From Bulbapedia, the community-driven Pokémon encyclopedia.
Masatoshi wearing his hood-like translation device
The In-Com is a headset device that allows Shū to talk to his Pikachu. It is only seen in the manga Pokémon Gotta Catch 'Em All.
In the manga, the main character Shū is the only character to own a In-Com. It was invented by his father and he himself does not know how well it works.
Similarly, the character Masatoshi is able to communicate with his Meowth through a "Cat Cap", a hood with two Meowth ears.