JPS59218055A - Cordless telephone set - Google Patents

Abstract

PURPOSE:To use a call tone as a preliminary bell by preventing an output from appearing by means of a call tone generating circuit driven by an output of a call signal detecting circuit while a timer means is driven with a slight delay from a point of time when a call signal is incoming. CONSTITUTION:A call signal from a trunk line is inputted to a detecting circuit 4, its output drives a delay circuit 28, a timer circuit 29 is driven after a slight time delay, this output is inputted to an AND circuit 30 together with an output of a calling detecting circuit 4 and its output is transmitted from a transmission antenna 12 for a timer set time via a modulation circuit 8 and a power amplifier circuit 10 from a call tone generating circuit 5. This is received by a receiving antenna 14, detected by a call tone detecting circuit 18 via a demodulation circuit 17 and applied to a call tone control circuit 20. Then, the call tone outputted from a speaker 22 is also outputted for a slight time decided by the delay circuit 28 and only at the incoming of call signal after the set time of the timer circuit 29.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a so-called cordless telephone in which a telephone body connected to a central office line and a handset are wirelessly connected.

Conventional Structure and Problems Cordless telephones are generally structured as shown in FIG. In FIG. 1, A is a telephone main body that is connected to a central office line, and B is a handset that is wirelessly connected to the telephone main body A. In FIG. 3 is a voice amplification circuit, 4 is a ringing signal detection circuit, 5 is a ringing tone generation circuit, 6 is a voice amplification circuit, and 7
1 is a line control circuit, 8 is a modulation circuit, 9 is a demodulation circuit, 10 is a power amplification circuit, 11 is a received signal amplification circuit, 12 is a transmission antenna, 13 is a reception antenna, 14 is a reception antenna, 1
5 is a transmitting antenna, 16 is a received signal amplification circuit, 17 is a demodulation circuit, 18 is a ringing detection circuit, 19 is a voice control circuit,
20 is a ringing tone control circuit, 21 is an audio amplification circuit, 22 is a speaker, 23 is a power amplification circuit, 24 is a modulation circuit, 25 is a dial control circuit, 26 is an audio amplification circuit, and 27 is a microphone.

In FIG. 1, when a calling signal comes from the office line as shown in FIG. 2A, this is detected by the calling signal detection circuit 4, and a signal as shown in FIG. 2B is sent to the output terminal of the calling signal detection circuit 4. is output. Figure 2B from the calling signal detection circuit 4
When a signal as shown in FIG.
A signal with a frequency sufficiently higher than the audio frequency as shown in Figure C is output. When the above-mentioned signal is output from the ringing tone generation circuit 5, it is modulated by the modulation circuit 8, and then the signal is modulated by the power amplifier circuit 1.
0 and transmitted via the transmitting antenna 12.

Ringing tone generation circuit 5 transmitted via transmission antenna 12
The output is received by the reception antenna 14 and applied to the demodulation circuit 17 via the reception signal amplification circuit 16. Therefore, the signal is demodulated here and detected by the ring detection circuit 18. When the ringing tone detection circuit 18 detects the above signal, the ringing tone control circuit 2 is activated by its output.
0 is driven, where an audio frequency ringing signal is generated. Then, the output is applied to the speaker 22 via the audio amplification circuit 21, so that the speaker 22 outputs a ringing tone in response to the above output.

When the called party hears the ringing tone from the speaker 22 and drives the dial control circuit 25 to issue a required response signal, the dial control circuit 25, the power amplifier circuit 23, and the transmitting antenna 1
5 to the telephone main body A side. Phone body A
The response signal transmitted to the receiving antenna 13 is received by the receiving antenna 13, applied to the demodulating circuit 9 via the receiving signal amplifying circuit 11, and demodulated there. Therefore, the line control circuit 7 is driven by 1 by the output, and the line connection circuit 1 is turned on. Therefore, in this state, the cordless telephone consisting of the telephone main body and the handset becomes ready to make a call.

During a call, a signal from the office line is applied to the modulation circuit 8 via the line connection circuit 1, hybrid circuit 2, and audio amplification circuit 3, where it is modulated and transmitted via the power amplification circuit 10 and the transmission antenna 12. .

The signal transmitted via the transmitting antenna 2 is received by the receiving antenna 14, demodulated by the demodulation circuit 17,
The signal is applied to the speaker 22 via the audio control circuit 19 and the audio amplification circuit 21.

On the other hand, the microphone 27 signal is transmitted to the audio amplification circuit 26.
The signal is applied to the modulation circuit 24 through the power amplifier circuit 23 and the transmitting antenna 15 after being modulated by the power amplifier circuit 23 and the transmitting antenna 15. The signal from the microphone 27 transmitted via the transmitting antenna 15 is received by the receiving antenna 13, and is decoded eight times by the demodulating circuit 9.
The signal is transmitted to the office line via the hybrid circuit 2 and the line connection circuit 1.

As described above, cordless telephones are conventionally known in which a telephone main body A and a handset B are connected wirelessly so that required calls and conversations can be made. however,
As shown in FIG. 1, all conventional cordless telephones detect a call from a central office line, drive a separately provided ring tone generating circuit 5, and transmit the output to an antenna 12. The ring tone is only transmitted to the handset B side through the receiver B, and if the handset B is placed against the ear by mistake, the ring tone emitted from the speaker 22 that makes up the handset B will be louder. There was a problem in that it caused serious damage to the ears because of its structure. That is, generally speaking, the ringing tone emitted from the speaker 22 needs to be sufficiently audible even when the handset B is placed at a relatively distant position. There is. therefore,
If you mistakenly hold handset B close to your ear in such a case, an excessive ringing sound will hit your ears when a call is received, which will not only cause discomfort but also cause serious damage to your ears. This was not very desirable as there was a possibility of giving.

OBJECT OF THE INVENTION The present invention eliminates the above-mentioned drawbacks of the conventional technology, and has a simple configuration that allows calls to be received with relatively little noise even when the handset is placed in the wrong ear. The purpose of the present invention is to provide an excellent cordless telephone that can detect the following.

Structure of the Invention The present invention provides, in addition to a calling signal detection circuit for detecting a calling signal from a central office line, a timer means that is driven with a slight delay from the time when the above-mentioned calling signal arrives, and this timer means is driven. During this period, the output of the detection circuit prevents the driven ringer generation circuit from outputting the required ringing signal, and after a certain period of time determined by the timer means, the timer means is delayed. The ring tone generating circuit is configured so that the required ring signal is outputted only during the above-mentioned period of time when the ring tone generating circuit is driven.

DESCRIPTION OF THE EMBODIMENT FIG. 3 is a block diagram of an embodiment of the cordless telephone according to the present invention. In the figure, the same reference numerals as in FIG. 1 indicate the same components as in FIG. 1. Further, 28 is a delay circuit that is driven slightly later than the required output from the call detection circuit 4, and 29 is a delay circuit 28.
The timer circuit 30 is driven by the rising edge of the output of the circuit and returns to its original state after a certain period of time, and the reference numeral 30 is an AND circuit which receives the output of the call detection circuit and the output of the timer circuit 29 as inputs.

In the above embodiment, when a calling signal as shown in FIG. 4A arrives from the central office line, it is first detected by the calling detection circuit 4 in the same manner as in the conventional cordless telephone shown in FIG. Therefore, the call detection circuit 4 has the function shown in FIG.
The signal shown in is output. When the call detection circuit 4 outputs a signal as shown in FIG. 4B, the delay circuit 28 is driven by the signal, and the delay circuit 28 is activated after a short time T as shown in FIG. 4C. A predetermined output appears at the output end. Since this output is applied to the timer circuit 29, the timer circuit 29 is driven by the above output, and the level of the output terminal of the quemer circuit 29 is low level for a predetermined period of time T2 as shown in the fourth diagram. become. The output of the timer circuit 29 obtained in this way is combined with the output of the ringing signal detection circuit 4 to an AND circuit 30.
Therefore, a signal as shown in FIG. 4E is outputted to the output terminal of the AND circuit 30. That is, according to the embodiment described above, a predetermined output appears at the output terminal of the AND circuit 30 only when the calling signal arrives after a short time T determined by the delay circuit 28 and a fixed time determined by the timer circuit 29. Therefore, the required ringing tone signal is outputted from the ringing tone generating circuit 5 only at this timing as shown in FIG. 4F. Then, the output from the ring tone generation circuit 5 is modulated by a modulation circuit 8 in the same way as in the conventional cordless telephone shown in FIG. sent to the side.

The signal transmitted to the handset B side is received by the receiving antenna 14 in the same way as in the conventional cordless telephone shown in FIG. It is applied to the control circuit 20. Therefore, an audio frequency calling signal is generated according to the output of the detection circuit 18, and this is applied to the speaker 22 via the audio amplification circuit 21. Therefore, the ringing tone emitted from the speaker 22 is only emitted when the ringing signal arrives after a short time T1 determined by the delay circuit 28 and a certain period of time determined by the timer circuit 29 has elapsed. Therefore, even if you mistakenly put the handset to your ear, the first ringing tone that is emitted will only last for a short time T1 determined by the delay circuit 28, and there will be very little damage to your ears. You can use the ringing tone as a warning bell to quickly move the handset away from your ear. In the above embodiment, after hearing the ringing tone from the speaker 22, the dial control circuit 25 is driven and the line connection circuit is activated. The operations up to turning on the line connection circuit 1 and the operations with the line connection circuit 1 on are exactly the same as those of the conventional cordless telephone shown in FIG. 1, and therefore detailed explanation thereof will be omitted.

Effects of the Invention As is clear from the above embodiments, the present invention provides a timer means that is driven with a slight delay from the time when a calling signal arrives, and when the timer means is in operation, the timer is driven by the output of the calling signal detection circuit. The ring tone generation circuit is constructed so that no output appears, and when a ring signal arrives, the ring tone is first emitted for a short period of time until the timer means is activated. Even if it is large, it does not bother the ear, and even if the handset is placed against the ear, the effect on the ear is extremely small, and the handset can be quickly moved away from the ear using this as a warning bell. and,
Even if the handset is located far from the user's ear, the subsequent ringing tone continues for a relatively long period of time, just like in the past, and has the advantage that the called party can be reliably called.

In the embodiment, the AND circuit 30 is used to control the timer circuit 2.
9 prevents the output of the ringing detection circuit 4 from being applied to the input terminal of the ringing tone generation circuit 5 for a certain period of time T2. It is also possible to make the ring tone generation circuit 5 inactive or to prevent the output of the ring tone generation circuit 5 from being applied to the modulation circuit 8.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional cordless telephone, FIG. 2 is an explanatory diagram of the operation of the main parts, FIG. 3 is a block diagram of an embodiment of the cordless telephone of the present invention, and FIG. 4 is a summary of the same embodiment. FIG. 1...Line connection circuit, 2...Hybrid circuit, 3.
6.21.26... Audio amplification circuit, 4... Ringing signal detection circuit, 5... Ringing tone generation circuit, 7... Line control circuit, 8.24... Modulation circuit, 9.17. ... Demodulation circuit, 10.23 ... Power amplifier circuit, 11.16 ... Received signal amplification circuit, I2.15-- Transmission antenna, 13,
I4... Receiving antenna, 18-... Ringing detection circuit, 1
9...Audio control circuit, 20 Ringing tone control circuit, 22...
Speaker, 25...Dial control circuit, 27 Microphone, 28...Delay circuit, 29 - Timer circuit, 3
0...AND circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure] - Otsuichi 1" Itto L - 11 - 11 - 1 - 1211" 2 Figure 2 Go (A)' (B) (C-)

Claims (1)

[Claims] A calling signal detection circuit for detecting a calling signal from a central office line, and a timer means that is driven with a slight delay from the time when the above-mentioned calling signal arrives, are provided, and while the timer means is being driven, the above-mentioned detection circuit A required ringing signal is outputted from a ringing tone generation circuit driven by the output, and only after the elapse of the above-mentioned time period determined by the above-mentioned timer means and the above-mentioned time period until the above-mentioned timer means is driven. A cordless telephone configured such that the above-mentioned necessary ringing signal is outputted from the above-mentioned ringing tone generating circuit.