Multiplexed alarm transmission system having alarm storage circuits

Claim 2

In a security system including a transmission line for carrying alarm information from a plurality of protected areas within a predetermined zone to a central monitor that is remote from the protected areas, zone monitoring means including alarm storage means having a separate flip flop for each protected area for storing a first data bit whenever the corresponding protected area is secure and a second data bit to indicate an alarm condition for the corresponding protected area, readout means enabled in response to the storage of said second data bit in one of said flip flops to effect the sequential readout of said alarm storage means to provide an alarm output code including a sequence of data bits coded to represent the conditions of the protected areas, nd means for enabling said alarm code to be transmitted over said transmission line to said central monitor, and line monitoring means at said central monitor including first means responsive to at least one of the data bits of said alarm code to indicate that an alarm condition has been indicated for one or more of said protected areas and second means responsive to other data bits of said alarm code sequence to determine the protected area providing an alarm.

Claim 3

In a security system including a transmission line for carrying alarm information from a plurality of protected areas to a central monitor that is remote from the protected areas, alarm source means including an individual alarm sensor for each protected area, each of said alarm sensors being operable to provide an alarm output signal in response to an alarm condition for an associated protected area, alarm sensor monitoring means including alarm data storage means including separate alarm output storage means for each of said alarm sensors for storing the alarm output signals provided by the alarm sensors, and alarm transmission means controlled by said alarm storage means in response to the receipt of an alarm output signal provided by at least one of said alarm sensors to effect the readout of said alarm storage means to provide an alarm code for transmission over said transmission line to said central monitor, said alarm code being comprised of a sequence of coded bits in which a first bit indicates that an alarm output has been provided by at least one of the alarm sensors and further bits of the sequence are coded to indicate which alarm sensor Has provided the alarm output, and line monitoring means at said central monitor including means responsive to the first bit of said alarm code to provide an alarm indication at said central monitor and means responsive to said further bits of said alarm code to determine the source of the alarm.

Claim 4

In a security system including a transmission line for carrying alarm information from a plurality of protected areas to a central monitor that is remote from the protected areas, alarm source means including an individual alarm sensor for each protected area, each of said alarm sensors being operable to provide an alarm output signal in response to an alarm condition for an associated protected area, alarm sensor monitoring means including alarm data storage means including separate alarm output storage means for each of said alarm sensors for storing the alarm output signals provided by the alarm sensors, and alarm transmission means controlled by said alarm storage means in response to the receipt of an alarm output signal provided by at least one of said alarm sensors to effect the readout of said alarm storage means to provide an alarm code for transmission over said transmission line to said central monitor, said alarm code being comprised of a sequence of coded bits in which a first bit indicates that an alarm output has been provided by at least one of the alarm sensors and further bits of the sequence are coded to indicate which alarm sensor Has provided the alarm output, and line monitoring means at said central monitor including means responsive to the first bit of said alarm code to provide an alarm indication at said central monitor and means responsive to said further bits of said alarm code to determine the source of the alarm.

Claim 5

A system as set forth in claim 2 wherein each of said alarm sensors are further operable to provide a supervisory alarm output signal in response to a component failure of the alarm sensor, and wherein said alarm storage means further includes separate supervisory storage means for each of said alarm sensors for storing supervisory alarm outputs provided by the alarm sensors, said alarm transmission means being responsive to either an alarm output signal or a supervisory output signal to provide an alarm code for transmission to said central monitor.

Claim 6

A system as set forth in claim 3 wherein each of said alarm output storage means comprises a first normally reset bistable data storage circuit and each of said supervisory storage means comprises a second normally reset bistable data storage circuit, a first data storage circuit being set whenever an alarm output signal is provided by an associated alarm sensor and a second data storage circuit being set whenever a supervisory alarm output signal is provided by an associated alarm sensor.

Claim 7

A system as set forth in claim 4 wherein said readout means includes means for resetting all of the bistable data storage circuits of said alarm storage means after said alarm code has been transmitted to said central monitor.

Claim 8

In a security system including a transmission line for carrying alarm information from a plurality of protected areas to a central monitor that is remote from the protected areas, alarm source means including an individual alarm sensor for each protected area, each of said alarm sensors being operable to provide an alarm output signal in response to an unauthorized intrusion of an associated area, alarm sensor monitoring means including alarm storage means having an individual bistable storage means for each alarm sensor settable to a first state in response to the receipt of an alarm output signal provided by an associated alarm sensor, code generating means for continuously generating a line monitoring code comprised of a known sequence of code bits for transmission over said transmission line to said central monitor, and readout means including means controlled by said alarm storage means in response to the receipt of an alarm output signal provided by one of said alarm sensors to selectively modify bits of the line monitoring code sequence to provide a modified code sequence in which the first bit of the modified sequence represents an alarm indication and subsequent bits of the modified sequence of bits represent the conditions of the alarm sensors, and means for resetting said storage means after the modified code sequence has been provided.

Claim 9

In a security system including a transmission line for carrying alarm information from a plurality of protected areas to a central monitor that is remote from the protected areas, alarm source means including an individual alarm sensor for each protected area, each of said alarm sensors being operable to provide an alarm output signal in response to an unauthorized intrusion of an associated area, alarm sensor monitoring means including alarm storage means having an individual bistable storage means for each alarm sensor settable to a first state in response to the receipt of an alarm output signal provided by an associated alarm sensor, code generating means for continuously generating a line monitoring code comprised of a known sequence of code bits for transmission over said transmission line to said central monitor, and readout means including means controlled by said alarm storage means in response to the receipt of an alarm output signal provided by one of said alarm sensors to selectively modify bits of the line monitoring code sequence to provide a modified code sequence in which the first bit of the modified sequence represents an alarm indication and subsequent bits of the modified sequence of bits represent the conditions of the alarm sensors, and means for resetting said storage means after the modified code sequence has been provided.

Claim 10

In a security system including a transmission line for carrying alarm information from a plurality of protected areas to a central monitor that is remote from the protected areas, alarm source means including an individual alarm sensor for each protected area, each of said alarm sensors being operable to provide an alarm output signal in response to an unauthorized intrusion of an associated area, alarm sensor monitoring means including alarm storage means having an individual storage means for each alarm sensor for storing the alarm output signals provided by the corresponding alarm sensor, code generating means for continuously generating a line monitoring code comprised of a known sequence of coded bits, bit gating means for passing the bits of the line monitoring code to said transmission line for transmission to said central monitor, and readout means controlled by said alarm storage means in response to the receipt of an alarm output signal provided by an alarm sensor to effect readout of said alarm storage means thereby providing a sequence of alarm data bIts and to enable said bit gating means to be responsive to said sequence of alarm data bits to modify a bit of the line monitoring code to indicate that an alarm output signal has been provided by at least one of said alarm sensors and to thereafter selectively modify further bits of the line monitoring code to identify the source of the alarm, and line monitoring means at said central monitor including reference code generating means for generating a reference code comprised of a sequence of coded bits, each bit of which is normally identical with corresponding bits of the line monitoring code at any given time, code comparator means for receiving the bits of the line monitoring code and comparing the monitor code bit sequence with the reference code bit sequence, first means controlled by said code comparator means for providing an alarm indication whenever corresponding bits of the sequence are different, and second means responsive to said further bits of said alarm code to determine the source of the alarm.

Claim 11

In a security system including a transmission line for carrying alarm information from a plurality of protected areas to a central monitor that is remote from the protected areas, alarm source means including an individual alarm sensor for each protected area, each of said alarm sensors being operable to provide an alarm output signal in response to an unauthorized intrusion of an associated area, alarm sensor monitoring means including alarm storage means having an individual storage means for each alarm sensor for storing the alarm output signals provided by the corresponding alarm sensor, code generating means for continuously generating a line monitoring code comprised of a known sequence of coded bits, bit gating means for passing the bits of the line monitoring code to said transmission line for transmission to said central monitor, and readout means controlled by said alarm storage means in response to the receipt of an alarm output signal provided by an alarm sensor to effect readout of said alarm storage means thereby providing a sequence of alarm data bIts and to enable said bit gating means to be responsive to said sequence of alarm data bits to modify a bit of the line monitoring code to indicate that an alarm output signal has been provided by at least one of said alarm sensors and to thereafter selectively modify further bits of the line monitoring code to identify the source of the alarm, and line monitoring means at said central monitor including reference code generating means for generating a reference code comprised of a sequence of coded bits, each bit of which is normally identical with corresponding bits of the line monitoring code at any given time, code comparator means for receiving the bits of the line monitoring code and comparing the monitor code bit sequence with the reference code bit sequence, first means controlled by said code comparator means for providing an alarm indication whenever corresponding bits of the sequence are different, and second means responsive to said further bits of said alarm code to determine the source of the alarm.

Claim 12

A system as set forth in claim 7 wherein each storage means comprises an alarm flip flop, each alarm flip flop being normally reset to provide an output bit at a first logic level and being set in response to an alarm output signal provided by an associated alarm sensor to provide an output bit at a second logic level.

Claim 13

A system as set forth in claim 8 in which said readout means includes multistage shift register means having an individual stage for each alarm flip flop of said alarm storage means, means for extending the output bits provided by different alarm flip flops to a different stage of the shift register means, and means for extending a bit at said second logic level to a further stage of said shift register means whereby said shift register means stores alarm data including data representing the conditions of all of the alarm sensors.

Claim 14

A system as set forth in claim 9 wherein said readout means includes readout control means responsive to an output bit at said second logic level provided by at least one of said alarm flip flops to provide a plurality of gated clock pulses for said shift register means for effecting the serial readout of the data bits stored therein thereby providing said sequence of alarm data bits at the output of said shift register means.

Claim 15

A system as set forth in claim 10 wherein said bit gating means includes means responsive to each data bit at said second logic level read out of said shift register means to complement a bit of the line monitoring code.

Claim 16

A system as set forth in claim 10 wherein said readout control means includes means for generating clock pulses for controlling said code generating means to generate code bits at a predetermined rate, and clock pulse gating means operable when enabled to gate said clock pulses to said shift register means to effect the serial readout of the bits stored therein in synchronism with the generation of the code bits of the line monitoring code, and enabling means responsive to an alarm output signal provided by at least one of said alarm sensors to enable said clock pulse gating means.

Claim 17

A system as set forth in claim 12 wherein said bit gating means includes Exclusive OR gating means having a first input connected to receive the bits of the line monitoring code generated by said code generating means and a second input connected to receive the bits of the alarm code read out of said identification data storage register, and control gating means enabled by said enabling means to pass the bits of the alarm code to the second input of said Exclusive OR gating means, said Exclusive OR gating means being responsive to each bit of the alarm code read out of the shift register which is at the first logic level to pass a code bit of the line monitoring code unaltered to the transmission line and responsive to each bit of the alarm code read out of the shift register which is at the second logic level to complement a code bit of the line monItoring code as such code bit is passed to the transmission line.

Claim 18

A system as set forth in claim 12 in which said readout control means includes reset means for resetting the alarm flip flops after the alarm code has been transmitted to the central monitor.

Claim 19

A system as set forth in claim 14 wherein said reset means includes means for disabling said clock pulse gating means after a predetermined number of clock pulses have been extended to said shift register means.