Abstract: A danger alarm system includes a plurality of detectors, each of which having a microprocessor, a current drain controllable by the microprocessor for data exchange with a central station, an address register, and a nonvolatile memory for containing an individual binary serial number.

Abstract: A contact element suitable for SMD printed circuit boards is made of a flexible blank of sheet metal of approximate C-shaped cross-sectional configuration, with dimensions of a DIL package for SMD integrated circuits. The contact element is provided with bent terminals which are soldered onto respective bonding pads upon the circuit board while the top surface of the contact element is provided for contacting by a resilient external countercontact.

Abstract: A fire detector includes a scattered light detector unit and an ionization detector unit which are arranged upon a common base at each side of the center axis of a compartment defined by the base and a peripheral wall extending from the base. The scattered light detector includes a light source and a receiver, with their principal axes intersecting in a point of intersection which is positioned at one side of the center axis of the compartment and thus extends eccentric to the center axis. The ionization detector unit includes a holder for a preparation to be ionized, with the holder being arranged at the other side of the center axis. Suitably, a heat detector is further provided in the center axis.

Abstract: An ionization fire detector of the type including a measuring chamber and a reference chamber having a common electrode which is connected to the gate terminal of a field-effect transistor by a profile piece of conductive caoutchouc having one end contacting the gate terminal and another end contacting the common electrode.