The Processor Technology VDM-1 Video Board was a great improvement over teletypes and serial attached terminals back in the Altair glory days. It was one of the first memory mapped video boards that plugged directly into the S100 bus system. It produces a standard composite video output so it can be used with any monitor or TV set with video input jacks.

16 rows of 64 characters can be displayed simply by writing into the 1K of onboard memory. It supports normal or reverse video. Control characters can also be displayed if you like. Has a hardware scroll register so screen scrolling does not need to be done in software.

I tested this card on 05/09/99 and it works fine. Currently the video buffer is addressed at 0ec00h-0efffh, the IO control port is set to the default address of 0c8h. Both can easily be changed.

I built this card myself from a kit many years ago. The card is a Rev 0 and is copyright Processor Technology 1976. The serial number is 133349. The Assembly and Test Instructions manual is included.

If you'd like to see the original Processor Technology sales sheet for the VDM1, click on these links:

• Picture of the VDM-1 Caution this image is 116KB in size!
• Specifications Caution this image is 162KB in size!