The Codec is the radio system used throughout the Metal Gear Solid series, introduced in the 1998 PlayStation game, where Snake receives briefings through an earpiece interface. Its menu and call-ending tones became part of the series identity alongside alerts and the enemy spotted style callouts familiar to tactical game players. Clips of the exit tone spread through gaming forums, YouTube edits and soundboards as a compact sign-off sound. It remains popular because a single short beep instantly signals mission over, conversation closed, and scene ended.