HP 4 FAMILY - Manual (Page 12)

Notes In Table 1-1, if the command value field parameters are
not listed, then all parameters are supported by printers
that support that command.
The value in parentheses following a command
parameter identifies the parameter value field value (for
example, the parameter “Letter (2)” indicates that the
value field to select letter size in the Page Size command
is “2” ).
Commands which are not supported (“ns”) by a printer
are ignored.
1-4 Feature Set