A telephone hook or switchhook is the cradle where a telephone

Telephone

The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...

 handset resides. It takes its name from old wooden wall telephones and candlestick telephone

Candlestick telephone

The candlestick telephone is a style of telephone that was common from the late 1890s to the 1930s.-History:Also known as a desk stand, upright, or a stick phone, it came with or without a rotary dial, and with a ringer box...

s, where the mouthpiece to be mounted on the telephone box and, due to sidetone

Sidetone

Sidetone is audible feedback to someone who is speaking. The term is most used in telecommunication contexts.-Telephony:In telephony, sidetone is the effect of sound that is picked up by the telephone's mouthpiece and in real-time introduced at a low level into the earpiece of the same handset,...

 considerations, the receiver

Transceiver

A transceiver is a device comprising both a transmitter and a receiver which are combined and share common circuitry or a single housing. When no circuitry is common between transmit and receive functions, the device is a transmitter-receiver. The term originated in the early 1920s...

 was separate, on a cable. When the telephone was not in use, the receiver was hung on a spring-loaded hook; its weight would cause the hook to swing down and open an electrical contact, disconnecting the telephone from the line. When the handset is on the cradle, the telephone is said to be "on-hook

On-hook

In telephony, the term on-hook has the following meanings:# The condition that exists when a telephone or other user instrument is not in use, i.e., when idle waiting for a call. Note: on-hook originally referred to the storage of an idle telephone receiver, i.e., separate earpiece, on a switchhook...

", or ready for a call. When the handset is off the cradle, the telephone is said to be "off-hook

Off-hook

In telephony, the term off-hook has the following meanings:# The condition that exists when a telephone or other user instrument is in use, i.e., during dialing or communicating. Note: off-hook originally referred to the condition that prevailed when telephones had a separate earpiece , which hung...

", or unable to receive any (further) calls.

Example usage

"I tried calling you all day, but your phone must have been off the hook, because all I got was a busy signal."

Additional usage

A phone receiving many calls in rapid succession can be said to be "ringing off the hook". (Often cartoons will show a telephone handset literally bouncing above the ringing base unit.) This most likely led to the present use of "off the hook" as a synonym for "crazy" or "exciting". "Last night was off the hook" may mean "last night was really awesome"

"Off the hook", meaning "freed from responsibility or culpability" is not related to the telephone, but most likely derives from the image of a worm or fish dislodging itself from a fish hook

Fish hook

A fish hook is a device for catching fish either by impaling them in the mouth or, more rarely, by snagging the body of the fish. Fish hooks have been employed for centuries by fishermen to catch fresh and saltwater fish. In 2005, the fish hook was chosen by Forbes as one of the top twenty tools...

.

See also

• Hook flash
  Hook Flash
  Hook flash or flash is a button on a telephone that simulates quickly hanging up then picking up again . This action can signal the telephone exchange to do something. A common use of hook flash is to switch to another incoming call with the call waiting service...
  
  
• Off the Hook: radio show
• Permanent signal
  Permanent signal
  Permanent Signal in US telephony jargon, or Permanent Loop in British usage, is a condition in which a POTS line is off-hook without connection for an extended period of time. This is indicated in modern switches by the silent termination after the off hook tone times out and the telephone...