A Transponder (トランスポンダ, Toransuponda) is a device that transmits a ship's name, registration, present position and heading. All ships in space are required to have a transponder active at all times .
A transponder is a device which is installed on a spacecraft which sends out a signal with information on the ship's name, it's registration details, present position and heading, identifying the ship to other ships and systems in the vicinity. This is done in order to identify which ships are present in a region of space at one time, allowing for those ships to keep track of one another and adjust their actions accordingly, as well as for control stations to coordinate traffic .
By law, all ships in space are required to have a transponder active at all times. However some ships might fly at times with their transponder off in situations where they don't want to be identified, though other ships will likely interpret it as a sign that they are hostile and take action . There are also cases when transponders are used to fake a ship's ID signal in order to deceive other vessels .