In telephony, the term off-hook has the following meanings: The condition that exists when a telephone or other user instrument's in use, for example, during dialing or communicating. Note: off-hook originally referred to the condition that prevailed when telephones had a separate earpiece (for example, receiver), which hung from its switchhook until the user wished to activate it. The weight of the receiver no longer depresses the spring loaded switchhook, thereby connecting the instrument to… (More on Off-hook)