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The Sup 'R' Mod II was an RF modulator sold by M&R Enterprises in the late 1970s and early 1980s. It allowed the connection of computers and other devices with composite video outputs to a television.[1]


Apple Inc. wanted to provide users of their Apple II computers with a way to view color output on a television, but they had trouble getting FCC approval, because the RF modulation solution they were using was too noisy. Apple made an arrangement with a small nearby company, called M&R Enterprises, to manufacture and sell the devices. While Apple could not sell the modulator and computer as a package, retail computer dealers could sell both devices to the end user.[2]

Marty Spergel, who ran M&R Enterprises, was told by Steve Jobs that it might sell as many as 50 units a month. Spergel later estimated that he had sold about 400,000 units.[3]

The Sup 'R' Mod II began selling in April 1978, for $29.95.[4]

Technical features[edit]

Modulator and antenna switch.

The Sup 'R' Mod II kit came with a small printed circuit board, an antenna switch, and a coaxial cable with a ferrite core and RCA connectors. Composite video was received by the circuit board through a short cable terminating in a molex connector, which plugged into a header on the Apple II motherboard. Input could also be provided through an RCA connector. The output of the RF modulator went out through a coaxial cable to the antenna switch.[5][6]

The antenna switch allowed the user to select between television broadcasts and computer output. The television antenna was connected to inputs on the switch, and the switch output was connected to the back of the television. The connections used screw terminals with spade lugs. Moving the switch from "TV" to "GAME PLAY" selected the computer output.

The board and antenna switch came with a bit of double-sided tape to allow the user to attach them to the inside of the computer case and the side of the television, respectively.

The modulator presented a color signal on UHF channel 33.[4]


  1. ^ "Apple II History - Sup'R'Mod".
  2. ^ "3-The Apple II". Apple II History.
  3. ^ Levy, Steven (1984). Hackers: Heroes of the Computer Revolution. New York: Dell Publishing Co. pp. 260–261.
  4. ^ a b "Apple Contact, issue #1" (PDF).
  5. ^ "Sup'R'Mod II Manual, page 1".
  6. ^ "Sup'R'Mod II Manual, page 2".