Abstract: A digital intercom system provides DC power and multi-channel bidirectional digital communications over existing cabling such as microphone cabling used in analog intercom networks. Three or more conductors in the cabling are used for both transmitting and receiving digital signals and carrying DC power. The digital intercom system includes digital user stations and a digital master station which can be used to retrofit an existing analog intercom network or deployed in a new network. User stations can be connected to the cabling via drop cables which do not use active electronic components. The master station routes digital audio and control data packets in three or more channels based on respective network addresses of the user stations to provide point-to-point, point-to-multi-point, and party line communications among the user stations. Sessions and groups can be configured which define talker and listener user stations.

Abstract: This disclosure relates to a portable audio test tool configured for testing an audio circuit. The portable audio test tool may replace an assortment of non-portable and/or bulky test equipment. The portable audio test tool may comprise a small and efficient troubleshooting tool that includes the functionality of multiple pieces of test equipment in a hand-held, pocket sized form. The portable audio test tool may be powered by a rechargeable power source recharged via power from a wet intercom's DC voltage power circuit cable. In some implementations, the portable audio test tool may comprise a tool connector, a tone generator, a transducer, a voltage indicator device, a power circuit, a switching device, a housing, a user interface, and/or other components.

Abstract: A digital intercom system provides DC power and multi-channel bidirectional digital communications over existing cabling such as microphone cabling used in analog intercom networks. Three or more conductors in the cabling are used for both transmitting and receiving digital signals and carrying DC power. The digital intercom system includes digital user stations and a digital master station which can be used to retrofit an existing analog intercom network or deployed in a new network. User stations can be connected to the cabling via drop cables which do not use active electronic components. The master station routes digital audio and control data packets in three or more channels based on respective network addresses of the user stations to provide point-to-point, point-to-multi-point, and party line communications among the user stations. Sessions and groups can be configured which define talker and listener user stations.