Automatic telephone answering apparatus

Claim 2

In an automatic telephone answering apparatus coupled to a called side telephone set to operate cooperatively therewith and operating in response to the arrival of a call signal sent by a caller through a telephone line to send an answering message to the caller side, the combination of: a first control circuit operating in response to a call signal which has arrived through a telephone line said signal being of the kind having the same recurrent period in which the duration of the ringing portion thereof may vary between different telephone systems to produce output pulses of the same period as those of said call signal and of a constant pulse width irrespective of the kind of call signal; and a second control circuit operating upon being supplied with a predetermined number of the pulses from the first control circuit to place the apparatus in the answering state of operation thereof by sending said answering message.

Claim 3

An automatic telephone answering apparatus as claimed in claim 1 in which the first control circuit comprises a differentiating circuit operating in response to the arrival of the call signal to produce an output signal including positive pulses and a pulse signal circuit operating in response to said positive pulses to produce as output pulse signals of a predetermined pulse width.

Claim 4

An automatic telephone answering apparatus as claimed in claim 2 in which the pulse signal circuit for producing pulse signals of a predetermined pulse width is a one-shot multivibrator triggered by the output signal of the differentiating circuit.

Claim 5

An automatic telephone answering apparatus as claimed in claim 1 in which the second control circuit comprises a charging and discharging circuit charged by the pulse signals from the first control circuit and discharging during the periods when the pulse signals are not applied thereto, and a circuit operating when the charging and discharging circuit has been charged to a predetermined voltage to place the apparatus in the answering state.

Claim 6

An automatic telephone answering apparatus as claimed in claim 4 in which the charging and discharging time constants of the charging and discharging circuit are so selected in relation to the pulse width of the pulse signals from the first control circuit that, as the pulse signals are successively applied to the charging and discharging circuit, which thereupon undergoes repeated charging and discharging, the charging voltage progressively increases.

Claim 7

An automatic telephone answering apparatus as claimed in claim 1 in which there is further provided cut off means for cutting off the arrival of the call signal with respect to the first control circuit when, during the operation of answering a call, the receiver of the called side telephone is lifted off its cradle thereby to close the telephone line for the apparatus, and the first control circuit is rendered inoperative by the cutting off of the arrival of the call signal by the cut off means and thereby does not permit the second control circuit to operate.

Claim 8

An automatic telephone answering apparatus as claimed in claim 4 in which there is further provided cut off means for cutting off the arrival of the call signal with respect to the first conTrol circuit when, during the operation of answering a call, the receiver of the called side telephone is lifted off its cradle thereby to close the telephone line for the apparatus, and the first control circuit is rendered inoperative by the cutting off of the arrival of the call signal by the cut off means and does not produce pulse signals as output, whereby the charging and discharging circuit continues discharging and does not operate the second control circuit.

Claim 9

An automatic telephone answering apparatus as claimed in claim 4 in which the charging and discharging circuit further has charging time constant variable means which, by adjustment of the charging time constant thereof, adjusts the number of call signals required for operating the circuit for placing the apparatus in the answering state.

Claim 10

In automatic telephone answering apparatus coupled to called end of a telephone line to which a telephone set is attached and operating in response to the arrival of a recurring intermittant ringing signal on said line sent by a caller for a predetermined period and thereafter for transmitting an answering message to the caller if said telephone set has not been yet answered manually by a called party, the combination including: a first control circuit coupled to respond to the arrival of a recurring intermittant ringing signal having a predetermined fixed period and a duration which may vary with different telephone systems to provide control pulses of the same period as said ringing signal and of a predetermined fixed pulse width; and a second control circuit connected to receive said control pulses for connecting said answering apparatus to said line and thereupon transmitting said answering message to said caller after receiving a predetermined number of said pulses in an uninterrupted series.

Claim 11

In automatic telephone answering apparatus coupled to called end of a telephone line to which a telephone set is attached and operating in response to the arrival of a recurring intermittant ringing signal on said line sent by a caller for a predetermined period and thereafter for transmitting an answering message to the caller if said telephone set has not been yet answered manually by a called party, the combination including: a first control circuit coupled to respond to the arrival of a recurring intermittant ringing signal having a predetermined fixed period and a duration which may vary with different telephone systems to provide control pulses of the same period as said ringing signal and of a predetermined fixed pulse width; and a second control circuit connected to receive said control pulses for connecting said answering apparatus to said line and thereupon transmitting said answering message to said caller after receiving a predetermined number of said pulses in an uninterrupted series.