The combadge has become the ubiquitous symbol of Starfleet in the 24th century. More than just the insignia of the organization, it has evolved to the point where it is now the technological tether for an officer to his ship.
Circuitry miniaturization allowed for the standalone technology of the communicator to be implemented into the badge that has been standard on Starfleet uniforms since its inception. Worn on the left breast of the uniform, its primary function is to provide communication, be it onboard, ship-to-shore, or directly with another combadge. Due to its size, the combadge has limited transmission range, but the signal can be boosted by a starship’s communications systems. As part of its communications abilities, it also contains a fully-fledged universal translator circuit.