2 results about "Off-hook" patented technology

In telephony, on-hook and off-hook refer to the two possible states of a receiver. Off-hook originally referred to the condition that prevailed when telephones had a separate earpiece (i.e., receiver), which hung from its switchhook until the user wished to activate it. When off hook the weight of the receiver no longer depresses the spring-loaded switchhook, thereby connecting the instrument to the telephone line.