US Patent 7823702 Elevator monitoring system including automatic passenger detection

In an elevator monitoring system, an operation monitoring apparatus receives operation condition data from a group supervisory control device so as to display operation conditions of elevators on a monitor. The operation monitoring apparatus and the interphone base device can telephone-communicate with each other. The operation monitoring apparatus detects that a passenger within a car of at least one of the elevators cannot perform an interphone communication based upon the operation condition data and information of communication conditions with respect to the interphone terminal devices, which are received from the interphone base device.