Phonevision

Phonevision

Company type	Pay television service
Industry	Television broadcasting
Founded	1951
Founder	Zenith Radio Company
Defunct	1969
Headquarters	Chicago , United States
Products	Pay television subscription service
Parent	Zenith Radio Company

Phonevision represented an initiative by the Zenith Radio Company to pioneer the first-ever pay television service worldwide. The system was initially developed and launched in Chicago, followed by pilot programs in New York City and Hartford, Connecticut.

History

Zenith's exploration of pay television dates back to 1931, driven by the belief that advertising revenue alone would not support television broadcasting sustainably. Initially, Zenith operated on television channel 1 in Chicago, starting February 2, 1939, with the station W9XZV. W9XZV was one of the earliest American stations to use electronic rather than mechanical technology and remained Chicago’s sole television outlet until October 1940. Later, Zenith's allocation moved to channel 2. In 1947, Zenith introduced a refined pay-TV technology under the brand "Phonevision." By 1950, the experimental broadcast shifted to the Field Building, adopting the call sign KS2XBS as it prepared for public demonstration.

In July 1953, KS2XBS ceased operations after the Federal Communications Commission reassigned channel 2 to WBBM-TV amid regional frequency reorganization. The KS2XBS transmitter was subsequently donated to Chicago’s inaugural educational station, PBS affiliate WTTW (channel 11).

Testing resumed in 1954 on New York City's WOR-TV (currently WWOR-TV), alongside contract negotiations in Australia and New Zealand. Additionally, broadcasts occurred briefly in Connecticut. Although Phonevision did not achieve widespread national adoption, it attracted considerable attention and promotional activity.

The service operated on station WHCT in Hartford, Connecticut, delivering standard programming during daytime hours and encrypted subscription content via Phonevision in the evenings for approximately five years until early 1968.

Phonevision concept

Phonevision’s model intended to provide feature films directly to viewers at home for a fee of $1 per movie (adjusted for inflation). Customers purchased a descrambler device that interfaced with both their television antenna and telephone line. To access content, subscribers called a Phonevision operator to enter a waiting list; once authorized, a signal transmitted through telephone lines unlocked the scrambled broadcast. Charges were billed monthly through telephone statements. Certain Zenith television sets from 1951 featured dedicated connectors and instructions designed specifically for Phonevision use.

While the Theatre Owners of America dismissed the service as unsuccessful, Zenith’s president Eugene F. McDonald asserted its effectiveness. Despite films being over two years old upon release via Phonevision, only 18% of viewers had previously seen them in theaters, and a significant 92% expressed a preference for viewing films at home.

Technical information

The video scrambling method involved horizontally displacing alternating slats of the image, creating an effect similar to venetian blinds; decoding reversed this displacement to restore picture alignment. Additionally, video signals underwent phase inversion that swapped black and white elements. Audio scrambling employed frequency inversion by shifting sound frequencies upward by 2.625 kHz, resulting in audio resembling single sideband radio with predominantly high-frequency components.

Audio descrambling utilized a dual-conversion technique: initially shifting frequencies up by 31.5 kHz before shifting down by 34.125 kHz, yielding an effective downward shift of 2.625 kHz. These frequency values were synchronized with the horizontal sweep frequency (15.750 kHz) to ensure precise tuning. The system’s stringent frequency tolerance allowed detection of errors if broadcasts were recorded and replayed later. Frequency shifts also became noticeable during local commercial breaks.

A major drawback was Phonevision’s incompatibility with color transmissions due to interference with the 3.58 MHz phase lock essential for NTSC color signals. This limitation, combined with the FCC’s approval of subscription programming in 1969, contributed significantly to Phonevision’s eventual discontinuation.