In Star Trek: The Original Series, Captain Kirk uses a communicator to communicate with starships.
The communicator is a portable, two-way communications device used by Starfleet officers. It can contact a starship or another communicator over planetary distances and often helps the crew coordinate away missions. Its flip-open design became one of the most recognizable pieces of Star Trek technology.
The original-series communicator was influential beyond television. Martin Cooper, who led development of the first handheld mobile phone at Motorola, identified the Star Trek communicator as an inspiration. The fictional device anticipated the idea of a personal wireless handset, although real mobile phones use terrestrial networks rather than orbiting starships.
A communicator is not the same as a tricorder, which gathers scientific and medical readings, or a universal translator, which helps convert languages. Later Star Trek series used smaller comm badges and more advanced communications systems, but the classic handheld communicator remains the best-known example.