Page "Digital video" Paragraph 3

Later on in the 1970s, manufacturers of professional video broadcast equipment, such as Bosch ( through their Fernseh division ), RCA, and Ampex developed prototype digital videotape recorders ( VTR ) in their research and development labs.

Bosch's machine used a modified 1 " Type B transport, and recorded an early form of CCIR 601 digital video.

None of these machines from these manufacturers were ever marketed commercially, however.