Multisensor fire detector with integrated optical sensor and heat sensor which give both a combined signal as well as a separate heat signal for improved false alarm management, with time-controlled signal analysis and weighted data combination of both detector functions for detecting smoldering fires and fires with extreme heat generation. Intelligent detector with decentralized intelligence, self-function test, CPU redundancy mode, automatic adaptation to the environments, alarm and operating data storage, alarm indication and soft addressing. The loop isolator is integrated in the detector. A remote indicator is additionally attachable.