HP PCL/PJL reference - Printer Job Language Technical Reference Manual

7-18 Status Readback Commands EN
Variables appear in the response only if they are installed in the
printer. For example, if a HP LaserJet 4 printer does not have the
lower paper cassette installed, the INTRAY3 option is not returned in
the response.
The general format of the returned information is:
The returned information can list multiple features, with the format of
the feature information enclosed in brackets. For “[ <value> feature
information]”, the square brackets ( [ ] ) in the format indicate an
optional item as well as indicating that brackets enclose the feature
information. For example, [4 ENUMERATED] indicates there are 4
returned options for the feature. Refer to the sample printer response
in the “Using the INFO CONFIG Command” example for the format of
an actual response.
@PJL INFO CONFIG<CR><LF>
feature[=value][<value> feature information]<CR><LF>
[<HT>returned option[ attribute]<CR><LF>]
. . .
. . .
feature[=value][<value> feature information]<CR><LF>
[<HT>returned option[ attribute]<CR><LF>]
<FF>