US 4,064,367 A · Dual tone selector with answerback signalling

Abstract

A function control code sequence of signals, each comprising a pair of audio frequency tones, is transmitted from a control location to a remote station selector. Each input signal is applied to a tone decoder element which separates the two tones through a filter, amplifier, detector network to produce a pair of logic signals representing the tones received. The sequential pairs of logic signals are applied to a code selector which converts the 2 of 7 format into a 1 of 12 digital code sequence equivalent to the original function control code selected at the control location. This digital sequence is applied through a programmable cross bar connector matrix to a sequence detector responsive only to a predetermined input sequence. The matrix is programmed to produce this predetermined sequence and actuate the sequence detector only when an assigned function code is received. When the sequence detector is actuated, its output is applied through another matrix to a pulse generator which produces an output pulse to actuate the desired function control. Each output pulse is also applied to the tone decoder to enable an analog switch which completes a feedback path for one of the input bandpass filter, compression amplifier networks. When the feedback path is complete, the filter, amplifier network oscillates at a preselected audio frequency to transmit an answerback signal to the control location to indicate that the transmitted function has been registered.

Claims9

Dependent claims

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.

1 more element

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.

4 more elements

Dependencies are inferred from the claim text.

Dual tone selector with answerback signalling

Life of this patent

Dual tone selector with answerback signalling

Life of this patent

Abstract

Claims9