Genesis:Region Information

There are three main regions for Genesis/Mega Drive hardware; Japanese, US and Europe/PAL. All of these regions are determined by two pins on the I/O chip or main ASIC, one for language (English/Japanese) and the other for video frequency (50/60 Hz). Each pin is set by either connecting them high (5V) or low (ground). Most games released before 1993 largely ignore these settings, but many released after this period perform a check to determine which console the game is running on. If the game detects a mismatch between what it expects and the console's region settings, it will not boot and often times will display a warning message (i.e. "Developed For Use Only with NTSC Genesis Systems."). Most Sega/Mega CD systems also perform this region check in their BIOS, and it cannot be bypassed without performing a region mod on the Genesis/Mega Drive console or replacing the BIOS on the CD hardware with a region-free one.

Unlike its predecessor, the Genesis/Mega Drive uses the exact same cartridge pinout and connector across all regions.

Asian/Japanese/Korean
Japanese and Korean consoles have the language pin held low (JP) and the video frequency pin held high (60 Hz). Asian market consoles are largely the same as their Japanese counterparts but run at 50 Hz as many Asian countries use PAL. One important note about Japanese cartridges is that they have a different shape than Western cartridges, and will not fit in a Genesis or European Mega Drive without physically modifying the console shell or using an adapter.

North American/Brazilian
North American and Brazilian consoles have both the language and video frequency pins held high (EN, 60 Hz).

Europe/PAL
PAL consoles have the language pin held high (EN) and the video frequency pin held low (50 Hz).