METHOD FOR KEEPING AN OBJECT UNDER SURVEILLANCE BY MEANS OF A DIGITAL DATA NETWORK WITH A PLURALITY OF RING-OUT POINTS

摘要

The invention relates to a method for keeping an object under surveillance with a decentralized alarm detection unit and a ring-out point, interconnected by means of a digital data network with a signalling channel and a message/data channel. The method comprises the following steps: when an alarm is detected (1), information representing a desired connection is transmitted (4). The information is memorized (7) by the ring-out point, after which indication of the alarm is produced (9). Finally, if the message/data channel of the digital data network is free, a connection is established (13). At least one other ring-out point and a plurality of decentralized detection units are connected to the digital network. Upon detection of an alarm by any one of the decentralized detection units, the afore-mentioned steps are carried out between the detection unit in question and one of the ring-out points. On detection of a state of overload with incoming alarm calls, at least one of the ring-out points transmits call transfer information to a remote station of the digital data network, which transmits further alarm calls to another ring-out point.