JPH0160981B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a wireless telephone that performs a telephone conversation between a base unit connected to a telephone line and a portable handset, in which the base unit is connected to a telephone line. The present invention relates to a radio telephone that notifies a user of a dial tone when a dial pulse signal is generated in a state where a telephone conversation is possible via a radio telephone. (B) Prior art In general, in a wireless telephone, when a key button of a handset is operated to generate a dial pulse signal,
In order to recognize that the key button has been pressed correctly, a dial tone is generated each time the key button is pressed, so the operator listens to this dial tone and accurately sends the dial pulse signal to the base unit. You can confirm that it has been sent. However, since the generation of the dial tone is made independent of the base unit,
The dial pulse signal is not always received by the base unit. Therefore, the operator does not know that the dial pulse signal is not being received by the base unit, and after all the key button operations for the other party's telephone number are completed and the dial pulse signal is transmitted, the telephone line is connected and the other party's calling signal is received. You cannot confirm that the dial pulse signal has been received by the base unit until you hear it through the speaker. Therefore, not only does the operator feel anxious during this time, but if the dial pulse signal is not received by the base unit, the time is completely wasted. (c) Purpose The present invention generates a dial tone only when a dial pulse signal is generated when a call is possible from the slave unit through the base unit, and allows the operator to immediately receive the dial pulse signal on the base unit. This is to let you know what is happening. (d) Configuration In order to achieve the above object, the present invention causes the base unit to generate a carrier wave signal when the base unit receives a carrier wave signal generated by operating the slave unit, and further transmits the carrier wave signal to the slave unit. The device detects reception, controls the output of the dial signal generation circuit, and only when communication is possible between the base unit and slave unit, generates a dial tone every time a key button is operated, and dials. To provide a radio telephone that immediately informs a user that a signal is being received by a base unit each time a key button is operated. (E) Embodiments The radio telephone of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a base unit connected to a telephone line L, and includes a transmitting section 2 and a receiving section 3. Reference numeral 4 denotes a portable handset, which has a receiving section 5 and a transmitting section 6 corresponding to the transmitting section 2 and receiving section 3, respectively. The receiving section 5 includes an antenna 7, a high frequency circuit 8 that amplifies the signal received by the antenna 7 and converts it into an intermediate frequency signal, an intermediate frequency amplification circuit 9 that amplifies the intermediate frequency signal, and a high frequency circuit 8 that amplifies the signal received by the antenna 7 and converts it into an intermediate frequency signal. It has a detection circuit 10 that converts the audio signal into a signal, an audio amplification circuit 11 that amplifies the audio signal, and a speaker 12. The transmitter 6 also includes a microphone 13, an audio amplification circuit 14 for amplifying the audio signal from the microphone 13, a modulation circuit 15 for FM modulating the audio signal, a high frequency amplification circuit 16 for amplifying the FM modulated signal, and an antenna 17. has. The transmitter 6 further includes a dial signal generating circuit 18 that generates a dial signal with a number of pulses corresponding to the number, a keyboard 19 that controls the dial signal generating circuit 18, and a dial tone that is generated each time a key button of the keyboard 19 is operated. It includes a dial tone generating circuit 20 that generates a signal, and a switch circuit 21. The switch circuit 21 is controlled by a DC signal obtained by rectifying a part of the intermediate frequency signal from the intermediate frequency amplification circuit 9 of the receiving section 5 in a rectifier circuit 22, and converts the dial tone generated by the dial tone generating circuit 20. The dial tone signal is applied to the audio amplification circuit 11 by passing the signal therethrough. Next, the operation of the wireless telephone of the present invention will be explained. When the power switch (not shown) of the handset 4 is turned on and the handset is put into operation, the modulation circuit 15 generates a carrier wave signal f ₁ and the high frequency circuit 16 After being amplified, it is radiated from the antenna 17. When the radiated carrier wave signal f ₁ is received by the base unit 1, a transistor is turned on, etc., and the transmitter 2 of the base unit 1 is then activated to generate the carrier wave signal f ₂ . When the carrier wave signal f ₂ is received by the receiving unit 5 of the handset 4, the base unit 1 and the handset 4 become communicable. According to the present invention, the carrier wave signal f ₂ received by the antenna 7 is amplified by the high frequency circuit 8 and converted into an intermediate frequency signal. Then, the intermediate frequency signal is amplified by the intermediate frequency amplification circuit 9, and a part thereof is taken out and rectified by the rectifier circuit 22 to obtain a DC voltage. The DC voltage is applied to the switch circuit 21, and the switch circuit 2
Turn on 1. When a key button on the keyboard 19 is operated in this state, a dial signal is generated from the dial pulse generation circuit 18 and applied to the modulation circuit 15. The dial signal is subjected to FM modulation of a carrier signal by a modulation circuit 15. The FM-modulated carrier wave signal is amplified by a high-frequency amplification circuit 16, then radiated from an antenna 17, and received by the receiving section 3 of the base unit 1. There, it is converted into a dial signal, and the telephone line L
The signal is then transmitted to the other party via , and the line is closed. When the key button is operated at the same time, the dial tone generating circuit 20 generates a dial tone signal. As mentioned above, since the switch circuit 21 is on at this time, the dial tone signal is transmitted to the audio amplifier circuit 1.
1 is amplified and the speaker 12 is sounded. Therefore, the operator can confirm that the dial signal is reliably received by base unit 1. On the other hand, since the handset 4 is far away from the base unit 1, the carrier wave signal f ₁ from the handset 4 is not received by the base unit 1, or conversely, the carrier wave signal f ₂ from the base unit 1 is received by the handset 4. When not, the intermediate frequency amplification circuit 9 of the handset 4 does not generate an intermediate frequency signal, so the switch circuit 21 remains off.
Therefore, even if a key button of the keyboard 19 is pressed, no dial tone is generated from the speaker 12, so that the operator knows that the dial signal is not being received by the base unit 1. In the above-mentioned embodiment, if the carrier signal _f2 from the base unit 1 is received by the slave unit 4, a part of the intermediate frequency signal is detected, and the DC voltage obtained by rectifying it is used to generate the dial tone generation circuit. The switch circuit 21 connected to the output side of 20 is turned on to generate a dial tone, but instead of detecting a part of the intermediate frequency signal,
FIG. 2 shows a system in which the FM noise signal generated when the carrier signal _f2 is not received by the handset 4 from the detection circuit 10 is used to activate and deactivate the dial tone generating circuit 20. . That is, when the carrier signal from the base unit 1 is not received from the detection circuit 10 of the receiving unit 5 of the slave unit 4, an FM noise signal is generated. This FM noise signal is detected by the filter 23 and the noise detection circuit 24, and the transistor 26 is turned on with the DC voltage rectified by the rectifier circuit 25. Then, the control signal applied to the dial tone generating circuit 20 becomes low level, and the dial tone generating circuit 20 is inactivated, so that the keyboard 19 is not activated.
Even if the key button is pressed, no dial tone is generated, informing the operator that a telephone call cannot be made. Next, as mentioned above, communication becomes possible between base unit 1 and slave unit 4, and carrier wave signal from base unit 1 is sent to slave unit 4.
When f ₂ is received, the FM noise signal disappears,
When the transistor 26 is turned off, the dial sound generation circuit 20 is activated, so when a key button on the keyboard 19 is pressed, a dial sound is generated from the speaker, indicating that the dial signal is being received by the base unit 1. Inform. (f) Effects As described above, the wireless telephone of the present invention detects when the base unit and the slave unit are in a state where they can communicate and a carrier wave signal from the base unit is received by the slave unit. Since the dial sound generation circuit is activated, when the key buttons of the keyboard are operated at this time, a dial sound signal is generated along with the dial signal, so it can be confirmed that the dial signal is received by the base unit. On the other hand, when the base unit and the slave unit are not ready for communication, no dial tone is generated even when a key button is pressed, so it is immediately obvious that a telephone call cannot be made.

[Brief explanation of drawings]

FIGS. 1 and 2 are circuit diagrams of a wireless telephone according to the present invention. 1...Base unit, 4...Slave unit, 5 ...Receiving section, 6 ...
...Transmission unit, 9...Intermediate frequency amplification circuit, 10...Detection circuit, 15...Modulation circuit, 18...Dial signal generation circuit, 19...Keyboard, 20...Dial sound generation circuit.

Claims (1)

[Claims] 1 Carrier wave signal f ₁ from the handset connected to the telephone line
and a transmitting unit that oscillates another carrier signal f ₂ when the carrier signal f ₁ is received by the receiving unit; It consists of a slave device having a corresponding transmitting section and a receiving section, and a modulation circuit that oscillates the carrier wave signal _f1 to the base device in the transmitting state in the transmitting section of the slave device, and a dial signal in response to keyboard operation. a dial signal generating circuit that generates a dial tone signal, a dial tone generating circuit that generates a dial tone signal for each operation of the keyboard, and a switch circuit that turns on and off the dial tone signal, so that the dial tone signal is received by the receiver of the handset. a high frequency circuit that converts the carrier wave signal _f2 into an intermediate frequency signal; an intermediate frequency amplification circuit that amplifies the intermediate frequency signal; a rectifier circuit that rectifies a part of the signal extracted from the intermediate frequency signal and applies it to the switch circuit; Additionally, an audio amplification circuit is provided to amplify the dial tone signal supplied via the switch circuit and drive a speaker, and by putting the slave unit into a transmitting state, it oscillates a carrier wave signal f ₁ and transmits it to the base unit, By receiving carrier wave signal f ₁ , carrier wave signal f ₂ was generated from the base unit, and the signal generated from the intermediate frequency amplification circuit of the slave unit that received the carrier wave signal f ₂ was rectified by a rectifier circuit. A radio telephone characterized in that a switch circuit is turned on by a signal, and a dial tone signal generated from a dial tone generating circuit generated by operating a keyboard is applied to an audio amplifier circuit to drive a speaker.