IBM Personal System/55

Display Adapter II

Screenshot of MIFES (text editor) in character mode

Similar to IBM 5550, the character mode is 1040×725 pixels (12×24 and 24×24 pixel Mincho font, 80×25 characters) in 8 colors. It can display Japanese characters read from a font ROM on the video card. The graphics mode is 1024×768 pixels in 16 colors. This is the same resolution as 8514/A and XGA/A, but not compatible. These modes are implemented in an MCA video card called Display Adapter, and installed in the system unit.

The first Display Adapter was installed in the model 5570-S, also known as the first Micro Channel machine of PS/55. It had a compatibility problem with PS/2 softwares. Since the model 5550-S released in 1988, the Display Adapter II that improved the PS/2 compatibility was introduced. In the boot sequence, the Display Adapter enables VGA on the motherboard, and the video signal is output for the Display Adapter through an MCA connector. When using Japanese DOS, VGA is disabled, and the Display Adapter switches its video selector from VGA to own video chip. In addition, it added the 256 color mode (1024×768 pixels in 256 colors chosen from 262,144 colors).

Most models have compatibility with the Display Adapter II. VGA and the following display modes are supported:

• 1040×725 pixels with 80x25 characters in 8 colors or monochrome
• 1024×768 pixels graphics in 16 colors or monochrome
• 1024×768 pixels graphics in 256 of 262,144 colors

Later, XGA and VGA-only models were released. These machines cannot run the Japanese DOS. Instead it required DOS/V.

5576-002 Keyboard

The following keyboards have the PS/2 port. These keyboards have new scancode sets (81h, 82h, 8Ah) to support additional keys for Japanese input.

• 5576-001 - Same layout as 5550 type 1 (5556-001) keyboard.
• 5576-002 - Japanese layout based on 101 Enhanced keyboard, but uses Alps Electric Co. mechanical key switches.
• 5576-003 - Space-saving version of 5576-002
• 5576-A01 - OADG reference keyboard.[2]