Signaling system utilizing frequency and frequency duration for signaling and control functions

Claim 2

A signaling system for transmitting state information along signal transmission means comprising, central station means connected to said signal transmission means for applying an interrogation signal including at least a first tone pulse of predetermined characteristics to said signal transmission means for transmission thereby, for detecting from said signal transmission means at least a second tone pulse of predetermined characteristics different from said first tone pulse, and for producing a central station activation signal upon such detection; utilization circuit means connected to said central station means and disposable in a predetermined state in response to said central station activation signal; monitor means disposable in a characteristic state; and remote station means connected to said signal transmission means and monitor means for detecting said first tone pulse from said signal transmission means, for producing a remote station activation signal upon such detection, and for applying to said signal transmission means for transmission thereby a state signal including at least said second tone pulse in response to said remote station activation signal and said characteristic monitor means state, said central station means and remote station means each including decoder means for detecting the predetermined characteristics of said second and first tone pulses respectively, said decoder means each having filter means for producing a tone pulse of at least one predetermined frequency and detector means for comparing the width of tone pulses with A reference, whereby said utilization circuit means is disposed in a state representative of said characteristic monitor means state.

Claim 3

A signaling system as claimed in claim 1, wherein said monitor means is disposable in a plurality of characteristic states, said remote station means being adapted to generate a plurality of second tone pulses each having predetermined characteristics different from the characteristics of the other of said second tone pulses and each being associated with one of said characteristic monitor means states, said remote station means selectively applying to said signal transmission means in response to said remote station activation signal the second tone pulse associated with the characteristic state in which said monitor means is disposed, said central station means being further adapted to produce a characteristic central station activation signal upon detection of each of said second tone pulses, said utilization circuit means being disposable in a distinctive state in response to each of said characteristic central station activation signals each representative of a characteristic monitor means state.

Claim 4

A signaling system as claimed in claim 1, including a plurality of remote station means each connected to said signal transmission means and a monitor means connected to each of said remote station means, said central station means being adapted to generate a plurality of first tone pulses each having a predetermined characteristic different from the other of said first tone pulses, one of said first tone pulses being associated with each of said plurality of remote station means, each of said remote station means being adapted to detect its associated first tone pulse for producing a remote station activation signal in response thereto, said central station means being further adapted to produce a characteristic central station activation signal upon detection of the second tone pulse of each remote station means, said utilization circuit means being disposable in a plurality of predetermined states in response to said characteristic central station activation signals each representative of the state of a respective monitor means.

Claim 5

A signaling system as claimed in claim 3, wherein said central station means produces an interrogation signal including a sequential series of said first tone pulses, each of said first tone pulses being followed by a time delay sufficient to permit the interleaved transmission of the state signal of the remote station means associated therewith.

Claim 6

A signaling system as claimed in claim 3, wherein said signal transmission means includes a line interconnecting said plurality of remote station means in series connection and interconnecting said central station means and said plurality of series-connected, remote station means, each of said central station means and remote station means being AC coupled with said transmission line.

Claim 7

A signaling system as claimed in claim 1, wherein said signal transmission means includes a line interconnecting said central station means and said remote station means, said central station means and remote station means being AC coupled to said line.

Claim 8

A central station for actuating utilization circuit means to reflect the state of monitor means disposed at a plurality of remote locations in response to state signals therefrom comprising, generating means for transmitting to said remote locations an interrogation signal to cause the transmission of said state signals, said interrogation signal including a plurality of first tone pulses each having a predetermined characteristic different from the other of said first tone pulses, one of said first tone pulses being associated with each of said plurality of remote locations; decoder means for producing a central station activation signal upon detecting, in said state signals, at least a second tone pulse of predetermined characteristics different from said first tone pulses, said second tone pUlse being associated with a characteristic state of said monitor means, said decoder means having filter means for passing a tone pulse of at least one predetermined frequency and detector means for comparing the width of tone pulses with a reference; and control means connected to said decoder means for receiving said activation signal and to said utilization circuit means for disposing said utilization circuit means in a state representative of the state of said monitor means in response to said activation signal.

Claim 9

A central station for actuating utilization circuit means to reflect the state of monitor means disposed at a plurality of remote locations in response to state signals therefrom comprising, generating means for transmitting to said remote locations an interrogation signal to cause the transmission of said state signals, said interrogation signal including a plurality of first tone pulses each having a predetermined characteristic different from the other of said first tone pulses, one of said first tone pulses being associated with each of said plurality of remote locations; decoder means for producing a central station activation signal upon detecting, in said state signals, at least a second tone pulse of predetermined characteristics different from said first tone pulses, said second tone pUlse being associated with a characteristic state of said monitor means, said decoder means having filter means for passing a tone pulse of at least one predetermined frequency and detector means for comparing the width of tone pulses with a reference; and control means connected to said decoder means for receiving said activation signal and to said utilization circuit means for disposing said utilization circuit means in a state representative of the state of said monitor means in response to said activation signal.

Claim 10

A central station as recited in claim 7, wherein said generator means includes a plurality of sequentially activated pulse generators each adapted to produce a pulse of a width different from the pulses produced by the other of said pulse generators; and an oscillator of a predetermined frequency connected to said pulse generators for firing by the series of pulses received therefrom to produce a series of said first tone pulses.

Claim 11

A central station as recited in claim 8, wherein said generator means includes time delay circuit means for incorporating in said interrogation signal, at least once during each cycle of said plurality of pulse generators, a time delay of predetermined duration associated with each of said remote locations, said decoder means detecting the state signal from each remote station during the time delay associated therewith.

Claim 12

A central station as claimed in claim 9, wherein said pulse generators are serially connected in a ring counter configuration, said time delay circuit means including a time delay circuit associated with each remote location disposed in said series connection immediately following the pulse generator associated with said remote location for delaying the activation of the next sequential pulse generator for said predetermined duration.

Claim 13

A central station as claimed in claim 10, wherein said time delay circuits are connected to said control means and adapted to produce a time delay gating signal during the operation thereof for application to said control means, said control means disposing said utilization circuit means in a state representative of the state of each monitor means of each remote location in response to said time delay gating signal and said central station activation signal.

Claim 14

A central station as claimed in claim 7, wherein said decoder means includes filter means for passing only a tone pulse of a predetermined tone frequency; DC switch means for producing a square wave pulse of a width equal to the width of said passed tone pulse; and detector means for comparing said square wave pulse with a reference to produce an activation signal only if said square wave pulse is of a width equal to the width of said second tone pulse.

Claim 15

A central station as claimed in claim 12, wherein said detector means includes first circuit means for producing a first output responsive to said square wave pulse at a time corresponding to the trailing edge of said second tone pulse if said square wave pulse is of a width equal to or greater than said second tone pulse; second circuit means for producing a second output at the time corresponding to the trailing edge of said square wave pulse; and gate means for producing said central station activation signal upon the coincidence of said first and second outputs.

Claim 16

A central station as claimed in claim 12, including a plurality of detector means each adapted to produce a characteristic central station activation signal upon the application thereto of a square wave pulse of a width equal to one of a plurality of second tone pulses, each of said second tone pulses being of a width different from the width of the other of said second tone pulses and being associated with a characteristic state of said monitor means, said control means being responsive to each of said characteristic central station activation signals to dispose said utilization circuit means in a corresponding state.

Claim 17

A central station as claimed in claim 7, inclUding missing indicator means for receiving said state signal and for applying a missing indicator activation signal to said control means in the absence of a second tone pulse from any of said remote locations, said control means being adapted to dispose said utilization circuit means in a state reflecting such lack of state signal in response to said missing indicator activation signal.

Claim 18

A remote station for transmission of a signal representative of the state of monitor means associated therewith to a central location in response to an interrogation signal including at least a first tone pulse having predetermined tone frequency and width received therefrom comprising, filter means for receiving said interrogation signal and passing only tone pulses of said predetermined tone frequency; detector means for producing a remote station activation signal in response to a passed tone pulse of said predetermined width; and state signal generator means connected to said monitor means for producing a state signal including at least a second tone pulse having predetermined characteristics different from said first tone pulse and associated with a monitor means state for transmission to said central location.

Claim 19

A remote station for transmission of a signal representative of the state of monitor means associated therewith to a central location in response to an interrogation signal including at least a first tone pulse having predetermined tone frequency and width received therefrom comprising, filter means for receiving said interrogation signal and passing only tone pulses of said predetermined tone frequency; detector means for producing a remote station activation signal in response to a passed tone pulse of said predetermined width; and state signal generator means connected to said monitor means for producing a state signal including at least a second tone pulse having predetermined characteristics different from said first tone pulse and associated with a monitor means state for transmission to said central location.

Claim 20

A remote station as claimed in claim 16, wherein said state signal generator means is adapted to selectively produce any one of a plurality of second tone pulses each having characteristics different from the other of said second tone pulses and each representative of a different state of said monitor means.

Claim 21

A remote station as claimed in claim 17, wherein said state pulse generator means includes bistable circuit means for producing an output signal beginning upon the activation thereof by said remote station activation signal and continuing until the resetting thereof by a reset signal to define a pulse; time delay circuit means connected to said bistable circuit means, said time delay circuit means being activated by said output signal and producing said reset signal after a time delay of a predetermined duration, said time delay circuit means including means for selectively adjusting the duration of said time delay in response to the state of said monitor means; and oscillator means connected to said bistable circuit means for firing in response to said output signal to produce said second time pulses.

Claim 22

A remote station as recited in claim 18, wherein said time delay circuit means includes RC charging circuit means for receiving the output of said bistable circuit means, said means for selectively adjusting the duration of said time delay being adapted to selectively adjust the value of the resistance of said RC charging circuit means to any one of a plurality of resistance values each associated with one of said monitor means states, said RC charging circuit means including a capacitor; and switch means connected to said capacitor for applying said reset signal to said bistable circuit means when the voltage across said capacitor reaches a predetermined value.

Claim 23

A remote station as claimed in claim 16, wherein said detector includes DC switch means for producing a square wave pulse of a width equal to the width of the tone pulse passed by said filter means; first circuit means for producing a first output responsive to said square wave pulse at a time corresponding to the trailing edge of said first tone pulse if said square wave pulse is of a width equal to or greater than said first tone pulse; second circuit means for producing a second output at the time corresponding to the trailing edge of said square wave pulse; and gate means for producing said remote station activation signal upon the coincidence of said first and second outputs.

Claim 24

A central station alarm system for transmitting information representative of the state of alarm means disposed at a plurality of remote locations along signal transmission means comprising, central station means connected to said signal transmission means for applying thereto an interrogation signal including a plurality of first tone pulses each having predetermined characteristics different from the other of said first tone pulses, one of said first tone pulses being associated with each of said plurality of remote locations, said central station means being adapted to detect from said signal transmission means at least a second tone pulse of predetermined characteristics different from said first tone pulses and to produce a central station activation signal upon such detection; display means connected to said central station means for disposition in a state representative of the state of each of said alarm means in response to said central station activation signal; and a plurality of remote station means each disposed at a remote location and connected to said signal transmission means and an alarm means at said remote location, each of said remote station means being adapted to detect the first tone pulse associated therewith from said signal transmission means, to produce a remote station activation signal upon such detection, and to apply to said signal transmission means for transmission thereby a state signal including at least said second tone pulse in response to said remote station activation signal and the state of said alarm means, said second tone pulse being representative of said alarm means state, said central station means and remote station means each including decoder means for detecting the predetermined characteristics of said second and first tone pulses respectively, said decoder means each having filter means for passing a tone pulse of at least one predetermined frequency and detector means for comparing the width of tone pulses with a reference, whereby said display means reflects the state of each of said alarm means.

Claim 25

A central station alarm system for transmitting information representative of the state of alarm means disposed at a plurality of remote locations along signal transmission means comprising, central station means connected to said signal transmission means for applying thereto an interrogation signal including a plurality of first tone pulses each having predetermined characteristics different from the other of said first tone pulses, one of said first tone pulses being associated with each of said plurality of remote locations, said central station means being adapted to detect from said signal transmission means at least a second tone pulse of predetermined characteristics different from said first tone pulses and to produce a central station activation signal upon such detection; display means connected to said central station means for disposition in a state representative of the state of each of said alarm means in response to said central station activation signal; and a plurality of remote station means each disposed at a remote location and connected to said signal transmission means and an alarm means at said remote location, each of said remote station means being adapted to detect the first tone pulse associated therewith from said signal transmission means, to produce a remote station activation signal upon such detection, and to apply to said signal transmission means for transmission thereby a state signal including at least said second tone pulse in response to said remote station activation signal and the state of said alarm means, said second tone pulse being representative of said alarm means state, said central station means and remote station means each including decoder means for detecting the predetermined characteristics of said second and first tone pulses respectively, said decoder means each having filter means for passing a tone pulse of at least one predetermined frequency and detector means for comparing the width of tone pulses with a reference, whereby said display means reflects the state of each of said alarm means.

Claim 26

A central station alarm system as recited in claim 21, wherein said alarm means are disposable in a plurality of characteristic states, each of said remote station means being adapted to generate a plurality of second tone pulses each having predetermined characteristics different from the characteristics of the other of said second tone pulses and each being associated with one of said characteristic alarm means states, each of said remote station means selectively applying to said signal transmission means in response to said remote station activation signal the second tone pulse associated with the characteristic state in which its alarm means is disposed, said central station means being further adapted to produce a characteristic central station activation signal upon detection of each of said second tone pulses, said display means reflecting the characteristic state in which each of said alarm means are disposed in response to said characteristic central station activation signals.