JPS60105352A - Telephone-set circuit - Google Patents

Abstract

PURPOSE:To reduce the price of a telephone-set circuit by transmitting a dial- pulse oscillation output to a line by disconnecting a calling circuit directly, and by limiting the transistor to one in which a DC large current passes. CONSTITUTION:The pulse which is equivalent to the button input is transmitted from the oscillation output terminal of a dial-pulse oscillation circuit 3 at the time of dialing, a transistor 22 is connected or disconnected by the signal, and the dial signal is transmitted to the line by disconnecting the DC loop of a calling circuit 4 directly. At this time, the control output terminal voltage of the dial-pulse oscillation circuit 3 becomes earth electric potential, and a transistor 23 turns off. Then, a transistor 24 operates, and a power-supply condenser 26 of a receiving amplifier is short-circuited. Thus, a receiving amplifier 6 is brought into the nonoperational condition, and it is prevented that the dial click sound generates in the receiver.

Description

[Detailed description of the invention] The present invention relates to telephone circuits.

Conventionally, in this type of telephone circuit, as shown in FIG. 1, one transistor is connected in series with the telephone circuit, and the circuit is switched between when talking and when dialing. In addition, for the output of the dial pulse, another transistor was connected to the output of the dial pulse oscillation circuit to connect and disconnect the DC loop. That is, in FIG. 1, l and 2 are the first
．． gzO line terminal, 3 is dial pulse oscillation circuit, 11
is a dial pulse output transistor, 12 is a resistor, 1
3 is a dial pulse control output transistor; %14 is a transistor controlled by the operation of the transistor 13; and 4 is a communication circuit.

During a call, a signal for operating the transistor 13 is output from the control output terminal of the dial pulse oscillation circuit 30, thereby operating the transistor 14. At this time transistor 11
doesn't work. Conversely, during dialing, a signal to turn off the transistor 13 is output from the control output terminal of the dial pulse oscillation circuit 30, thereby turning off the transistor 14 as well.

Further, an output signal is output from the output terminal of the dial pulse oscillation circuit 3, and the transistor 11 operates.

Since such a circuit requires two transistors through which a large DC current from the switching equipment flows, a transistor with a large capacity and withstand voltage is required9, resulting in an increase in cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a telephone circuit which eliminates the above-mentioned drawbacks by directly outputting a dial pulse oscillation output intermittently to a telephone call circuit without using a circuit separate from the telephone call circuit.

The present invention connects the first line terminal, the positive power supply terminal of the dial pulse oscillation circuit, and the terminal of the PNP l-transistor of iEl, and connects the base of the first oPNP) transistor and the collector of the first NPN) transistor. Then, connect the base of the NPN) transistor of the it to the output terminal of the dial pulse oscillation circuit, and connect the control output terminal of the dial pulse oscillation circuit to the base of the second ONPN) transistor.

Connect the collector of the first PNP transistor, one end of the resistor, the collector of the third NPN transistor, one end of the capacitor, one end of the receiver, the positive power terminal of the receiver amplifier, and one end of the communication circuit excluding the receiver circuit. and the other end of the resistor and the collector of the second NPN transistor and the third
The emitter of the third NPN transistor, the other end of the capacitor, the negative power terminal of the receiver amplifier and one end of the constant current circuit are connected, and the receiver The other end is connected to the output terminal of the reception amplifier, and the second line terminal, the negative power supply terminal of the dial pulse oscillation circuit, the emitter of the first NPN transistor, the emitter of the second ONPN transistor, and the It is constructed by connecting the other end of the current circuit and the other end of the communication circuit excluding the receiving circuit.

Next, a non-inventive embodiment will be described with reference to the drawings.

FIG. 2 is a block diagram showing a part of an embodiment of the present invention, in which 1 and 2 are first and second line terminals, respectively, and 3 is a dial pulse oscillation circuit.

21 is the first NPN transistor which is the output transistor of the dial pulse oscillation circuit 3; 22 is the [l] PNP transistor controlled by the operation of the transistor 11; 23 is the dial pulse oscillation circuit 30 control output transistor 2; 24 is a third ONPN) transistor controlled by the operation of the transistor 23, 25 is a resistor that biases the transistor 24, 5 is a receiver, 6 is a receiver amplifier, 7 is a foot current circuit ,
26 is a power supply capacitor for the receiver amplifier, and 4 is a communication circuit excluding the receiver circuit.

and the II/LIOm path terminal l, the positive power supply terminal of the dial pulse oscillation circuit 3, and the emitter t? of the PNP transistor 22 of Ml? Connect the first PNP) run raster 220 base and the first NPN) transistor 21 collector, and connect the 15g1 NPN) u:, tji: x,
The base of p2x and the output terminal of the dial pulse oscillation circuit 3 are connected, the control output terminal of the dial pulse oscillation circuit 3 and the base of the second NPN transistor 230 are connected, and the collector of the first PNP transistor 22 and the resistor are connected. One end of the receiver 25, one end of the capacitor 26, one end of the handset 5, and the positive power terminal of the two-channel amplifier 6, and the communication circuit 4 excluding the receiver circuit.
one end connected to the other end of the resistor 25, the emitter of the third ONPN transistor 24, the other end of the capacitor 26, and the negative power supply terminal of the receiver amplifier 6;
One end of the foot current circuit 7 is connected to t, the other end of the receiver 5 is connected to the output terminal of the receiver amplifier 6, and the line terminal 2 of m2 and the negative power terminal of the dial pulse oscillation circuit 3 are connected to the other end of the receiver 5 and the output terminal of the receiver amplifier 6 are connected. 1st NPN) emitter of transistor 21 and 2nd front l1
The other end of the ei current circuit 7 is connected to the other end of the talking circuit 4 excluding the receiving circuit.

During a call, the oscillation output terminal voltage of the dial pulse oscillator circuit 3 is connected to the positive power supply potential of the oscillation circuit, so the transistors 21 and 22 are operating and the DC communication loop is closed. Further, since the control output terminal voltage of the dial pulse oscillation circuit 30 is also at the positive power supply potential, the transistor 23 is operated and the transistor 24 is turned off.

During dialing, a pulse equivalent to a button input is sent out from the oscillation output terminal of the dial pulse oscillation circuit 30, and the signal causes the transistor 22 to be disconnected and connected to connect and disconnect the DC loop of the direct communication circuit, thereby sending a dial signal to the line. At this time, the control output terminal voltage of the dial pulse oscillation circuit 30 becomes the ground potential, the transistor 23 is turned off, the transistor 24 is activated, and the power supply capacitor 26 of the receiver amplifier is short-circuited. As a result, the receiver amplifier 6 is kept in an inoperable state, thereby preventing dial click sounds from being generated on the handset.

By configuring the circuit in this way, the number of transistors through which a large direct current flows can be reduced to t-1, and although the number of transistors is one more than the conventional circuit, the capacity of the transistor used in the control circuit is The pressure resistance is small and the overall cost can be reduced.

Furthermore, the DC loop is interrupted and interrupted through the communication circuit, but if the circuit is of a capacitive type, there will be no effect on the make rate or the like. Normally, the communication circuit is completely electronic.
c circuit is used.

As explained above, the present invention has a dial pulse oscillation output t.
By discontinuing the i-connection circuit and transmitting it to the line, there is an effect of reducing the cost of the telephone circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional telephone circuit. FIG. 2 is a block diagram showing an embodiment of the present invention. 1, 2...Line terminal, 3...Dial pulse oscillation circuit, 4...Telephone circuit, 5...
...Telephone receiver. 6... Receiving amplifier, 7... Foot current circuit, 11... Dial pulse oscillation output transistor, 12... Resistor, 13... ...Dial I (control transistor of the Luss oscillation circuit, 14...
...transistor controlled by transistor 13,
21...-y' ear ts, a pulse oscillation output transistor, 22... a transistor controlled by the transistor 21, 23... a control output transistor of a tire pulse oscillation circuit, 24...
...transistor controlled by transistor 23,
25...Resistor, 26...Reception amplifier/1 power supply capacitor. Half 1 @ Rod 2 times

Claims (1)

[Claims] Connect the first line terminal, the positive power supply terminal of the dial pulse oscillation circuit, and the emitter of the 1l OPNP transistor, and connect the base of the PNP l-transistor of the i1 and the NPN of the il
) connecting the collector of the NPN transistor, connecting the base of the N1 NPN transistor to the output terminal of the dial pulse oscillation circuit, and connecting the control output terminal of the dial pulse oscillation circuit to the base of the second NPN transistor; (1) connecting the collector of the transistor, one end of the resistor, the collector of the third ONPN transistor, one end of the capacitor, one end of the receiver, the positive power terminal of the receiver amplifier, and one end of the channel circuit excluding the receiver circuit; the other end of the resistor, the collector of the second NPN transistor, and the third
Connect the base of the ONPN transistor and connect the third O
NPN) The emitter of the transistor, the other end of the capacitor, the negative power terminal of the receiver amplifier and one end of a constant current circuit are connected, the other end of the receiver is connected to the output terminal of the receiver amplifier, and 2 line terminal, the negative power supply terminal of the dial pulse oscillation circuit, the emitter of the first NPN transistor, the emitter of the second NPN transistor, the other end of the constant current circuit, and the telephone circuit other than the receiver circuit. A telephone circuit characterized in that the other ends are connected.