What does this PS code mean ?

[george@mech.seas.upenn.edu ( George Jefferson )]

:        % faxmail prologue file.
:        %
:        /EPSbegin{save gsave 20 20 scale 200 dict begin}def
:        /EPSend{end grestore restore}def

those two lines are defining procedures. You may see somewhere
later in the file,

EPSbegin
bla bla bla
EPSend

Its quite possable they arent used at all..
It is basically setting up an environment, so that whatever the
included code is (bla bla) it cant mess up the rest of the document
too bad.

If you are adding your own code, it wouldn't hurt to
wrap it in EPSbegin ... EPSend although if its simple
code I'd just do gsave ... grestore