The Nintendo DS Digital TV Tuner is a Nintendo DS accessory exclusively released in Japan in 2007 that receives broadcasts through a service called 1seg. The top screen of the Nintendo DS broadcasts the digital TV programs while you can change the channels on the lower screen. Nintendo released a version of their Game & Watch game Fire with the device. Due to digital broadcasts being replaced by cable outside of Japan, Nintendo has no plans to release the device outside of Japan.
Before the game was released, the Digital TV Turner was originally going to run through the Game Boy Advance slot of the Nintendo DS or DS Lite, though the final product runs through the DS Card slot.