Bilateral master station-plural satellite station signalling apparatus
First Claim
1. In combination, station means for transmitting and receiving plural bit messages comprising an address field, a data field and an encryption field;
- said station means including;
a state counter;
received message demodulating means;
station address storing register means;
error signal multiplexer means having plural data inputs, an output for selectively setting said state counter to a predetermined state, and addressing control means connected to the output of said state counter for interconnecting one of said multiplexer data inputs with said multiplexer output depending upon the content of said state counter;
address error means having inputs connected to said station address storing register means and said demodulating means and an output connected to a first one of said plural error signal multiplexer inputs; and
encryption field verifying means having an input connected to said demodulating means and an output connected to a second input of said error signal multiplexer means.
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Abstract
A bilateral digital signalling network couples a master station and plural remote, or satellite stations via a common communications link--as by way of an MATV coaxial cable. Any data/control signals may be interchanged by the system stations--for example sensor station and closure latches in an apartment complex security system multiplexing security signals on the MATV video program disseminating cable.
The system employs sequential multi-mode remote stations. In accordance with varying aspects of the present invention, encryption verification is required and performed on transmission address and data fields; satellite stations revert to a predetermined secure state if not polled frequently enough by a master station; and structure is provided to prevent a station from failing in a "talking" condition which blocks (masks) all upstream transmission.
168 Citations
19 Claims
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1. In combination, station means for transmitting and receiving plural bit messages comprising an address field, a data field and an encryption field;
- said station means including;
a state counter; received message demodulating means; station address storing register means; error signal multiplexer means having plural data inputs, an output for selectively setting said state counter to a predetermined state, and addressing control means connected to the output of said state counter for interconnecting one of said multiplexer data inputs with said multiplexer output depending upon the content of said state counter; address error means having inputs connected to said station address storing register means and said demodulating means and an output connected to a first one of said plural error signal multiplexer inputs; and encryption field verifying means having an input connected to said demodulating means and an output connected to a second input of said error signal multiplexer means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
- said station means including;
- 18. In combination, common transmission means, plural transmitting and receiving stations connected to said common transmission means, each of said stations including transmitting means for supplying a modulated carrier wave to said common transmission means, the transmission carrier wave frequencies of said stations being substantially equal, receiving and data processing means for receiving and processing information transmitted to said station on said common transmission means, first energy source means for continuously energizing said receiving and data processing means, second, discretely operative energy source means for energizing said transmitting means in an interrupted manner, and supply means connecting said first and second energy source means for refreshing energy in said second energy source means, said supply means including coupling means for refreshing said second energy source means at a rate less than the rate at which said transmitting means draws energy from said second energy source means, whereby any one of said stations is thereby prevented from failing in a constantly transmitting mode to mask all transmissions on said common transmission means.
Specification