In telecommunication, a hotline (also called an automatic signaling service, ringdown, or off-hook service) 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. True hotlines can't be used to originate calls other than to preselected destinations. Howe… (More on Hotline)