Signaling device
A signaling device or signal device was a form of communications technology that transmitted a prearranged signal. Such a device was among the equipment the Vedala provided for the fourth expedition to the "mad planet" to be used to recall the group once their mission was completed.
Following the capture of Tchar and the Soul of Alar, Captain Kirk called to the group to call for retrieval, Lara pushed a button on the device and they were returned to the Vedala asteroid. (TAS: "The Jihad")
Upon completion, Kukulkan's city would have been a signaling device to contact Kukulkan. (TAS: "How Sharper Than a Serpent's Tooth")
In 2338, a landing party from the USS Tripoli speculated that a signal device sensed their presence and activated the Soong-type android Data on the Omicron Theta colony. (TNG: "Datalore")