] 
] The ^D at the end of the file is very important, as, having used
] 'exitserver', you must restart the printer's server loop by terminating
] the current job.  You can terminate the job either by sending a CTRL-D
] (hex 04) to the printer, or by waiting 30+ seconds for a timeout to
] occur.
] 
] Finally, the changes will not take effect until the next time you
] power-cycle the printer.
] 
] Since this PS program is very short, you will have no difficulty
] sending it to the printer with the DOS print command.
] 
] All this and more are in the "PostScript Language Update for the Apple
] LaserWriter Revision 2 and LaserWriter Plus".  This adds to the info in
] "PostScript Language Supplement for the Apple LaserWriter", and should
] be in current versions of Apple's "Inside LaserWriter".  At any rate,
] it is available from Apple.
] 

Hope this cross-fertilization of groups helps.

Clayton E. Cramer