Bosch interface modules 420 Series belong to a new product generation. They can be installed as input modules in flush-mounted boxes behind light switches. The interface modules permit discreet installation in any kind of building. For surface-mount installations the modules also come in a surface-mount box.

The 420 Series interface modules are compatible with all LSN fire alarm systems and panels, with backward compatibility also ensured by the option of setting them to "Classic" mode. A rotary or DIP switch can also be used to select automatic or manual addressing, with or without auto detection.

Four new interface modules are available to choose from: The 420 Conventional Series connects conventional detectors to LSN fire panels via a four-wire network with external power supply. The input module 420 monitors up to two independent inputs with or without end-of-line resistance additionally it monitors the output voltage of a connected device. The output module 420 controls two independent open collector outputs for the connection of external devices, each of which supports a load of 700mA. The relay module 420 has a potential-free change-over contact for currents up to 1 A, which applies only a negligible load to the LSN loop.