Telepathy Tile

Telepathy Tiles are the means by which Sahasrahla, and occasionally Princess Zelda, keep in touch with Link throughout his quest in A Link to the Past. When Link approaches one of these tiles, he is able to communicate telepathically with his distant allies, at which point they will express a hint about the current dungeon to him. Neither Sahasrahla nor Zelda seem to require a Telepathy Tile of their own to communicate with Link; their innate magical power seems to make it possible without the need for such objects. Zelda is even able to contact Link through telepathy after being captured and sealed in a Crystal, while both her and Sahasrahla are sometimes able to communicate with Link without the need for him touching a tile at all, although this is presumably more difficult for them.

Trivia

 * A Telepathy Tile can be found in Chris Houlihan's Top Secret Room that allows Link to hear a message from the contest winner.