RADAR Data Blocks

Every commercial flight is equipped with a transponder. This electronic device is connected to the on-board computer. It transmits coded radio signals to the controller's radar receiver. These signals contain information about the flight: aircraft's identification letters or flight number and its altitude. Upon departure, pilots receive a 4-digit transponder code and set their transponder to that code. The terminology is "Squawk" 1200. The standard transponder code for VFR flights is 1200. When the code is set, the radar "blip" for that flight shows as an enhanced signal on the controller's radar screen. The aircraft is shown in motion on the screen and is followed by a box with the flight's information in itthe data block. This way controllers can visually track each flight as it flies through their designated airspace.