🚀 go-pugleaf

In article <ADMIN.91Jan23165838@exsg.cs.exeter.ac.uk> admin@cs.exeter.ac.uk (System Administrator) writes:

>We are experiencing some problems with the apollo (domain OS 10.2 bsd)
>serial port whilst attempting to drive a postscript laser printer.
>
>As far as we can determine the problem occurs when the postscript file
>has finished its job and the printer sends a Ctrl-d back to the
>computer.  At this point the computer echos two backspace's which the
>printer sees as errorneous postscript, ignores further input,
>timeouts, sends end of job (ctrl-d) to which the computer sends 2
>backspace's and the cycle continues.

Here's a possible workaround.  You can actually define a PostScript
"procedure" that has two backspaces as its name, and make the procedure
a no-op.  That should prevent triggering the PostScript error, in
any case.  I'm not sure whether you would want to define the name to
be a single backspace or to be two consecutive backspaces; I think
that two consecutive would be correct.

Try this:

%!
% (the "exitserver" line makes the patch stay until you power-cycle
% the printer, but it may not work exactly like this in your Apollo)

serverdict begin 0 exitserver

% define a string with two backspaces (octal \008) and use it as
% the name of a procedure:

(\008\008) {
    % do something to indicate that the procedure was actually
    % called.  If it works, delete this code:
    10 10 moveto
    /Times-Roman findfont 24 scalefont setfont
    (double-backspace handled) show
    showpage
} def


% I hope this helps,
% Glenn
-- 
 Glenn Reid				RightBrain Software
 glenn@heaven.woodside.ca.us		NeXT/PostScript developers
 ..{adobe,next}!heaven!glenn		415-851-1785 (fax 851-1470)