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Processor Technology -   VDM-1
This was the first practical teletype like video board for the S-100 bus.  It was later replaced by the better Solid State Music board and later still by others that incorporated LSI chips on the board along with a keyboard input connection.

Processor Technology VDM-1    

While it worked it was not a clean PC board layout. There was an "embarrassing" ribbon cable connection from one side of the board to the other. Composite video came out via a connector at the top left hand corner of the board.
The VDM-1 generated sixteen 64 character lines from data stored in a 1024 8-bit byte on-card RAM memory.  Alphanumeric and control characters (the full 128 upper and lower case plus control ASCII character set) were displayed in a 7 x 9 dot matrix.  With its EIA video output, the VDM-1 could be used with any standard video monitor.  (A TV set could be easily modified for use with the VDM-1).
Two-port memory permitted random read-write access to the screen memory from the memory bus of the CPU.  Other features included:
The manual for this board can be obtained here


Other Processor Technology S-100 Boards
4K RAM   8K RAM   48K RAM    16K Dynamic RAM    1702 EPROM     3P+S    CUTS    GPM   VDM-1    Helios-II FDC


This page was last modified on 10/25/2013