Telephone audio signalling arrangement

Claim 2

In a telephone system, audio signalling arrangement comprising: a. an electronic tone-ringer, in a telephone set, which generates a first tone signal at a first audio frequency when supplied with a direct current operating voltage; said toneringer having an electronic oscillator coupled via an audio amplifier to an electro-acoustic transducer, said direct current operating voltage being supplied to power input terminals of the electronic oscillator and the audio amplifier; b. a signalling generator, in common control circuitry, for generating an audio frequency operating voltage at a second audio frequency greater than the first audio frequency of the first tone signal; (c) switching means, in the telephone set, responsive to the audio frequency operating voltage for interrupting the direct current operating voltage being supplied to said tone-ringer at the rate of said second audio frequency, so that the electronic tone-ringer generates a second tone signal at said second audio frequency.

Claim 3

In a telephone system, an audio signalling arrangement comprising: a. an electronic tone-ringer in a telephone set which generates a first tone signal at a first audio frequency when supplied, from a power source, with a direct current operating voltage; said tone-ringer comprising an astable multivibrator coupled via an audio amplifier to an electro-acoustic transducer, said direct current operating voltage being supplied to the power input terminals of the astable multivibrator; b. switch mean, in series with the power source, having a control input, and controllable to interrupt the direct current operating voltage; (c) means for generating a plurality of pulses with a pulse frequency greater than the first audio frequency of the first tone signal, and for connecting said pulses to said control input to control the switch means, whereby the electronic tone-ringer is supplied from the power source, via the switch means, with a pulsating direct current operating voltage to generates a second tone signal at an audio frequency corresponding to the pulse frequency.

Claim 4

In a telephone system, an audio signalling arrangement comprising: a. an electronic tone-ringer in a telephone set which generates a first tone signal at a first audio frequency when supplied, from a power source, with a direct current operating voltage; said tone-ringer comprising an astable multivibrator coupled via an audio amplifier to an electro-acoustic transducer, said direct current operating voltage being supplied to the power input terminals of the astable multivibrator; b. switch mean, in series with the power source, having a control input, and controllable to interrupt the direct current operating voltage; (c) means for generating a plurality of pulses with a pulse frequency greater than the first audio frequency of the first tone signal, and for connecting said pulses to said control input to control the switch means, whereby the electronic tone-ringer is supplied from the power source, via the switch means, with a pulsating direct current operating voltage to generates a second tone signal at an audio frequency corresponding to the pulse frequency.

Claim 5

In a telephone system, an audio signalling arrangement comprising: a. a ringing-code generator for generating sub-sonic ringing signals; b. an electronic tone-ringer which generates a first tone signal at a first audio frequency when supplied with a direct current operating voltage; said tone-ringer comprising an astable multivibrator coupled via an audio amplifier to an electro-acoustic transducer; c. switch means, having a control input, for connecting the electronic tone-ringer to a source of supply voltage in response to a control signal at said control input; d. means for generating a pulse train with a pulse frequency greater than the first audio frequency of the first tone signal; e. means, responsive to a Ringing signal from the ringing-code generator and to said pulse train, for supplying a pulsating control signal to said control input; whereby the electronic tone-ringer is supplied via the switch means with a pulsating operating voltage to generate on an interrupted basis as determined by the ringing signals, a second tone signal at an audio frequency, corresponding to the pulse frequency of the pulse train, and greater than the first audio frequency of the first tone signal.

Claim 6

In a telephone system, an audio signalling arrangement comprising: a. a ringing-code generator for generating sub-sonic ringing signals; b. an electronic tone-ringer which generates a first tone signal at a first audio frequency when supplied with a direct current operating voltage; said tone-ringer comprising an astable multivibrator coupled via an audio amplifier to an electro-acoustic transducer; c. switch means, having a control input, for connecting the electronic tone-ringer to a source of supply voltage in response to a control signal at said control input; d. means for generating a pulse train with a pulse frequency greater than the first audio frequency of the first tone signal; e. means, responsive to a Ringing signal from the ringing-code generator and to said pulse train, for supplying a pulsating control signal to said control input; whereby the electronic tone-ringer is supplied via the switch means with a pulsating operating voltage to generate on an interrupted basis as determined by the ringing signals, a second tone signal at an audio frequency, corresponding to the pulse frequency of the pulse train, and greater than the first audio frequency of the first tone signal.

Claim 7

The audio frequency signalling arrangement as claimed in claim 3 wherein the switch means comprises an electronic switch and the means for supplying the pulsating control signal to said control input comprises a dual input electronic gate.

Claim 8

The invention as claimed in claim 1 wherein the electronic oscillator is an astable multivibrator, and the means for generating an audio frequency operating voltage includes an electronic switch serially connected between the electronic tone-ringer and a direct current supply.