JPH0326702Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a telephone that has a built-in electronic circuit and is configured to extract driving voltage from a telephone line.

(b) Conventional technology In recent telephones, for example,
As shown in Japanese Patent No. 128760, a dialing circuit and the like are integrated into an IC, and a drive voltage is extracted from a telephone line and supplied to the IC.

In Japanese Utility Model Application Publication No. 56-128760, dial pulses are transmitted by switching transistors based on the output signal from the dial transmitting IC, but the dial pulse is transmitted at a location where the telephone is installed, that is, close to the switchboard. Since the line current fluctuates depending on the location, etc., there is a problem that the voltage value of the dial pulse signal generated by the switching of the transistor fluctuates, making it unstable and potentially causing malfunction.

(c) Problems to be Solved by the Invention The present invention has been made to solve the above-mentioned problems, and provides a telephone that stabilizes dial pulse transmission.

(d) Means for solving the problems The present invention is constructed so that a Zener diode, which stabilizes the voltage supplied to the electronic circuit, is used when transmitting dial pulses.

(E) Effect Since the present invention is constructed as described above, when switching the transistor that generates the dial pulse, the switching current flows through the Zener diode, thereby making it possible to stabilize the dial pulse voltage.

(f) Examples Embodiments of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a bridge rectifier circuit connected to telephone lines L ₁ and L ₂ , which is configured to extract driving voltage from the telephone lines L ₁ and L ₂ . An audio signal is superimposed on a DC voltage at the output of the rectifier circuit 1, and is supplied to a speech network circuit 3 via a transistor 2, and then connected to a handset 4 and a telephone line L via the speech network circuit 3. ₁ and _L2 are configured to transmit and receive audio signals.
5 is a control circuit that generates a dial pulse signal based on the telephone number data entered from the keyboard 6 consisting of a numeric keypad.It has a built-in memory, stores multiple telephone number data, and automatically dials with a simple operation. It is possible to automatically generate a dial pulse signal So corresponding to the selected telephone number. 7 is a dial pulse signal from control circuit 5
A transistor that is switched based on So,
The dial pulse is generated by controlling the conduction of a transistor 9 connected in series with a Zener diode 8 between power supplies. Reference numeral 10 denotes a transistor which is controlled to be non-conductive by the muting signal _S1 from the control circuit 5 during the period when the dial pulse signal So is being generated. acts to separate the telephone line from the telephone line.

Reference numeral 11 denotes a speaker receiver circuit that takes out an audio signal via a transformer 12, and the extracted audio signal is sent to an amplifier 14 via a variable resistor 13 for volume adjustment.
It is configured to be supplied to the computer and amplified by the speaker 15. A voltage stabilized by a Zener diode 8 connected to the primary side of the transformer 12 is supplied to the amplifier 14 via a speaker receiver switch 16. The speaker receiver button 17 is connected to the handset 4 by a mechanism not shown, and even if the speaker receiver button 17 is operated and locked, the lock is released and the device returns by picking up the handset 4.

Next, the operation of the present invention having such a configuration will be explained.

First, the operation of dialing and making a call will be explained. First, after picking up the handset 4 and closing the switch 18 and connecting the telephone lines L ₁ and L ₂ , when the telephone number of the other party is inputted from the keyboard 6, the control circuit 5 outputs a pulse signal So corresponding to the inputted telephone number. is generated, and the transistor 7,
9 is controlled by switching, a short circuit between the power supply terminals causes the dial pulse signal to be sent to the telephone line L ₁ ,
Sent to L ₂ . At this time, as shown in FIG. 2, the dial pulse signal is stabilized to a constant voltage of, for example, 4V by a Zener diode 8 during a short circuit. While the dial pulse signal is being sent, the output signal _S1 of the control circuit 5 is at a low level, the transistors 2 and 10 are non-conductive, and the speech network circuit 3, speaker receiving circuit 11 , etc. are connected to the telephone line _L1 , Separated from L ₂ . However, when the transmission of the dial pulse signal ends, the output signal _S1 of the control circuit 5 is inverted to a high level, so that the transistors 2 and 10 become conductive and the speech network circuit 3
Power is supplied to the unit and it becomes operational. Therefore, if the other party answers the dial call, the handset 4
You can make a call using this. At this time, the speech network circuit 3 includes a Zener diode 8.
A stabilized voltage is supplied to ensure stable operation.

Next, the speaker receiving operation for making a dial call while the handset 4 is left in place will be explained. To perform the speaker reception operation, first operate the speaker reception button 17 to close the switches 16, 16', and then perform the dialing operation in the same manner as described above. When the other party responds to the dial call, the voice signal of the other party is extracted by a transformer 12, inputted to an amplifier 14, and amplified by a speaker 15 by connecting a telephone line, so that the response of the other party can be confirmed. So I set handset 4 to make a call.
When the user picks up the phone, the speaker receiver button 17 is unlocked and the switch 18 is closed, allowing the handset 4 to make a call in the same manner as described above.

(g) Effects of the invention As mentioned above, the telephone of the invention connects a Zener diode, which stabilizes the driving voltage supplied to electronic circuits such as a speaker network circuit, to the dial pulse transmitting circuit when dial pulse signals are sent, and adjusts the dial pulse voltage. By stabilizing the drive voltage and dial pulse with a single Zener diode, the circuit configuration becomes simple and contributes to cost reduction.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing the configuration of a telephone according to the present invention, and FIG. 2 is an output waveform diagram of the main part of FIG. 1. 1... Rectifier circuit, 3... Speech network circuit, 4... Handset, 5... Control circuit, 8
... Zener diode, 11 ... Speaker receiver circuit.

Claims (1)

[Scope of utility model registration request] a bridge rectifier circuit connected to a telephone line; a first switching transistor having an emitter-collector connected to one output terminal of the circuit; and a first switching transistor connected between the output of the transistor and the other output of the rectifier circuit. a Zener diode, an electronic circuit such as a speech network to which a driving voltage is supplied from the diode, and a second switch having an emitter-collector connected between one output terminal of the rectifier circuit and a cathode electrode of the Zener diode. a switching transistor, and a control means for appropriately controlling switching of the first and second switching transistors, and the first transistor is configured to be non-conductive during a period in which a dial pulse is generated by switching of the second transistor. A phone featuring: