A 24th Century 52-L transtator
A 23rd Century ion-transtator.
The transtator is one of the key elements of Federation technology, forming part of a wide variety of systems and devices.
23rd century communicators incorporated a transtator. When Leonard McCoy left his behind on Sigma Iotia II, James Kirk was concerned that the native Iotians, already culturally contaminated, might discover how the transtator worked, and thus emulate the technology of the Federation. (TOS: "A Piece of the Action")
Transtators also formed part of a starship's power system. Miles O'Brien accidentally disconnected a transtator from the power grid of the USS Enterprise whilst infiltrating that vessel in 2267, causing a localised power blackout. (DS9: "Trials and Tribble-ations")
Despite advances in computer technology, such as isolinear chips and bio-neural gel packs, the transtator continued to be used into the 24th century. The USS Voyager carried transtator assemblies aboard, diagnostics of which were routinely performed by operations manager Harry Kim. (VOY: "Time and Again")
A 23rd century ion-transtator was among the items discovered in an Andorian chest aboard a derelict freighter in 2373. The chest and its contents were later auctioned at Quark's Bar. (DS9: "In the Cards")