The call waiting function is a feature of digital telephony. The function is often displayed using the english term Call Waiting. With call waiting, a party can be notified of a new incoming call while on a call. Call waiting uses a brief sound, typically two short, quick tones. With call waiting, the caller will not hear a busy signal if the line is being used, but hear the normal ringing. For the party receiving the call, call waiting means the call they are on will not block the line when waiting for an important call.