Not able to set default tray 2 printing on HP LaserJet 600 M602

Hi HP Printer Experts,

I am having difficulty on setting to default tray 2 on HP LaserJet 600 M602 printer from CUPS RedHat Enterprise Linux 6.7. All jobs would print automatically to the manual tray 1 (paper loaded) which does not need confirmation on printer.

I have no problem setup up CUPS printing on RedHat Enterprise Linux 6.7 but simply want to disable the automatic precedence of manual tray 1, that overwrites proper tray 2.

There are no setting to turn off / overwrite one tray over another.

I have spent many months including getting advice from CUPS Forum without success.

Many thanks in advance,

George