NEXUS STAR Concept

Redundancy

The newly designed RBPR NEXUS STAR backplane supports a redundant configuration with central controller boards and the RCX routing matrix. If there are two RCX boards installed on the NEXUS STAR, the Base Device can switch over to the spare board in case of malfunction. All routing and other settings will be applied to the spare board.
The RBPR, too, supports redundancy by design. Just like normal NEXUS Base Devices, the NEXUS STAR can be configured with (up to four) redundant power-supply units fed from separate mains. At failure, the router switches over to a spare signal path automatically and without signal interruption.
With this new hardware architecture, the NEXUS STAR offers a remarkable level of security: Even a defective board damaging the bus system would not result in router failure.
Extra security is provided by establishing redundant cable connections between the NEXUS Base Devices and the NEXUS STAR. The NEXUS transmits every signal from the Base Device over the two parallel lines to the NEXUS STAR. The router decides which of the two input signals should be used. Both signals are constantly monitored for data errors using CRC. The NEXUS will normally ignore the redundant signal; however, if an error occurs on the active signal while the secondary signal received in parallel is still »good«, the NEXUS will automatically switch to the other port within a single sample. The result is an smooth inaudible change to the good signal. This is true redundancy! Of course, the same is also true for the return path to the Base Device.