hotline

thumb|right|A typical non-dial red phone used for hotlines. This one is a prop which is on display in the Jimmy Carter Library and Museum, erroneously representing the Moscow–Washington hotline.

A hotline is a point-to-point communications link in which a call is automatically directed to the preselected destination without any additional action by the user when the end instrument goes off-hook. An example would be a phone that automatically connects to emergency services on picking up the receiver. Therefore, dedicated hotline phones do not need a rotary dial or keypad. A hotline can also be called an automatic signaling, ringdown, or off-hook service.