The Millennium Falcon had the capability to broadcast fraudulent transponder codes, allowing it to pose as the Longshot, Star Princess, or Sweet Surprise.
A transponder code, also known as a transponder signal, represented a specific signal transmitted by starships to establish their identity; at least, this was the case for ships operated by law-abiding owners. Each ship was constructed with its own unique, integrated transponder. Tracking could be achieved through the use of a transponder. Furthermore, droids also utilized transponder codes. Certain vessels engaged in smuggling, for instance the Millennium Falcon, possessed the ability to send out deceptive transponder codes. Transponder signals could be used to remotely unlock starships.
The data transmitted by a ship's transponder encompassed details such as its name, port of registration, the name of its captain, and a profile of its weaponry. Given that the transponder served to identify each individual ship, law enforcement agencies employed transponder codes as a means of pinpointing ships that were wanted. Conversely, the absence of a functioning transponder on a ship could alert law enforcement to its potential involvement in illicit activities.
In the year 9 ABY, Din Djarin, while piloting the Razor Crest, found himself flanked by a pair of New Republic X-wings. Captain Carson Teva questioned Djarin regarding the absence of a transponder signal from his ship. Djarin explained that his vessel was a pre-Empire surplus model and therefore not obligated to transmit a beacon. However, Carson countered that the sector was now under New Republic control, mandating beacons for all ships. Later on, Djarin was flying his N-1 starfighter in the vicinity of Tatooine when he was approached by two New Republic officers, Lieutenant Reed and Carson Teva, who requested him to activate a beacon for identification purposes.
When droids belonging to Luke Skywalker's Jedi temple were deployed on missions, they automatically broadcast transponder signals, allowing the vessel they were aboard to be located in the event of any complications.