A method for dynamically partitioning a security system is described. A security system identifies sensors registered with the security system. The security system then identifies a first partition attribute of a first group of sensors of the sensors. The first partition attribute indicates a primary partition of the security system. The security system then identifies a second partition attribute of a second group of sensors of the sensors. The second partition attribute indicates a secondary partition of the security system. The security system forms a dynamic partition of the security system based on a combination of the first and second partition attributes.

Systems and methods for interfacing a hazard detection device with a control panel system via a dongle are provided. The dongle may be configured to alternate between drawing first and second amounts of power from the control panel system in response to the hazard detection device alternating between operating in a normal mode when no hazard is detected and an alarm mode when a hazard is detected. The hazard detection device may operate independently of any characteristics of the control panel system. For example, the hazard detection device may operate without drawing any power from the control panel system. Therefore, the dongle may allow for various types of hazard detection devices to interface with a common two-line power control system.

An audio riser active electrical supervision system includes a high-voltage audio alert system connected to a riser circuit. The high-voltage audio alert system disconnects a high-voltage analog signal from the riser circuit when the audio riser active electrical supervision system operates in a standby mode, and connects the high-voltage analog signal to the riser circuit when the audio riser active electrical supervision system operates in an active alert mode. A plurality of isolator modules operate in a closed state that connects a circuit node to the riser circuit and an open state that disconnects the respective circuit node from the riser circuit. A riser supervision circuit is connected to at least one isolator module to detect a circuit fault on the riser circuit when the audio riser active electrical supervision system operates in the standby mode and the active alert mode.

An audio riser active electrical supervision system includes a high-voltage audio alert system connected to a riser circuit. The high-voltage audio alert system disconnects a high-voltage analog signal from the riser circuit when the audio riser active electrical supervision system operates in a standby mode, and connects the high-voltage analog signal to the riser circuit when the audio riser active electrical supervision system operates in an active alert mode. A plurality of isolator modules operate in a closed state that connects a circuit node to the riser circuit and an open state that disconnects the respective circuit node from the riser circuit. A riser supervision circuit is connected to at least one isolator module to detect a circuit fault on the riser circuit when the audio riser active electrical supervision system operates in the standby mode and the active alert mode.

A disconnection detection device for an in-vehicle device having a load circuit, is provided with a second wire harness which is arranged along at least a part of the first wire harness, a current circuit which supplies a current for disconnection detection to the second wire harness, and a disconnection determination circuit which monitors an output voltage of the current circuit so as to determine presence or absence of disconnection of the second wire harness. Disconnection of the second wire harness is detected as the disconnection of the first wire harness based on disconnection determination of the disconnection determination circuit.

A disconnection detection device for an in-vehicle device having a load circuit, is provided with a second wire harness which is arranged along at least a part of the first wire harness, a current circuit which supplies a current for disconnection detection to the second wire harness, and a disconnection determination circuit which monitors an output voltage of the current circuit so as to determine presence or absence of disconnection of the second wire harness. Disconnection of the second wire harness is detected as the disconnection of the first wire harness based on disconnection determination of the disconnection determination circuit.

A disconnection detection device is provided with a disconnection detection unit including a constant current circuit configured to supply a constant current for disconnection detection to at least two horns through wire harnesses, and a disconnection detection circuit configured to determine the presence or absence of disconnection of the wire harnesses by monitoring an output voltage of the constant current circuit and configured to supply drive power through the wire harnesses by turning on the contact circuit independently of the horn switch in a case where disconnection of the wire harnesses has been detected. The disconnection detection unit is disposed in the relay box along with the plug-in relay.

A disconnection detection device is provided with a disconnection detection unit including a constant current circuit configured to supply a constant current for disconnection detection to at least two horns through wire harnesses, and a disconnection detection circuit configured to determine the presence or absence of disconnection of the wire harnesses by monitoring an output voltage of the constant current circuit and configured to supply drive power through the wire harnesses by turning on the contact circuit independently of the horn switch in a case where disconnection of the wire harnesses has been detected. The disconnection detection unit is disposed in the relay box along with the plug-in relay.

A method of locating a short circuit in a system including a set of components electrically connected in a loop, such as a fire protection system. It is iteratively determined in which location of a set of possible locations a short circuit is located. Each iteration involves determining in which of two subsets of a set of remaining locations the short circuit is located, and eliminating from the set of remaining locations the subset in which the short circuit is determined not to be located.

The invention relates to a bus system (1) comprising a control unit (2) and at least one bus node (3.1, 3.2, 3.3). The control unit (2) is allocated at least two data communication interfaces (2.1, 2.2) which are respectively designed to transmit and receive data. The at least one bus node (3.1, 3.2, 3.3) comprises a bus coupler having at least two data communication interfaces (3.11, 3.12; 3.21, 3.22; 3.31, 3.32) respectively designed to transmit and receive data. The control unit (2) and the at least one bus node (3.1, 3.2, 3.3) are respectively connected together via their data communication interfaces and corresponding two-point connections (8) to form a ring topology. The bus coupler of the at least one bus node is designed to directly and without delay transmit, and thus forward, data received at one of its at least two communication interfaces via its other data communication interface.