초록 ▼

A multiplex security system provides two-way data communications between a local panel and multiple microprocessor-based remote panels interconnected over a common data transmission line. A second line provides two-way voice communications between the local and remote panels with automatic forwardin

A multiplex security system provides two-way data communications between a local panel and multiple microprocessor-based remote panels interconnected over a common data transmission line. A second line provides two-way voice communications between the local and remote panels with automatic forwarding by an audio/data control selector to a central control unit via a single telephone line. Two additional lines provide a common ground and transmit DC power from the local to the remote panels. The remote panels include bus drivers connected to the communications line for transmitting both ASCII digital data messages and a higher voltage request or SRQ signal to the local panel when the remote panel has a message to transmit. The local panel includes two separate receivers for distinguishing the request signal from digital data and a bus driver for transmitting data. The local panel transmits a grant message which is superimposed over the request signal, reducing its voltage level to zero. The remote panel has a receiver for receiving ASCII data from the local panel and for sensing the reduced voltage level to turn off the request signal. The remote panels are assigned priorities by setting different switch numbers in each panel. The switch numbers correspond to unique brief time slots in which each of the remote panels can commence transmitting. Following a grant command, the remote panels count time slots. None can respond until the count equals its respective switch number, and then only if another panel has not already commenced transmitting.

대표청구항 ▼

A security communications system comprising: a local panel and a plurality of remote panels interconnected by a common bi-directional data line and a common bi-directional voice line; remote speaker means and microphone means in each of the remote panels for receiving and transmitting audio signals

A security communications system comprising: a local panel and a plurality of remote panels interconnected by a common bi-directional data line and a common bi-directional voice line; remote speaker means and microphone means in each of the remote panels for receiving and transmitting audio signals via said voice line; local speaker means in the local panel for receiving and reproducing sounds transmitted over said voice line; and logic means in each of the remote and local panels connected to transmit and receive data signals via the data line, including a unique data signal from the remote panel to request enabling of the local speaker means; the remote panel logic means being controllingly connected to the remote speaker means and microphone means; the local panel logic means being controllingly connected to the local speaker means and responsive to receiving said unique data signal via the data line from the logic means of one of the remote panels for selectably enabling said local speaker means to output an audio signal transmitted over the voice line from the microphone means of said one of the remote panels.