Transtator

A transtator was a piece of technology which formed a basic part of numerous devices, including communicators, transporters, and phasers. The transtator was a necessary component for detecting and manipulating subspace energy. 

Captain James T. Kirk was concerned, after Leonard McCoy left his communicator on Sigma Iotia II, that the Iotians might learn how the transtator worked, and replicate this technology. 

Miles O'Brien accidentally caused a power outage on the USS Enterprise (NCC-1701) in 2268 by disconnecting a shipboard transtator. 

A 23rd century ion-transtator was among the items discovered in an Andorian chest aboard a derelict freighter in 2373, and later auctioned off at Quark's. 

Transtators continued to be used into the 24th century, aboard the of starships.