Master Gear Converter
From Sega Retro
The Master Gear Converter, sometimes known simply as the Master Gear, Gear Master Converter or in Brazil, Master Gear Adaptor is an accessory for the Sega Game Gear, allowing the unit to play Sega Master System games.
The history of the device is not fully understood. It was developed by the Hong Kong company, Kalplus and originally released in late 1991. However, there are many different varieties of this device, some officially branded by Sega, so the distribution chain remains a mystery. Kalplus filed a US patent for the device in late 1991, which they held for a brief period between 1993 and 1994, and they also held the "Master Gear" trademark for a while.
The Master System Converter is a simplistic device which fits into the Game Gear's cartridge slot, which in turn allows for western-style Master System cartridges to be placed inside and run on the Game Gear, similar in nature to the Power Base Converter for the Sega Mega Drive. The Game Gear is essentially an upgraded Master System and thus has no trouble playing Master System games, however is unable to offer any other advantages such as FM Sound offered by the FM Sound Unit. It also cannot run Sega Cards natively, though could in theory do when armed with a Card Catcher and a Master System Region Converter.
When playing Master System games, the output is resized to fit the Game Gear's smaller screen. This can make some games more difficult to play, as smaller sprites become difficult to make out such as bullets or text. The Master Link Cable can be used to use a controller to play two player mode in compatible games. Games which rely on the Light Phaser or 3D Glasses will also struggle. All Game Gears are region free, so the converters are likewise region free.
Some games are not fully compatible with the Master System Converter for various reasons, such as Lord of the Sword, Phantasy Star and Outrun. The unit will also not function in a late 90s Majesco Game Gear, however the updated version of the unit, the Master System Converter 2, will. The Master System Converter 2 is otherwise identical to the original model - plans were once put in place to allow a second control pad to be inserted, but no such feature can be found in the final release.