Transponder

A transponder was a type of tracking device on board a starship, starbase, or other spacecraft, which broadcast a signal identifying that craft by name, design, and allegiance. This allowed for easy recognition of craft, especially at distances where visual inspection or accurate sensor readings were not possible.
Transponders could be deactivated or have their details forged, however, so the existence or absence of a transponder signal was not proof-positive of a craft's identity or existence. For this reason, transponder signals could include some kind of code proving to those "in-the-know" that the signal was genuine.
In August 2151, Transponder 4 of Echo 1 was used to relay a subspace communication between Admiral Maxwell Forrest at Starfleet Command on Earth and Captain Jonathan Archer aboard Enterprise. ()
In 2153, Osaarian pirates were equipped with small transponders. Usually, on raiding missions, each Osaarian had one of the devices attached to the right shoulder of his own uniform. However, the transponders could be quickly detached and applied to other items, such as cargo selected for transport. ()
In May 2154, Arik Soong had a transponder implanted to prevent him from escaping from . He later deactivated it on Verex III with a stun baton. ()
In 2259, Lieutenant jg Montgomery Scott constructed a Gorn transponder by cannibalizing a Hubble K7C Stellar Assessment Array from the . This allowed him to fool the Gorn into seeing his shuttle as one of their own. Later, he salvaged the device and brought it with him to the . ()
In 2369, Chief Miles O'Brien and Lieutenant Jadzia Dax searched for the crash landed runabout and were even unable to find the transponder signal of the runabout. ()
Later in 2371, O'Brien planted a transponder on a Flaxian ship that visited Deep Space 9 that year. It was detectable within a range of a half-light year, however, the ship was destroyed before it could be put to use. Following the destruction of the ship, O'Brien was nevertheless able to analyze the telemetry from the transponder and an interference pattern in the transponder's signal, indicating the ship was destroyed by a forced neutrino inverter. ()
While fleeing from the Changeling-compromised Starfleet in 2401, the dropped several transponders as decoys to throw off its pursuers. Admiral Jean-Luc Picard subsequently sought Commodore Geordi La Forge's help in cloning the Titans transponder signal as a more permanent means of disguising their position. However, La Forge informed him that this could only be accomplished with randomized Starfleet security codes, and that doing so would be futile anyway since all ships in the fleet had been integrated and would automatically communicate if they neared each other. ()
== See also ==
* Emergency transponder
* Homing transponder
* Subcutaneous transponder
* Subspace marker 
== External link ==
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Category:Communications technology