JPS58161452A - Telephone set circuit - Google Patents

Abstract

PURPOSE:To simplify the construction of a push button switch, by replacing mechanical common contacts of the push button switch by the 1st, the 2nd and the 3rd switching elements, and obtaining an oscillation signal without chattering. CONSTITUTION:When the push button is depressed, a frequency contact 31 is activated, the information is detected at an oscillation circuit 32, an oscillation signal is outputted via a resistor 33, a depression signal is outputted from a control output terminal 34 and fed to a control input terminal 60 of a switch control circuit 6. A signal turning off an NPN TR8 is outputted from the 2nd output terminal 62 of the circuit 6 to disconnect a channel circuit 5 from a line terminal 2. Simultaneously, a signal turning on a PNP TR7 is outputted from the 1st output terminal 61 of the circuit 6, both end terminals of the channel circuit 5 is short-circuited and an oscillation signal from a resistor 33 is fed to the line terminal 1. A signal turning on a PNP TR9 is outputted from the 3rd output terminal 63 of the circuit 6 and a resistor 10 is connected in parallel with a resistor 4.

Description

[Detailed Description of the Invention] 1. The present invention relates to a telephone circuit, especially a ZJlQ wave synthesis signal system.
This article concerns one circuit of a push-button dial telephone. Conventionally, this type of telephone circuit had a system in which the dial oscillation circuit and the telephone call circuit were switched using a mechanical contact of the push-button dial, as shown in Figure 1. was hiring. That is, in Fig. 1, 1 and 2 are the first and j120 line terminals, respectively, 3 is a dial oscillation circuit, and there is a common point 30 that operates in common to all push buttons, and a common point 30 that operates in common to all push buttons. It includes a frequency contact 31 that operates (makes), an oscillation circuit 32, and an output resistor 33, 4 is a bias resistor to the dial oscillation circuit 3, and 5 is a communication circuit. In Fig. 1, when all the push buttons are not pressed, the communication circuit 5 is connected to the line terminals 1 and 2 by the common contact 30, and the oscillation circuit 32 is disconnected from the line terminal 1. When the button is pressed, the common contact 30 is operated, the communication circuit 5 is disconnected from the line terminal l, the oscillation circuit 32 is connected to the line terminals 1 and 2, and the frequency contact 31 corresponding to the pressed button is connected. operates, and the oscillation circuit 32 oscillates a corresponding frequency, which is output via the output resistor 33 between the line terminals 1 and 2.

In the telephone circuit configured in this manner, the mechanical contact 30 is used to switch between the dial oscillation circuit 3 and the telephone call circuit 5, and due to the chattering phenomenon of the mechanical contact during switching, the number of dial signals is reduced. m5ec
The shortcoming is that the signal is interrupted and the effective signal time is shortened.

Furthermore, the pushbutton switch included in the dial oscillation circuit 3 is a rounded type having both a common contact 30 and a frequency contact 310, and its mechanism is complicated and expensive.The present invention solves these two drawbacks, 4. To provide a telephone circuit that sends out high-quality dial signals without chattering using a simple push button switch.According to the present invention, the first and 20th line terminals, the dial oscillation circuit, the IIl and second resistors a communication circuit, a switch control circuit, and first, second, and third switching elements, the first line terminal is connected to one end of the first resistor and the first switching element. one end of and the third
0 switching element 15111 and one end of the positive power supply terminal of the communication circuit, and the other end of the switching element of the Jll is connected to the negative power supply terminal of the communication circuit and one end of the second switching element. , the second line terminal is connected to the dial oscillation go negative power supply terminal and the other end of the second switching element O, and the other end of the j13 switching element is connected to the dial oscillation go through the second resistor. The positive power supply terminal of the circuit is connected to the other end of the first resistor O, the control output terminal of the dial oscillation circuit is connected to the input terminal of the switch control circuit, and the first
The output terminal of the switch control circuit is connected to the control input terminal of the first switching element, the second output terminal of the switch control circuit is connected to the control input terminal of the twentieth switching element, and the third output terminal of the switch control circuit is connected to the control input terminal of the twentieth switching element. A telephone circuit is obtained, which is characterized in that it is connected to the control input terminals of the third switching elements, respectively.

Next, one embodiment of the present invention will be described with reference to the drawings. Figure 2 is a block circuit diagram of one embodiment of the present invention.
are the first and @201i1 path terminals, 3 is the dial oscillation circuit, 4 is the resistor for III bias to the dial oscillation circuit 3, 5 is the communication circuit, 6 is the switch control circuit 1hb,
Furthermore, the dial oscillation circuit 3 includes a frequency contact 31 that operates (makes) in response to each push button, an oscillation circuit 32, and an output resistor 33.

Then, the first line terminal 1 is connected to one end of the first resistor 4 and the PNP as a first switching element. 1fIIAK connection of the positive power supply terminal of the circuit 5, and the collector of the above-mentioned PNP) Langistav is connected to the negative power supply terminal of the communication circuit 5 and the NP
N) Connect to the collector of the transistor 8, and connect the line terminal 2 of the N2 to the negative power terminal of the dial oscillation circuit 3 and the N2
The collector of the PNP transistor 9 is connected to the positive power supply terminal of the dial oscillation circuit 3 and the other end of the tenth resistor 4 via the second resistor 10. The dial oscillation circuit 30 control output terminal 34 is connected to the input terminal 6 of the switch control j16.
0, the first output terminal 61 of the switch control circuit 6 is connected to the PNP transistor 70 base, the second output terminal 62 of the switch control circuit 6 is connected to the NPN transistor 80 base, and the switch control circuit 3rd of 6
The output terminals 63 of the transistors are respectively connected to the bases of the PNP transistors.

When the pushbutton is not pressed, the frequency contact 31 is inactive, and this is detected by the oscillation circuit 32,
No oscillation output is sent to the resistor 33, and a signal indicating one press is output to the control output terminal 34, and this output is transmitted to the control input terminal 60 of the switch control circuit 60, and the first output terminal of the switch control circuit 6 61 to PNP) A signal is output to turn off the Langistaph, and the switch control w1
The second output terminal 62 of the switch control circuit 6 outputs a signal that turns on the NPN transistor 8, and the 30th output terminal 63 of the switch control circuit 6 outputs a signal that turns off the PNP transistor 9. Therefore, by turning on the NPN transistor 8, the communication circuit is connected to the line terminals 1 and 2. At this time, the oscillation circuit 320 operates so that no oscillation output is produced. Further, the oscillation circuit 32 is biased only by the resistor 4.

When the push button is pressed, the frequency contact 31 operates,
The information is detected by the oscillation circuit 32, and an oscillation signal is outputted via the resistor 33. At the same time, a press signal is outputted from the control output terminal 34, and transmitted to the control input terminal 60 of the switch control circuit 6, and the switch A signal for turning off the NPN transistor 8 is output from the second output terminal 62 of the control circuit 6, and the communication circuit 5 is disconnected from the line terminal 2. At the same time, PNP from the first output terminal 61 of the switch control circuit 6)
A signal to turn on the Ranjistaf is output, and both ends of the communication circuit 50 are short-circuited, and the oscillation signal from the resistor 33 is connected to the line terminal IK. Furthermore, the 30th output terminal 6 of the switch control circuit 6
3 to PNP) outputs a signal that turns on resistor 9 and connects resistor 10 in parallel to resistor 4.

By connecting this resistor 10 in parallel with the resistor 4, the circuit current of the oscillation circuit 32O increases significantly during oscillation compared to when there is no oscillation, so the bias resistance value that supplies the current necessary for its operation is reduced. I come because I have to. The tb oscillation circuit 32 uses the minimum necessary circuit current (usually 10
0 μm or less), but when the operation of the frequency contact 31 is detected,
It oscillates to send an oscillation signal between line terminals 1 and 2, but
In order to send out the oscillation signal without distortion, a circuit voltage tlt (usually several mA or more) is required, which is several orders of magnitude higher than the current required during non-oscillation, so the bias resistance should be a large resistor during non-oscillation. It is necessary to reduce the load on the communication circuit 5 and to reduce the bias resistance value so that undistorted oscillation output is sent between the line terminals 1 and 2 during oscillation ◎Resistor 4 is usually 10
41 or more, the resistor 9 is selected to be several hundred ohms.

As explained above, the present invention provides a mechanical common contact point of a pushbutton switch as a first contact point. By replacing the switching elements with the second and third switching elements, it is possible to obtain an oscillation signal without chattering, and there is an economical effect that the structure of the switch can be simplified.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block circuit diagram showing an example of a conventional circuit, and FIG. 2 is a block circuit diagram showing an embodiment of the present invention. 1...Line terminal, 2...Line terminal, 3
...Dial oscillation circuit, 4...Resistor, 5.Old telephone call circuit, 6...Switch control circuit, 7...PNP) Rungis/ , 8-・-NP
N) transistor, 9...NPN transistor,
IO・Old...Resistor, 3O・Old...Common contact, 31...
... Frequency contact, 32... Group oscillation circuit, 33...
...Resistor, 34, old...Control output terminal, 6o...
Mountain/control input terminal, 61...Group/control output terminal, 62...
・Group・Control 1tB power terminal, 63・Old・Control output terminal.

Claims (1)

[Claims] First and second line terminals, a dial oscillation circuit, and a first
and a second resistor, a communication circuit, a switch control circuit, and a first. and a second and third switching element,
connecting the first line terminal to one end of the first resistor and the other end of the first switching element to a negative power terminal of the communication circuit and one end of the second switching element; The second line terminal is connected to the negative power terminal of the dial output circuit and the other end of the second switching element, and the other end of the third switching element is connected through the second resistor. The positive power supply terminal of the dial oscillation circuit is connected to the other end of the first resistor, the control output terminal of the dial oscillation circuit is connected to the input terminal of the switch control circuit, and the first an output terminal of the gl switching element, a second output terminal of the switch control circuit as a control input terminal of the second switching element, and a third output terminal of the switch control circuit as the control input terminal of the second switching element.
A telephone circuit characterized in that the output terminals of the 113 switching elements are connected to the control input terminals of the 113 switching elements.