🚀 go-pugleaf

We have a HP Laserjet IIIP mounted on our Sun SPARCStation
(on /dev/ttya), with postscript emulation provided via a
Pacific Page P.E. cartridge. Since the printer can only 
operate in PCL or Postscript but not both, we have sought
to incorporate a filter in our /etc/printcap which will
determine the document type, and send an escape sequence
to switch the printer into the appropriate mode. This we
have achieved .... except for an infuriating problem which
occurs when going from postscript to PCL. Our input filter
having determined the document type, executes one of the 
following shells:

PCL to Postscript:

#!/bin/sh

echo ["^[&l5257.1058J^M"]     # Send escape sequence
sleep 40                      # Wait for printer to reset
cat

Postscript to PCL:

#!/bin/sh

echo ["^[&l1057.32259J^M"]    # Send escape sequence
sleep 40                      # Wait for printer to reset
cat                           # Send print file to printer


The first of these shells works fine. It is the second one
which causes the problems. Upon sending the escape sequence
the shell sleeps for 40 seconds while the printer resets.
When the printer resets however, it seems to receive extra
characters, even though the shell is supposedly still 
inactive. When the 'sleep 40' finishes, and the document
itself is passed to the printer, the following error 
appears at the top of the first page:

%%[ Error: undefined; OffendingCommand: %%
[

In addition, if I remove the 'sleep 40' AND 'cat' lines
from the shell (i.e. only send the escape sequence) the
reset works fine, with no extra data being sent to the 
printer. 
Is the problem due to an open ttya line sending signals
even while the controlling process is "asleep". We've 
tried everything and can't solve the problem....which
is even more annoying becauses it is so close to actually
working! If anyone reading this has any ideas or suggestions
which might help I would be eternally grateful. Is there enen
even an alternative to the method we're using. Any and all
replies appreciated.....Thanks to all in advance. My E-Mail
addresses follow....

CBRADH89@IRLEARN.UCD.IE
BRADSHAW@CCVAX.UCD.IE