On Wed, 25 May 2005, Jean-Michel Barbet wrote:

> - many PPDs for the most common printers are part of the cups-drivers
>   RPM and one of these is selected when you add/modify printer.
>   They are in :
>   /usr/share/cups/model/foomatic/
>   The one we use is :
>   HP/HP-LaserJet_5M-Postscript-cups.ppd.gz

OK.  Our printer was a new model and did not have a stock PPD file 
there.

> - I belive that when you "configure" a specific printer named
>   "myprinter", a specific PPD is created using the above PPD as
>   a template and adding the specific configuration options.
> 
>   This generated PPD is :
>   /etc/cups/ppd/myprinter.ppd

Ah, I understand you now - in fact a "myprinter.ppd" file is created 
there for each PPD-based printing queue, and I suppose you're right 
that this is modified when the Configure Printer menu is used.

> Anyway, in /etc/cups/ppd/myprinter.ppd, I have the following :
> 
> *OpenUI *Duplex/Double-Sided Printing: PickOne
> *DefaultDuplex: None
> *Duplex DuplexNoTumble/Long Edge (Standard): ""
> *Duplex DuplexTumble/Short Edge (Flip): ""
> *Duplex None/Off: ""
> *CloseUI: *Duplex

It's not clear to me whether this is telling the server that your 
printer has double-sided capability or not.  The "Configure Printer" 
web page on the server *should* offer the ability to tailor this, if 
it's working the way that our Kyo PPD file does.  If the driver does 
not believe that the printer has this capability, I don't think it 
will honour requests to use it.

If the PPD does not make provision for configuring this via the 
configure-printer interface, then I suppose you may need to edit the 
PPD file by hand.  I can't really advise on what the correct settings 
would be, though.  In its PPD file, the Kyo calls this "Option16", and 
the optional paper tray is "Option20", which are clearly specific to 
the Kyo.