It is a Multi I/O card with Monochrome/CGA output. It currently drives my IBM 5151 and IBM 5153 monitors.
From the manual:
What is a Graphix Plus II?
The STB GRAPHIX PLUS II is a universal video adapter board for the IBM Personal Computer, the IBM Personal Computer model XT, the IBM Portable Personal Computer and most IBM hardware compatible computers. The STB GRAPHIX PLUS II is used to connect the computer to a variety of video display monitors and printers. The board also contains provisions for an optional battery operated time-of-day clock/calendar.
Features
• Supports botb RGB color and monochrome displays on a single STB GRAPHIX PLUS II. Automatically switches display to the appropriate monitor.
• Configurable as a Color Graphics and/or a Monochrome/Printer Adapter. Hardware and software compatible with the IBM display adapters.
• Flicker free scrolling in all display modes. No snow on picture when screen RAM is accessed, allows high speed screen updates and scrolling.
• 32Kb of display RAM available in all text and graphics modes.
• Supports high resolution display modes with appropriate software drivers:
320 X 200 X 16 color grapbics
640 X 200 X 4 color grnpbics
640 X 350 monochrome graphics
8O X 44 monochrone text
• Parallel printer port is standard. Port is switchable between "Centronics" style printer interface or SASI/SCSI hard disk controller interface.
• User-installable battery operated time-of-day clock/calendar option.
• Can be used with a second display adapter card for simultaneous display of text and graphics on two monitors.
• Customizable video monitor driver chip allows use with most standard video monitors. Customized versions for special monitors are available.
• Supports graphics on many monochrome text display monitors without special software drivers.
• True grey scale display on composite video monitors. Does not support composite color displays.
• Includes PC Accelerator printer buffer and electronic RAM disk utility program. Supports up to two 360Kb "disk drives" and a 64Kb printer buffer.
