HP 4 FAMILY - Manual (Page 115)

Alphanumeric ID
Command
The Alphanumeric ID command performs several different
functions depending on the operation specified. This
command:
Specifies the type of print media on which to print a job
(rather than specifying its location)
Specifies an ID string for different PCL objects (fonts and
macros)
Supports the mass storage PCL enhancements for the
LaserJet 5Si/5SiMx printer disk (allowing, for example,
downloading a font with a String ID to RAM— download-
ing to the printer disk must be done using PJL)
The format of the Alphanumeric ID command is as follows:
?&n#W[Operation][String ID]
# = Number of bytes of String ID data
Default = 0
Range = 2 to 512
The value field (#) identifies the number of bytes in the
String ID.
The Operation byte determines the type of operation and
the type of object on which the operation is to be performed.
The operations are listed in the table below.
The String ID begins with the second byte and can be up to
511 characters long.
Printer-Specific Differences 2-79