Dual tone selector with answerback signalling

Claim 2

An answerback signaling arrangement for an audio tone selector system, in which function control codes of selected tones are transmitted from a control location to operate selected functions at remote stations, comprising in combination at each station, a. a filter, amplifier network tuned for receiving function control tones only within the range transmitted from said control location, b. a registry means connected to said filter, amplifier network and responsive to received tone codes for producing output pulses to control the selected function only when the received code is one assigned to the station functions, c. feedback circit means coupled to said filter, amplifier network and also connected for receiving said registry means output pulses and enabled thereby for completing at least one feedback circuit for said filter, amplifier network for generating an answerback signal within the range of the audio function control tones, and d. said filter, amplifier network coupled for transmitting each answerback tone to said control location to indicate registry of the corresponding function control code.

Claim 3

An answerback signaling arrangement as defined in claim 1, in which the filter, amplifier network includes, a. at least one bandpass filter and compression amplifier circit path tuned to a preselected frequency band including the audio tones transmitted from the control office, b. an analog switch connected to be enabled by an output pulse of said registry means when a function control code is registered, c. a feedback circuit for said filter, amplifier circuit controlled by said analog switch to be completed when the switch is enabled, d. said filter, amplifier circuit path tuned by the completed feedback circuit to oscillate at a preselected frequency within the audio range of the filter pass band for generating an answerback signal, e. said filter, amplifier, feedback circuit network coupled for transmitting each answerback signal to said control location to indicate the registry of a transmitted code.

Claim 4

An answerback signaling arrangement as defined in claim 2 in which, the frequency to which said filter, amplifier, feedback circuit network is tuned is the center frequency of the pass band of the filter.

Claim 5

An answerback signaling arrangement as defined in claim 1, in which said filter, amplifier network comprises, a. a first and a second bandpass filter and compression amplifier circuit path, each individually tuned to a preselected frequency band within the audio range transmitted from the control location, b. a first and a second analog switch associated with said first and second filter, amplifier circuit paths, respectively, each connected to be enabled by a first and a second output pulse, respectively, produced by said registry means, when a first or a second type code is received, c. a feedback circuit associated with each filter, amplifier circuit path and controlled by the associated analog switch to be completed when that switch is enabled,

Claim 6

each associated filter, amplifier, feedback circuit network tuned by the completed feedback circuit for oscillating at a preselected frequency within the corresponding filter bandpass range to generate a signal when a corresponding received function code is registered, d. each filter, amplifier, feedback circuit network coupled for transmitting each generated signal as an answerback signal to said control location to indicate registry of the corresponding transmitted function control code.

Claim 7

each associated filter, amplifier, feedback circuit network tuned by the completed feedback circuit for oscillating at a preselected frequency within the corresponding filter bandpass range to generate a signal when a corresponding received function code is registered, d. each filter, amplifier, feedback circuit network coupled for transmitting each generated signal as an answerback signal to said control location to indicate registry of the corresponding transmitted function control code.

Claim 8

An answerback signaling arrangement as defined in claim 4 in which, the frequency to which each filter, amplifier, feedback circuit network is tuned is the center frequency of the pass band of the corresponding filter.

Claim 9

Selector apparatus for use at a remote station in a telephone selector system, in which codes including a preselected plurality of signals in a selected sequence are individually transmitted from a control location to control functions at remote stations, each transmitted signal comprising a pair of audio frequency tones, comprising in combination, a. a tone decoder element, including at least one bandpass filter and compression amplifier circuit path tuned to a preselected frequency band including the audio frequency tones comprising the function control signals, connected for receiving the code sequence of transmitted dual tone signals and responsive thereto for producing an output sequence of pairs of logic signals representing the tones received, b. a code selector element connected for receiving logic signals from said tone decoder element and operable for decoding the received sequence to produce a functon control pulse if the received signal sequence is identical to that assigned to a function at that station, c. a function control means connected for receiving each control pulse from said code selector element and responsive thereto for operating the function in the desired manner in accordance with the code transmitted, d. a first analog switch associated with said filter, amplifier circuit path of said tone decoder element and connected to be enabled by the pulse produced by said code selector element, and e. a feedback circuit for said filter, amplifier circuit path controlled by said analog switch to be completed when the switch is enabled, f. said filter, amplifier circuit path tuned by the completed feedback circuit to oscillate at a preselected frequency within the audio range of the filter pass for generating an answerback signal, g. said filter, amplifier, feedback circuit network coupled for transmitting each answerback signal to said control location to indicate the registry of the corresponding transmitted code.

Claim 10

Selector apparatus for use at a remote station in a telephone selector system, in which codes including a preselected plurality of signals in a selected sequence are individually transmitted from a control location to control functions at remote stations, each transmitted signal comprising a pair of audio frequency tones, comprising in combination, a. a tone decoder element, including at least one bandpass filter and compression amplifier circuit path tuned to a preselected frequency band including the audio frequency tones comprising the function control signals, connected for receiving the code sequence of transmitted dual tone signals and responsive thereto for producing an output sequence of pairs of logic signals representing the tones received, b. a code selector element connected for receiving logic signals from said tone decoder element and operable for decoding the received sequence to produce a functon control pulse if the received signal sequence is identical to that assigned to a function at that station, c. a function control means connected for receiving each control pulse from said code selector element and responsive thereto for operating the function in the desired manner in accordance with the code transmitted, d. a first analog switch associated with said filter, amplifier circuit path of said tone decoder element and connected to be enabled by the pulse produced by said code selector element, and e. a feedback circuit for said filter, amplifier circuit path controlled by said analog switch to be completed when the switch is enabled, f. said filter, amplifier circuit path tuned by the completed feedback circuit to oscillate at a preselected frequency within the audio range of the filter pass for generating an answerback signal, g. said filter, amplifier, feedback circuit network coupled for transmitting each answerback signal to said control location to indicate the registry of the corresponding transmitted code.

Claim 11

Selector apparatus as defined in claim 6 in which, the frequency to which said filter, amplifier, feedback circuit network is tuned is the center frequency of the pass band of the filter.

Claim 12

Selector apparatus as defined in claim 6 in which, a. said code selector element produces a first or a second function control pulse as a first or a second assigned code sequence is received at the corresponding station, and which also includes, b. a second bandpass filter and compression amplifier circuit path, each such circuit path individually tuned to a different preselected frequency band within the range of the audio frequency tones transmitted from said control location, c. a second analog switch associated with said second filter, amplifier circuit path, said first and second switches connected to be enabled by said first and second pulses, respectively, produced by said code selector element, d. another feedback circuit associated with said second filter, amplifier circuit path and controlled by the second analog switch to be completed when that switch is enabled, 1. each associated filter, amplifier, feedback circuit network tuned by the completed feedback circuit for oscillating at a preselected frequency within the bandpass range of the corresponding filter to generate a signal when the corresponding pulse is produced by said code selector element, e. each filter, amplifier, feedback circuit network coupled for transmitting each generated signal as an answerback indication to said control location that the corresponding function control code has been registered.

Claim 13

Selector apparatus as defined in claim 8 in which, the frequency to which each filter, amplifier, feedback circuit network is tuned is the center frequency of the pass band of the corresponding filter.