As seen in at least two instances, the Original Series episodes "Tomorrow Is Yesterday" and "Day of the Dove," it can also serve as an emergency signaling device/beacon, similar to a transponder.

In Star Trek: The Original Series (TOS), communicators functioned as a plot device, stranding characters in challenging situations when they malfunctioned, were lost or stolen, or went out of range.

Wrist-worn communicators were used in Star Trek: The Motion Picture and remained in use by some Starfleet installations and vessels during the time of The Wrath of Khan.

The reason for the switch was not explained, but the non-canon source Mister Scott's Guide to the Enterprise offered the explanation that Starfleet discontinued use of the wrist-worn communicators when they were determined to be prone to repeated failures after suffering minor impacts.

In Star Trek: The Next Generation (TNG) and later series, Starfleet officers and enlisted personnel wear small communicator badges on their left breast.

According to Data in the episode "Time's Arrow, Part One" at a poker game in 1893, the badge is made out of a crystalline composite of silicon, beryllium, carbon 70 and gold.

In the Star Trek: Strange New Worlds episode "Those Old Scientists", First Officer Una Chin-Riley shows the time-traveling Ensign Boimler's communicator delta to Captain Christopher Pike.

[3] In June 2016,[4] The Wand Company Ltd. released a highly accurate and working replica of the Star Trek: The Original Series Communicator using Bluetooth to enable it to pair with, and connect to, a Bluetooth enabled mobile phone so as to allow it to be used in exactly the way envisioned in the original Star Trek TV show; to make and receive calls.

For example, locator/transponder functionality is implemented via GPS, LoJack, RFID, and radio direction finder devices, and cloud-based digital assistants perform in a way similar to the artificial intelligence of a Starfleet ship's computer.