Abstract: A power supply unit for a fire detector, especially a smoke alarm, includes a power unit and battery terminals for connecting a predeterminable battery. The power unit has first connection means for connection to a power supply network and second connection means for connecting the fire detector. In order to increase the functionality of a fire alarm, the battery terminals are operatively connected by at least one first electric connection with the second connection means. The first electric connection includes hereby at least one diode.

Abstract: A power supply unit for a fire detector, especially a smoke alarm, includes a power unit and battery terminals for connecting a predeterminable battery. The power unit has first connection means for connection to a power supply network and second connection means for connecting the fire detector. In order to increase the functionality of a fire alarm, the battery terminals are operatively connected by at least one first electric connection with the second connection means. The first electric connection includes hereby at least one diode.

Abstract: The invention relates to a filter arrangement for separating analog or digital baseband signals, for example, POTS or ISDN signals and digital wideband signals, which are simultaneously transmitted on a two-wire line of a message transmission system. In accordance with an exemplary embodiment of the invention, the filter arrangement has a bi-directional low-pass filter (4) and a bi-directional high-pass filter (3). The low-pass filter (4) includes a first filter (6) with a first passband. The first filter (6) permits flow-through of direct current. A second filter (7) with a second passband is preferably arranged assembled by connecting the inputs and outputs of the first and second filters (6, 7) in parallel.