Postwar American Television
Zenith had experimented with pay television as early as 1931. By 1947 they had a working system and in 1951 they introduced Phonevision. After receiving FCC approval, they began a 90 day test run with 300 families from the Lakeview-Lincoln Park area in Chicago. More information on Phonevision can be found at the Chicago Television History site.
Popular Mechanics, October 1947
Popular Science, October 1947
The following is from a 1954 Zenith publication The Zenith Story
Courtesy of Al Anderson
Zenith equipped some of its 1951 model sets with a connector for Phonevision. Below are pages from a Zenith owners manual.
From the 1953 Zenith Corp. Annual Report
Courtesy of Larry Auman