Interface for a supervised multi-input audible warning system

A supervised multi-input audible warning system for generating an audible alarm from at least one of multiple input circuits, comprising:

• addressable decoding means for decoding an input and generating an electrical signal of at least one frequency corresponding to the input;
• audible alarming means for transforming the electrical signal into an audible output corresponding to the frequency of the electrical signal;
• and
• an interface for selectively transmitting via a plurality of interface circuits the input to the addressable decoding means, each interface circuit including:
• means for coupling the interface circuit to a power source between a positive node and negative node of said coupling means;
• supervising means electrically connected across the coupling means between said positive and negative nodes for supervising the interface circuit for electrical faults;
• switching means, having an input through which current flows, electrically connected across the coupling means between said positive and negative nodes and an output, said output having a first output node and a second output node, for reversing current flow through the output between an alarming direction flowing from said first output node and a supervising direction flowing from said second output node;
• isolation means, having an input coupled in parallel with the switching means output between said first and second output nodes and having an output for coupling with the addressable decoding means, for allowing current in the alarming direction flowing from said first output node to flow into the addressable decoding means as the input and for blocking current flow between the interface circuit and the addressable decoding means when current is flowing in the supervising direction flowing from said second output node;
• and
• resistor means connected in parallel with the switching means output for providing a supervising current flow path through the interface circuit when current is flowing in the supervising direction;
• whereby the interface circuit is supervised for electrical faults regardless of current flow direction yet is isolated from the addressable decoding means and the other interface circuits when the current is not flowing in the alarming direction.

A multi-input audible warning system for generating an audible alarm from at least one of a plurality of multiple input circuits, comprising:

• multiple input means for providing a plurality of potential input signals for generating an audible alarm;
• addressable decoding means coupled to said multiple input means for prioritizing said potential input signals from a highest priority to a lowest priority;
• audible alarming means for generating in response to the highest priority of said potential input signals an audible frequency-response output corresponding to said highest priority input signal, said audible alarming means including means for generating a plurality of audible signal frequency outputs;
• and
• selection means coupled to said addressable deocoding means for selecting said audible frequency-response output from among said plurality of audible signal frequency outputs corresponding to one of said input signals.