Michael Dillon's NAPLPS document describes this standard this way:
"NAPLPS (North American Presentation Layer Protocol Syntax)
is a communications protocol that extends ASCII to allow for
the EFFICIENT transmission of picture and text information
over telecommunications channels such as modems. It does not
contain the commonly used ANSI protocol but it does include
similar capabilities and it could be used simultaneously
with ANSI although most NAPLPS terminal programs do not
currently support ANSI.
"A NAPLPS image is transmitted in a manner that is
independent of the resolution and color capabilities of the
receiving display. There are NAPLPS terminal programs
available for Amiga, Macintosh and PC's with CGA, Herc
monochrome, EGA, VGA and other display resolutions.
"This is accomplished by sending instructions to the
terminal program that tell it how to draw the required
pictures and text. Even bitmap pictures are transmitted in a
scalable fashion."