Plantronics Colorplus Explained

Plantronics Colorplus
Designfirm:	Frederick Electronics
Manufacturer:	Plantronics Enhanced Graphics Products
Entry:	Plantronics Colorplus
Highend:	ATI Graphics Solution, Paradise AutoSwitch EGA 480
Predecessor:	CGA
Successor:	EGA
Architecture:	Motorola MC6845

The Plantronics Colorplus is a graphics card for IBM PC computers, first sold in 1982. It implements a superset of the then-current CGA standard, using the same monitor standard (4-bit digital TTL RGBI monitor) and providing the same pixel resolutions.^[1] It was produced by Frederick Electronics (of Frederick, Maryland), a subsidiary of Plantronics since 1968, and sold by Plantronics' Enhanced Graphics Products division.^{[2] [3]}

The Colorplus has twice the memory of a standard CGA board (32k, compared to 16k). The additional memory can be used in graphics modes to double the color depth, giving two additional graphics modes—16 colors at resolution, or 4 colors at resolution.^[4]

It uses the same Motorola MC6845 display controller as the previous MDA and CGA adapters.

The original card also includes a parallel printer port.

Output capabilities

CGA compatible modes:

• 16 color mode (actual a text mode using , ▌, ▐ and █)
• in 4 colors from a 16 color hardware palette. Pixel aspect ratio of 1:1.2.
• in 2 colors. Pixel aspect ratio of 1:2.4
• with pixel font text mode (effective resolution of)
• with pixel font text mode (effective resolution of)

In addition to the CGA modes, it offers:

• with 16 colors
• with 4 colors
• "New high-resolution" text font, selectable by hardware jumper

The "new" font was actually the unused "thin" font already present in the IBM CGA ROMs, with 1-pixel wide vertical strokes. This offered greater clarity on RGB monitors, versus the default "thick" / 2-pixel font more suitable for output to composite monitors and over RF to televisions but, contrary to Plantronics' advertising claims, was drawn at the same pixel resolution.

Software support

Few software made use of the enhanced Plantronics modes, for which there was no BIOS support.

A 1984 advertisement^[2] listed the following software as compatible:

• Color-It
• UCSD P-system
• Peachtree Graphics Language
• Business Graphics System^[5]
• Graph Power
• The Draftsman
• Videogram
• Stock View
• GSX
• CompuShow (mode)^[6]

Some contemporary software has added support for Plantronics modes:

• Planet X3, released by American YouTuber David "The 8-Bit Guy" Murray in 2019, was the first video game known to have Colorplus support (with 16 colors). This support was added by Planet X3 enthusiast Benedikt Freisen.^[7]
• Attack of the Petscii Robots by American YouTuber David "The 8-Bit Guy" in 2020, ported to MS-DOS computers with a graphics mode providing support for Plantronics Plus.
• Benedikt Freisen produced updated drivers in 2021 that add Colorplus support to Sierra's adventure games that ran on Sierra's Creative Interpreter.
• FastDoom, a port of Doom (1993 video game) developed by Victor Nieto, added support for ColorPlus with 16 colors mode in 2021.^[8]

Hardware clones

Some third-party CGA and EGA clones, such as the ATI Graphics Solution and the Paradise AutoSwitch EGA 480,^[9] could emulate the extra modes (usually describing them simply as 'Plantronics mode').

The Thomson TO16 (a PC-XT compatible)^[10] and the Olivetti M19 supported Plantronics modes,^[11] along with CGA.

See also

• Tandy Graphics Adapter, a graphics hardware system with similar capabilities.
• Quadram Quadcolor
• Orchid Graphics Adapter
• Hercules Graphics Card
• Olivetti M19
• Thomson TO16

External links

• "+COLORPLUS Shatters The Mold.", an original advertisement.
• A USENET posting describing the Plantronics Colorplus
• The technical documentation for the Paradise EGA chipset in the Amstrad PC-1640 describes its Plantronics compatibility mode.

Notes and References

1. News: Machrone . Bill . July 1983 . Three Alternative Graphics Boards . 435–438 . PC Magazine .
2. Book: Colorplus High Resolution Color Graphics Adapter from Plantronics . 1984 . Frederick Electronics . English.
3. Staff writer . July 1, 1975 . Modern industries heart of area economy . The News . Frederick, Maryland . 4, 8 . Newspapers.com.
4. Web site: Elliott . John . March 28, 2015 . Plantronics ColorPlus Notes . 2023-04-17 . John Elliott's homepage.
5. News: June 11, 1985 . Business Graphics System . 4 . 203 . PC Magazine . 12 .
6. Web site: Berry . Bob . 1993 . CompuShow v8.60 Documentation . cd.textfiles.com . Canyon State Systems.
7. Web site: Murray . David . Planet X3 is Here! And with new video modes! . The 8-Bit Guy . 19 February 2019 . 6 September 2019.
8. Web site: Nieto . Victor . Aug 16, 2021 . FastDoom 0.8.7 release notes . 18 November 2022 . FastDoom at GitHub.com.
9. News: Hart . Glenn . December 22, 1987 . EGA Plus Cards: VGA res for EGA monitors . 218 . PC Magazine .
10. Web site: 2007 . Ordinateur : Le Thomson TO16 XP HD . Association MO5.COM . fr.
11. Book: Caratteristiche techniche Personal Computer M19 . March 1986 . Olivetti . Italian.