lpr filter design question

[Richard Steinberger]

I have a DEC LN03+ laser printer that I would like to connect to the serial
port of a DEC3100 or a Multiflow.  The printer needs to be sent a set of
control characters as an initialization string before each job.  The
particular string sent determines whether the printer enters its Tektronix
mode, portrait mode, landscape mode, selects a font, defines TAB stops, and
some other things, as appropriate.

What I would like to do is put the set of escape strings in a text file
as follows:

LABEL1:<ESC>a<ESC>b23;
LABEL2:<ESC>b<ESC>b34;
LABEL3:....
LABEL4:....

where <ESC> is the escape character, and the above are just examples.
The filter program would receive an argument specifying the LABEL, then
send out the string to the right of the label's colon, followed by the
byte stream from the file.  

My question:  Is this a possible or reasonable approach? If so, how
would lpr pass the LABEL arguments to the filter program?  
Should the filter send output to stdout, or elsewhere?  Is there
a particular manual/document that has more details on this?  The above
scheme seems like it ought to be extensible to many brands of printers.
Has anyone developed anything like this; is there another approach I 
should consider; or are printer filters best left to "experts"?

thanks for any help/suggestions.  Please reply to me directly, as
I am not a regular reader of this bboard.

regards,

	ric steinberger
	ric at ace.sri.com
	ric at rml2.sri.com

	(415) 859 - 4300