The Cone of Silence is one of many recurring joke devices from Get Smart, a 1960s American comedy television series about an inept spy. The essence of the joke is that the apparatus, designed for secret conversations, makes it impossible for those inside the device – and easy for those outside the device – to hear the conversation.
The larger, plastic version of the "Cone of Silence" appeared in "Mr. Big", the pilot episode of Get Smart, which aired on September 18, 1965. Mel Brooks and Buck Henry, the original screenwriters for the series, devised many of the running jokes. The Cone of Silence scene was shot ahead of the rest of the pilot episode, and was used to sell the series to NBC.[1]