A busy signal is a signal that is heard when a telephone line is occupied. Some synonyms for the term "busy signal" include engaged tone, occupied signal, line busy signal, call waiting tone, and call waiting beep. Engaged tone is commonly used in the UK to refer to a busy signal. Occupied signal, as the name suggests, is a signal indicating that the line is currently occupied. Line busy signal is self-explanatory, whereas call waiting tone and call waiting beep indicate that the line is busy but there are other calls waiting. These synonyms can be effectively used in various communication channels to convey the same meaning as the term "busy signal.