What Is a Phone Hook Switch?

By Julia Selch

The hook switch on your telephone is automatically activated when you pick up.
i telephone 1 image by Aussiebloke from Fotolia.com

Old fashioned telephones had a physical hook switch which was pressed down while the receiver was resting on the cradle base. This small button is no longer visible on modern phones, but maintains an important purpose.


The telephone was invented by several great inventors and patented in 1876 by Alexander Graham Bell. This gave birth to Bell Telephone, which enabled local exchanges within major U.S. cities.

The Old Hook Switch

The old phone hook switch was the physical button depressed when the telephone receiver was laid on top of the cradle base. This closed the active line of communication and meant the phone was "on hook." When the receiver was in turn picked up from the cradle and taken "off hook," a new dial tone could be heard and a line of communication was opened.

The Modern Phone Hook Switch

Today a physical phone hook switch no longer exists. Instead, a new line is automatically opened when you pick up the phone and closed when you press the "End" button to hang up.