Transponder Signals and Prefix Codes: Difference between revisions

StarFleet vessels transmit a transponder signal that can be used to identify them. Prefix codes prevent unauthorized personnel from taking control of the ships computers. StarFleet uses a system of transponder codes to identify and locate its starships across the vast reaches of space. All Federation vessels are equipped to emit a transponder code. This is a kind of IFF signal, which stands for Identification: Friend or Foe?, a phrase that originates with the early black-box transponders installed in aircraft on Earth in the 20th century.

==Instant Recognition==

Transponder codes in the 24th century transmit basic information about a vessel. This often includes the ship's name, political allegiance, and its class. Because transponder codes are normally broadcast over subspace, they can be used to locate a ship over very long distances, and therefore overcome many of the limitations of sensor systems.  

Of course, transponder codes are not the only way to identify a vessel. Twenty-fourth century sensor systems are extremely sophisticated and, at close range, can gather enough data to identify any known vessel. If a ship enters a heavily developed area, a network of sensors on board ships, space stations, and planetary installations can be used to relay information to a tactical operations center. All this effort achieves the same result as a single subspace receiver picking up a coded transponder signal.  

==Sensor Ghosts==

However, it is not impossible to deceive sensors. One of the primary means of identifying a ship is by using its warp signature, and ships can be modified to emit fake ones. When a Maquis group led by Thomas Riker stole the USS Defiant NX-74205, they programmed at least one Maquis ship to transmit the Defiant's warp signature. As a result, the Cardassians wasted valuable resources attempting to engage an insignificant vessel, while the Defiant was free to attack another target.