such as cards, paper money and dice to enhance the games. It had features that became industry standard in subsequent generations such as detachable controllers, light gun accessories and interchangeable game cartridges. While no game data was stored on the cartridges as they would be in future consoles, they could be used to select one of the twelve games built onto the hardware. Magnavox licensed its video game patents to other companies for a fee and prosecuted companies who released consoles without a licensing agreement. It was with the Odyssey that Nintendo first became involved in the home video game market. According to Martin Picard in the International Journal of Computer Game Research: "in 1971, Nintendo had – even before the marketing of the first home console in the United States – an alliance with the American pioneer Magnavox to develop and produce optoelectronic guns for the Odyssey, since it was similar to what Nintendo was able to offer in the Japanese toy market in [the] 1970s." In 1974 Philips purchased Magnavox and released a series of eight Odyssey consoles in North America from 1975 to 1977. All of them were dedicated consoles, and each subsequent release was an improvement over the previous, adding features such as additional game variations, on-screen displays, and player-controlled handicaps such as smaller paddle sizes and variable ball speed. Three Odyssey series consoles were also released in Europe with similar features from 1976 to 1978. TV Tennis Electrotennis On September 12, 1975, several months before the release of Home Pong in North America, Epoch released Japan's first home console, the TV Tennis Electrotennis. The technology was licensed from Magnavox and it contained a single ball and paddle style game that resembled Pong but without an onscreen score display. The game controls were contained within the base unit and it connected to a television set through an ultra high frequency (UHF) antenna, as opposed to being directly connected, which was unique to the console at the time. Compared to popular consoles of the generation, it performed poorly with an approximate 20,000 units sold. Atari Home Pong In late 1975 Atari released a home version of their popular arcade game Pong. It was the first use of a microchip in an Atari product and had been in development since 1974 under the lead of Allan Alcorn and Harold Lee. By the end of 1975, Atari had become