To provide a free-form format that allows the transmission of text information
Free-form message text
A field to be used for the control of the line feed of the receiving printer
MSG02 is not related to the specific characteristics of a printer, but identifies top of page, advance a line, etc.
A generic number
MSG03 is the number of lines to advance before printing.
If MSG02 is "AA - Advance the specified number of lines before print" then MSG03 is required.