Operational Description

A central station application, "hot" redundant alarm receivers enable the highest level of dependability from a life safety alarm monitoring system. In a hot redundant configuration, each individual system that is part of the hot redundant system serves as the automatic backup to the other system. This configuration is particularly effective in active network radio installations.

How it works
Each individual system may include any or all of the standard functionality inherent in Keltron's powerful DMP703/704 alarm monitoring and receiving systems. Functionality includes the simultaneous monitoring of direct connects, coded signals and, with the DR703Le digital system option, digital alarm radio transmitters (DARTs) and digital alarm communicator transmitters (DACTs). For example, one system can monitor up to 16 dialup telephone lines, redundant radio receivers, and up to 20,000 reverse polarity or EOL direct connect accounts.

Hot redundant systems can achieve significant cost savings by allowing a single system platform to receive all types of alarms.

In hot redundant installations, the active system performs monitoring activities as described above. The second, identical system remains on standby. The active system provides the operator interface - annunciation, printing, line failure reporting - and supplies output to automation as required. The standby system is connected to the active system via a serial interprocessor link (IPL). The IPL maintains standby system readiness for input status, database contents, etc. Synchronization by the IPL ensures that any switchover is transparent to automation and to the operator.