What is NAPLPS ?

North American Presentation Level Protocol Syntax

I was digging through my hard drive and found some old .txt files... and figured I'd publish them onto the web.

(from 1992)

NAPLPS is an acronym for North American Presentation Level Protocol Syntax.

...it's a pretty fancy title, but what does it mean?

Well, first of all, you can drop the "North American" part, that's where it started, NAPLPS is now an accepted standard around the globe -- more important is that it IS a STANDARD.

NAPLPS graphics encoding is covered by the 1983 ANSI X3.110 standard, under the heading, "Video-text/Tele-text Presentation Level Protocol Syntax", and is based on the International Standards, ISO-2022 and ISO-2375.

Yes, NAPLPS is ANSI!

The ANSI escape sequences which are the basis for the popular ANSI BBS terminal emulation, are very similar to NAPLPS escape sequences. Both can be communicated between two devices as ASCII data.

So, now we know NAPLPS is set of escape sequences which are standardized into ASCII data. Sounds simple, right? Well...sort of..

ANSI sequences (the kind that are used for color, attributes, cursor control, and terminal functions like screen clearing, and line feeds) are used in (80 column by 25 row) text mode, and thus "the hardware is made to conform to the data structure". What I mean by this, is that if a remote terminal wishes to use ANSI-BBS terminal emulation, the remote hardware is set to (80 x 25 char) text mode, regardless of the actual capability of the remote terminal's graphics hardware, (monitor/adapter). CGA, EGA, VGA, or SVGA all are reduced to text-type terminals, no graphics other than 80x25 IBM graphics characters are possible.

Even under MS-WINDOWS, or other GUI software, ANSI terminal emulation is reduced to a bit-map representation of an 80 x 25, text mode terminal screen.

NAPLPS does not make the remote terminal conform to the data structure. The data is "device independent". For now let's just say, "any graphic designed on one NAPLPS capable terminal can be viewed on ANY other NAPLPS capable terminal". This means a design created on a VGA equipped PC can be viewed on a monochrome, CGA, EGA, or other PC terminal, or on a MAC, or an AMIGA, or one of the many other computer types which NAPLPS decoders have been written for. And, it can be done during a ANSI text mode session.

To accomplish this, it necessary for the host system to "toggle" the remote user's terminal to and from NAPLPS and ANSI/text mode.

A NAPLPS decoder called MVDI is the heart of most NAPLPS capable applications in the market. MVDI, or "MicroStar's Virtual Device Interface" is invoked before a NAPLPS session begins. Using escape sequences, aware programs will route the NAPLPS encoded data through the MVDI decoder and translate the instructions into display graphics based on the MVDI-hardware device driver in use. Through this process, the host system, the remote terminal, and the NAPLPS data are all independent of each other.

The NAPLPS encoded graphic objects can be simple or complex, they can consist of scalable font text, lines, curves, circles, polygons, filled areas, and other "drawing primitives". You can use freehand point drawing to create any shape line or area. NAPLPS "blink" and "wait" capabilities, and the layering methods of most NAPLPS editors can be used to create animation for self running demos or tutorials.

Using advanced functions for fields and you can create data entry screens, and scrollable text windows. A process called "incremental point display" allows for the NAPLPS encoding of photographic and bit-mapped images.

At this point you may be thinking, "Why have I never heard of NAPLPS before", or "If it's so flexible, why isn't it in use" ?

You probably HAVE heard of NAPLPS, but it may have been called by another name. Video-text, Video Show, Online Graphics, these are just some of the terms used to described what is essentially NAPLPS.

Prodigy is the most wide spread application of NAPLPS, although most of the graphics on Prodigy are designed for CGA use and are not fully taking advantage of the standard. Another big name application, PageMaker, which
is the most popular professional desktop publishing package includes an "image import filter" for "Video Show Graphics", this makes it possible to incorporate high-resolution graphics captured from online (NAPLPS) sessions
into a printed document.

There are even utility programs for converting NAPLPS data to ham-radio packet message data. Version 2.0 of CorelDraw also has NAPLPS (Video Show) import/export capability.

Now we know that:

1. NAPLPS is covered by the ANSI X3.110 standard.
   
2. NAPLPS graphics can be created and displayed by nearly any type of computer hardware.
   
3. NAPLPS graphics can be reproduced on screen, in print, or transmitted from one device to another.
   
4. Many major software developers have incorporated NAPLPS support into their programs.