Hardware
Labeled as a "game enhancer" device by Datel, the Action Replay DS plugs into the Nintendo DS cartridge slot (not the Game Boy Advanced slot) on any Nintendo DS or DS Lite system. Nintendo DS games are then inserted directly into the Action Replay DS. The device then monitors and overwrites specific registries in the game's memory to activate cheat codes.
Software Interface
When turning on the Nintendo DS while the Action Replay is connected, you won't go to the usual start menu--the Action Replay interface will be displayed. The top screen will show the version of your Action Replay along with the name of the DS game you have inserted into the Action Replay, and the bottom touch screen will display a large start button along with three smaller buttons: an asterisk, a wrench and a mouse.
Activating Cheat Codes
Choosing the asterisk from the choices will bring up the cheat code menu on the top screen. Using the directional pad, you can scroll through and select all available codes for your current game. Once your codes are selected, hit the start button on the touch screen and the game will start normally.
Finding Cheat Codes
Codejunkies.com is the consumer website for Datel and the Action Replay. The website allows you to download cheat codes and game saves free of charge. Datel also sells its entire selection of products, including all versions of their Action Replay, from Codejunkies.com.
Problems
In 2009, the Action Replay DS only functions with the original Nintendo DS and DS Lite, but not with the DSi. Also, the software used to connect the Action Replay to the Internet, in order to download new cheat codes and update software, would only function correctly on Windows XP.
Additionally, because the device directly writes on the memory of the game cartridge, it is possible that poorly written cheat codes can corrupt data and permanently damage saved game files.