XON/XOFF flow control on LaserWriter+?

[keith gorlen]

I'm trying to connect an Apple LaserWriter+ to a serial port (/dev/ttya)
on a Sun-3/50 running SunOS 3.5 and Adobe TranScript 2.1.  The printer is
cabled to the 3/50 as a 3-wire null modem: pin 2 to pin 3, pin 3 to pin 2,
and pin 7 to pin 7.  The LaserWriter+ is set for 9600 baud.  Here is the
/etc/printcap entry:

# local PostScript printer driven by TranScript software
lp|applejuice|lsmlaser|ps|postscript|PostScript:\
	:lp=/dev/ttya:sd=/usr/spool/lpd:\
	:lf=/usr/adm/lsmlaser-log:af=/usr/adm/lsmlaser.acct:\
	:br#9600:rw:fc#0000374:fs#0000003:xc#0:xs#0040040:\
	:mx#0:sf:sb:\
	:if=/usr/lib/ps/psif:\
	:of=/usr/lib/ps/psof:gf=/usr/lib/ps/psgf:\
	:nf=/usr/lib/ps/psnf:tf=/usr/lib/ps/pstf:\
	:rf=/usr/lib/ps/psrf:vf=/usr/lib/ps/psvf:\
	:cf=/usr/lib/ps/pscf:df=/usr/lib/ps/psdf:

The printer doesn't work properly; specifically, a short job prints OK,
but a longer job gets flushed after a page or two with a postscript
ioerror.  The LaserWriter+ does not seem to be sending XON/XOFF for flow
control, but toggling DTR instead.

Is there some magic postscript command I need to send to the LaserWriter+
to enable XON/XOFF, or some switch setting internal to the printer that is
not correctly configured?  Any help would be greatly appreciated.  Thanks.

	Keith Gorlen			phone: (301) 496-5363
	Building 12A, Room 2017		uucp: uunet!nih-csl!keith
	National Institutes of Health	Internet: keith at alw.nih.gov
	Bethesda, MD 20892