From Bulbapedia, the community-driven Pokémon encyclopedia.
The In-Com is a headset device that allows Shū to talk to his Pikachu. It is only seen in the manga Pokémon Get da ze!.
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.
The character Masatoshi is able to communicate with his Meowth through a hood with two Meowth ears.