communicator
Star Trek: The Original Series
Episode: TOS 001 - Cage, The
A portable transceiver device in use by Starfleet crews since the mid-22nd century.
Earlier versions were designed as a hand-held device with a hardware control interface and a flip-up antennae grid/activator, but by the 2340s the communicator functions had been built into the metallic uniform insignia "combadge" worn on the left breast, activated by touch or voice.
Among many uses, communicators serve as locator IDs for gaining a transporter lock on personnel.
