JPS58161457A - Telephone set circuit - Google Patents

Abstract

PURPOSE:To simplify the construction of a push button switch, by replacing mechanical contacts of the push button switch by the 1st and the 2nd switching element, 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 a PNP transistor(TR)7 is outputted from the 1st output terminal 61 of the circuit 6 to disconnect a channel circuit 5 from a line terminal 1. A signal turning on an NPN TR8 is outputted from the 2nd output terminal 62 of the circuit 6, an oscillation signal from a resistor 33 is fed to a line terminal 2 to connect a resistor 9 in parallel with a resistor 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a telephone circuit, and a telephone circuit for a 4IK two-frequency composite signal system push button dial telephone.

Conventionally, as shown in FIG. 1, this type of telephone circuit has adopted a system in which a mechanical contact of a push button dial is used to switch between a dial oscillation circuit and a speech circuit. That is, in FIG. 1, 1 and 2 are the first and second line terminals, respectively;
3 is a diamond oscillator circuit, which has a common contact 30 that operates in common to all push buttons, and a common contact 30 that operates in response to each push button (
It includes a frequency contact 31 for making (make), 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 separated from the line terminal 1.

When the push button is pressed, the common contact 30 is operated, the communication circuit 5 is disconnected from the line terminal 1, the oscillation circuit 32 is connected to the line terminals 1 and 2, and the frequency contact corresponding to the pressed button is activated. 31 operates, the oscillation circuit 32 oscillates the corresponding frequency, and the line terminal 1,
It is output between 2.

In the telephone circuit configured in this way, the mechanical contact 30 is used to switch between the dial oscillation circuit 3 and the telephone call circuit 5, so the dial signal is interrupted for several meters due to the chattering phenomenon of the mechanical contact during switching. This had the disadvantage that the effective signal time was shortened.

Further, since the push button switch included in the dial oscillation circuit 3 includes both a common contact 30 and a frequency contact 31, its mechanism is multi-wire and expensive.

The present invention solves the above-mentioned one and two drawbacks and provides a telephone-like circuit that sends out a high-quality dialing signal without chattering with an easy-to-use push-button switch.

According to the present invention, the device includes first and twentieth wire terminals, a dial oscillation circuit, first and second resistors, a communication circuit, a switch control circuit, and first and second switching elements. , the line terminal of the fIg1 is connected to the positive power supply terminal of the dial oscillation circuit and the line terminal of the first switching element III.
IK connection, the other end of the switching element of the tIg1 is connected to the positive power supply terminal of the communication circuit, and the 20 line terminal is connected to 1m of the first resistor, the negative power supply terminal of the communication circuit, and the second Connect to 111# of the switching element of
The other end of the second switching element O is connected to the negative power supply terminal of the dial oscillation circuit through the second resistor and the first
and connect the control output terminal of the dial oscillation circuit to the input terminal of the switch control circuit;
A first output terminal of the switch control circuit O is connected to a control input terminal of the first switching element, and a second output terminal of the switch control circuit O is connected to a control input terminal of the second switching element. A characteristic telephone circuit is obtained.

Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block circuit diagram of one embodiment of the present invention.

1.2 is the first and second line tide, 3 is the dial oscillation circuit, 4 is the resistor for the first bias to the dial oscillation circuit 3, 5 is the closing circuit 5.6 is the switch control circuit .

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. the positive power supply terminal of the first switching element and the PN of the first switching element.
P) Connect to the emitter of the Langistaffe, PNP) Connect the collector of the Langistav to the positive power supply terminal of the talking circuit 5, and connect the second line terminal 2 to one end of the first resistor 4 and the talking circuit. 5 is connected to the emitter of the NPN) transistor 8 as the second switching element, and the collector of the NPN) transistor 8 is connected to the second switching element.
is connected to the negative power supply terminal of the dial oscillation circuit 3 and the other end of the first resistor 4 via a resistor 9, and the control output terminal 34 of the dial oscillation circuit 3 is connected to the input terminal of the switch control circuit 6. 60, the first output terminal 61 of the switch control circuit 6 is connected to the base of the PNP transistor 7, and the second output terminal 62 of the switch control circuit 6 is connected to the base of the NPN transistor 80. .

When the push button is not pressed, the frequency contact 31 is not operating, and this is detected by the oscillation circuit 32, and it is desired to send an oscillation output to the resistor 33, and a signal indicating that it is not pressed is output to the control output terminal 34. This output signal is transmitted to the control input terminal 60 of the switch control circuit 6, and a signal for turning on the PNP transistor 7 is output from the first output terminal 61 of the switch control circuit 6 as output '7', the first output terminal 61 of the switch control circuit 6. A signal that turns off the NPN transistor 8 is output from the output terminal 62 of the transistor 2. Therefore, the PNP transistor 7 is turned on (K) and the communication circuit is connected to the line terminals 1 and 2. Also, the oscillation output of the oscillation circuit 32 is NPN)
The oscillation circuit 32 is isolated from the line terminal 2 by the resistor 8, and 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 output via the resistor 33, and a press signal is output from the control output terminal 34, which is transmitted to the control input terminal 60 of the switch control circuit 6 to control the switch. A signal for turning off the PNP transistor 7 is output from the first output terminal 61 of the circuit 6, and the communication circuit 5 is disconnected from the line terminal 1. Further, the second output terminal 62 of the switch control circuit 6 outputs a signal that turns on the NPN transistor 8, connects the oscillation signal from the resistor 33 to the line terminal 2, and connects the oscillation signal from the resistor 33 to the line terminal 2.
is connected in parallel to resistor 4.

Connecting the resistor 9 in parallel with the resistor 4 means that the circuit current of the oscillation circuit 32 increases significantly during oscillation compared to when it does not oscillate, so the bias resistance value that supplies the current necessary for its operation is increased. This is because it needs to be made smaller. The oscillation circuit 32 has a minimum circuit current (usually 100μ
When the operation of the frequency contact 31 is detected, it oscillates to send an oscillation signal between the line terminals 1 and 2. To send data without distortion, a circuit current several orders of magnitude higher than that required when no oscillation is required (usually several mA or more) is required, so when no oscillation is required, the bias resistor should be a large resistor to reduce the load on the communication circuit 5. However, during oscillation, it is necessary to reduce the bias resistance value so that a distortion-free oscillation output is sent between the line terminals 1.degree. Usually, the resistor 4 is selected to be IOKΩ or more, and the resistor 9 is selected to be several thousand.

As explained above, the present invention makes it possible to obtain an oscillation signal without chattering and to simplify the structure of the switch by replacing the mechanical common contact of the push button switch with the first and second switching elements. There is an economic effect.

[Brief explanation of the drawing]

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
...Guillard oscillation circuit, 4...Resistor, 5...Telephone circuit, 6...Switch control circuit, 7...PNP) Langista, 8...
...NPN) transistor, 9...Resistor, 3
0... Common contact, 31... Frequency contact, 32... Oscillation circuit, 33... Resistor, 6o... Control input terminal , 61... Control output terminal, 62... Control output terminal. 277- Leather l concave 2 figure

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 second switching element, and the first line terminal is connected to the positive power terminal of the front P dial oscillation circuit and the first The other end of the first switching element is connected to the positive power supply terminal of the communication circuit, and the second line terminal is connected to one end of the first resistor and the communication circuit. A negative power supply terminal is connected to the IM of the second switching element, and the other end of the second switching element is connected to the negative power supply terminal of the dial oscillation circuit and the first resistor via the second resistor. the control output terminal of the dial oscillation circuit is connected to the input terminal of the switch control circuit;
A telephone circuit, wherein an output terminal of the switch control circuit is connected to a control input terminal of the first switching element, and a second output terminal of the switch control circuit is connected to a control input terminal of the second switching element.