PRESERVING THE HISTORY OF THE RADIO SHACK VIDEOTEX & ALL THINGS RELATED
Project Green Thumb was an "experimental videotext project" by the Kentucky Cooperative Extension Service and the University of Kentucky College of Agriculture" in 1980.
Motorola Semiconductor of Austin, Texas, won the contract for the user terminals and Tandy's Computer Division joined later to manufacture the terminals.
The initial goal of this project was to create a low cost Videotex terminal for farmers, ranchers, and others in the agricultural industry. This terminal would connect to a phone line and an ordinary color television and allow the user access to near-real-time information useful to their day-to-day operations on the farm.
Motorola's MC6847 Video Display Generator (VDG) chip was released about the time the joint venture started. The 1978 prototype "Green Thumb" terminal used the MC3870 microprocessor.
NEW!
We recently acquired an original schematic (Revision 0.0) of the "Motorola Information Terminal" - which would become the Green Thumb Box. It was also confirmed, through the schematic and actually opening up the Green Thumb Box, that the processor is not a 680x but in fact the MC3870.
Therefore - while the GTB is a predecessor to the Videotex and Color Computer, it is not a 1:1 design port.