Lift alarm system using telephone network - provides initial alarm at surveillance point and only alerts emergency service after given time interval

摘要

The alarm system has an alarm button within the lift cabin which can be operated upon light failure. The alarm button is coupled via a first alarm circuit to a surveillance point at which an alarm signal is provided upon actuation of the button. A second alarm circuit couples it to an assistance point at which an alarm signal is given only if the alarm button remains activated after a given time period, eg. if the surveillance point is unmanned. Pref. the second alarm circuit uses the telephone network to put an automatic call through to the relevant emergency serVice. This removes the need to instal a telephone within the lift cabin, which presents connection problems and is prone to vandalism.