JPH0537605A - Telephone set control section restoring circuit - Google Patents

Abstract

PURPOSE:To allow a telephone set to reply normally to an incoming call generated succeedingly even when the telephone set is left hooked-off and a power supply from an exchange to the telephone set is interrupted by detecting a non-voltage state at hook off and restoring the relay of a control circuit. CONSTITUTION:A non-voltage state of a telephone circuit 2 at hook-off is detected and the relay of a control circuit 40 of the telephone set is restored in a prescribed time after the non-voltage state is detected. A telephone set control section restoring circuit 6 supplies a current to make coils 43, 44 of a TS relay and an SS relay after lapse of a prescribed time (e.g. 2sec) after the no-voltage at hook off to bring contacts Ts, ss to the make state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone control section restoration circuit for performing a restoration operation of a telephone control circuit in accordance with a stop of DC power supply from a telephone exchange.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing an example of a circuit configuration used in a conventional telephone 3.

In this conventional example, a telephone set 3 is connected to an exchange 1 via a subscriber telephone line 2 and terminals L1 and L2. The incoming call ringing unit 10 and the incoming call monitoring relay 20 are AC-connected to the subscriber telephone line 2 via the capacitor C1 and the hook switch hs0, and the power supply unit 30 joins via the hook switch hs1, the diode D2, and the ss contact. It is connected to the telephone line 2. The diodes D1 and r
A series circuit composed of r1 contacts and ts contacts is connected in parallel with the diode D2.

Between the positive electrode 39 and the negative electrode 37 of the power supply unit 30, a capacitor C2 for stabilizing the load, a control circuit unit 40, a self-holding type TS relay and an SS relay are connected, and the communication circuit unit 50 is It is connected between the negative electrode 37 and the terminal L2.

The control circuit section 40 includes a break coil 48 for a TS relay and a break coil 49 for an SS relay.
And the make coil 43 of the TS relay and the make coil 44 of the SS relay are connected, and the other end of each relay coil (the terminal on the side opposite to the control circuit unit 40) is connected to the positive electrode 39 of the power supply unit 30. There is. The control input unit 47 of the control circuit unit 40 is connected to the negative electrode 37 via the hook switch hs2 and to the positive electrode 39 via the resistor R46.

Here, when the handset of the telephone 3 is hooked (hereinafter referred to as "on-hook"), the hook switches hs0 and hs1 are connected to the ON-side contacts, and the hook switch hs2 is in the make state. .. Also,
When the handset is lifted from the hook (hereinafter referred to as "off-hook"), the hook switches hs0 and hs1
Is connected to the OFF side contact, and the hook switch hs2 is in the break state. When a current flows from the terminal 23 to the terminal 24, the incoming call monitoring relay 20 puts the rr0 contact into a break state, the rr1 contact into a make state, and the relay 2
It is a latch type relay that maintains the state even after the current to 0 is stopped. When a current flows from the terminal 24 to the terminal 23, the rr0 contact maintains the make state, and rr1
The contact maintains the break state.

The TS relay has break coils 48, 4
This is a latch-type relay that makes the ts contact break when the current flows through it and makes the ts contact make when the current flows through the make coils 43 and 44. Note that ts
The contacts normally break during a DC loop during off-hook and make up during on-hook. The SS relay operates in the same manner as the TS relay, and the ss contact normally breaks during a DC loop during off-hook and makes up during on-hook. When the ts contact and the ss contact are in the make state, the TS relay and the SS relay are said to be in the restored state.

Next, the operation of the above conventional example will be described.

FIG. 3 shows the operation of each relay when the telephone 3 is in the incoming call state in the above conventional example.

When the telephone 3 is in the incoming call state, the terminal L
The DC power supply whose terminal L1 is + for 2 is supplied from the exchange 1, and the terminal L1--hook switch hs1--diode D2--power supply unit 30-negative electrode 37-communication circuit unit 50-terminal L2 DC circuit, the power supply unit 30, the call circuit unit 50 operates. The control circuit unit 40 is connected between the positive electrode 39 and the negative electrode 37 of the power supply unit 30, and the power supply unit 3
The output voltage of 0 operates and the capacitor C2 accumulates electric charges by the output voltage of the power supply unit 30. At this time, the control circuit unit 40 energizes the break coils 48 and 49 of the TS relay and the SS relay, and the ts contact and the ss contact are in the break state.

When the telephone 3 is on-hook in this state, the hook switch hs0 is switched to the ON-side contact,
Terminal L1--ON side contact of hook switch hs1--r
r0 contact --- diode D0 --- incoming call monitoring relay 20-
-A DC circuit of the terminal L2 is configured. With this DC circuit, the incoming call monitoring relay 20 has its terminals 23 to 2
4, the rr0 contact is brought into a break state (the state at this time is shown in FIG. 4), and the DC circuit of the telephone 3 is opened. Therefore, the output of the voltage from the power supply unit 30 is stopped, but the control circuit unit 40 continues to operate by the DC voltage charged in the capacitor C2.

By the above-mentioned on-hook, the hook switch hs2 is made, and the hook input terminal 4 of the control circuit section 40 is made.
7, the control circuit unit 40 controls the capacitor C2
To TS relay, SS relay make coil 43,
A current is passed through 44 to make the ts contact and the ss contact. The capacitor C2 is discharged by energizing each relay, and the operation of the control circuit unit 40 is stopped after this discharge.

[0013]

In the above-mentioned conventional example, in order to prevent invalid hold of the line when the telephone 3 is left in the off-hook state after the end of the call,
The exchange 1 stops the supply of DC power after a certain period of time. By stopping the supply of the DC power in this way, the operation of the power supply unit 30 is stopped, and eventually the capacitor C2
Is discharged, and the control circuit section 40 stops its operation while the ts contact and the ss contact of the self-holding type TS relay and SS relay remain in the break state. When the hook is turned on in this state, the supply of DC power from the exchange 1 is restarted.

After that, when an incoming call is received from the exchange 1, a DC power source whose terminal L2 is positive is supplied to the terminal L1. At this time, if it goes off-hook, the ts contact and the ss contact remain in the break state, so that there is a problem that direct current power does not flow from the terminal L2 to the terminal L1 and the incoming call cannot be answered.

Also, for example, when the subscriber telephone line 2 is accidentally disconnected temporarily during construction of the subscriber telephone line 2 and a telephone call is in progress at this time, the same phenomenon as described above occurs. There is a problem that occurs. That is, even if an incoming call is received after the subscriber telephone line 2 is properly connected, the incoming call cannot be answered.

According to the present invention, even if the telephone is left in an off-hook state and is on-hook after the power supply to the telephone from the exchange is cut off, the telephone control section can be normally responded to an incoming call thereafter. The purpose is to provide a circuit.

[0017]

DISCLOSURE OF THE INVENTION The present invention is to detect a non-voltage state of a telephone line during off-hook and restore a relay of a control circuit of a telephone after a predetermined time has passed since the non-voltage state was detected. ..

[0018]

FIG. 1 is a circuit diagram showing a state in which a telephone control unit restoration circuit 6 according to an embodiment of the present invention is included in a telephone 3a.

The telephone 3a is the same as the conventional telephone 3 except for the telephone control section restoration circuit 6.

The telephone control unit recovery circuit 6 makes the make coils 43 of the TS relay and the SS relay after a predetermined time (for example, 2 seconds) has passed since no voltage was applied during off-hook.
A current is passed through 44 to control the ts contact and the ss contact in the make state. That is, the telephone control unit restoration circuit 6 uses the + terminal 66 and − terminal 67 of the power source to supply the power source unit 3
Power is supplied from 0, an input signal is received from the OFF side terminal of the hook switch hs1 via the input terminal 65, and two seconds after the input signal becomes zero voltage, the TS control terminal 68 and the SS control terminal 69 Then, a current is passed through the make coils 43 and 44 of the TS relay and the SS relay to control the ts contact point and the ss contact point to the make state.

FIG. 2 is a circuit diagram specifically showing the telephone control unit restoration circuit 6 according to the above embodiment.

The telephone control section restoration circuit 6 has a no-voltage detection section 61, a timing circuit section 62, and a relay control section 63.

The no-voltage detector 61 monitors the no-voltage state of the subscriber telephone line 2 at the time of off-hook, and its input terminal 65 is connected to the OFF-side terminal of the hook switch hs1. In addition, the no-voltage detector 61 includes resistors R1 and R2 that divide the input signal input from the input terminal 65.
A diode D1, a transistor Q1 that is turned on / off according to the voltage of its input signal, a collector resistor R3 of this transistor Q1, and an inverter I1 that inverts the collector voltage of the transistor Q1. The output signal becomes the output signal of the no-voltage detector 61.

The timing circuit 62 is a circuit which outputs a control signal for controlling the TS relay and the SS relay two seconds after the detection of the non-voltage state of the telephone line 2, the transmission circuit and the two frequency dividers X1. , X2. The oscillation circuit has a crystal oscillator Xtal, inverters I2 and I3, and resistors R7 and R8. The frequency divider X1 has an input terminal CK1
And a reset input r1 and an output terminal q12, and the frequency divider X2 has an input terminal CK2, a reset input r2, and an output terminal q5.

The relay control unit 63 is an example of a relay control unit that restores the relay of the control circuit of the telephone after a predetermined time has passed after detecting the non-voltage state in the telephone line. It is a circuit that restores the TS relay and the SS relay of the control circuit unit 40 of the telephone 3a two seconds after the voltage state is detected. That is, the relay controller 6
3 is for making the ts contact and the ss contact of the TS relay and the SS relay, receiving the control input from the timing circuit 62 and sending the output to the make coils 43 and 44 of the TS relay and the SS relay. Is. Specifically, the relay controller 63 includes a transistor Q2 that drives the TS relay and a transistor Q that drives the SS relay.
3 and base resistors R9 and R10.

The positive terminal 66 of the power source is connected to the positive electrode 39 of the power source 30, and the negative terminal 67 of the power source is the negative electrode 3 of the power source 30.
Connected to 7. The TS control terminal 68 is connected to the make coil 43 of the TS relay, and the SS control terminal 69 is connected.
Is connected to the make coil 44 of the SS relay.

As the transistors Q1, Q2 and Q3, for example, a transistor 2SC1815 is used,
A crystal oscillator Xtal having a frequency of 32.768 kHz used for a clock is used, CMOS 4069UB is used as the inverters I1, I2 and I3, and a CMOS 4040 is used as the frequency dividers X1 and X2.
B is used.

Next, the operation of the above embodiment will be described.

First, in the above embodiment, when the telephone 3a is on-hook, the positive electrode 3 of the power supply unit 30 of the telephone 3a is used.
Since the DC current is not supplied from 9, the telephone control unit recovery circuit 6 has stopped its operation. After that, by going off-hook, the direct current circuit between the exchange 1 and the telephone 3a is closed, and the direct current power is supplied from the telephone 1, whereby the positive electrode 39 of the power supply unit 30 of the telephone 3a supplies power to the respective parts. The controller recovery circuit 6 starts operating.

When DC power is supplied to the telephone control section recovery circuit 6, a + voltage is generated at the input terminal 65 to turn on the transistor Q1. At this time, its collector is "L".
And the inverter I1 outputs "H". Since the reset inputs r1 and r2 of the frequency dividers X1 and X2 of the timing circuit unit 62 receive the output “H” of the inverter I1 and are in the reset state, the frequency division operation is not started and the output q12 thereof is output. , Q5 are “L”. Therefore, the transistors Q2 and Q3 of the relay control unit 63 are both off, no current flows through the make relays 42 and 43 of the TS relay and SS relay of the telephone 3a, and the contacts ts and ss are in the break state. Is.

Next, in the off-hook state, the exchange 1
The power supply from the power supply is stopped or the telephone 3
When a is accidentally disconnected from the subscriber telephone line 2, the voltage of the input terminal 65 becomes 0V, the transistor Q1 turns off, its collector outputs "H", and the output of the inverter I1 becomes "L". .. As a result, the timing circuit 6
The reset inputs r1 and r2 of the two frequency dividers X1 and X2 start the frequency dividing operation in order to input "L". Divider X
1 and X2 start operating to divide the frequency of the 32.768 kHz clock signal input to the clock input CK1 of the frequency divider X1, and after 2 seconds have elapsed from the start of operation of the timing circuit unit 62, the frequency divider "H" is output to the output q5 of X2. Then, the frequency divider X2 outputs "H", whereby the transistors Q2, Q of the relay control unit 63 are output.
3 turns on, a current flows through the make coils 43 and 44 of the TS relay and SS relay of the telephone 3a, the ts contact and the ss.
The contacts are in the make state. Therefore, even if the telephone is left in the off-hook state and is on-hook after the power supply from the exchange to the telephone is cut off, the ts contact and the ss contact are released 2 seconds after the DC voltage of the subscriber telephone line 2 becomes 0V. Since it is in the make state, it can normally respond to incoming calls that occur thereafter.

In the off-hook communication state, if a momentary interruption pulse from the exchange 1 or a momentary interruption of the subscriber line 2 occurs,
If the voltage at the OFF side terminal of the hook switch hs1 becomes 0V and the voltage recovers within 2 seconds, the transistor Q
Since the collector of 1 outputs “L” and the output of the inverter I1 becomes “H”, “H” is input to the reset inputs r1 and r2 of the frequency dividers X1 and X2 to stop the frequency division operation, Since the output continues to be in the “L” state, the relay control unit 36
Transistors Q2 and Q3 remain off, and the TS relay and SS relay make coil 4 of the telephone 3a.
No current flows through 3, 44, and the ts contact and the ss contact continue to be in the break state and the call can be maintained. In other words, a momentary interruption pulse from the exchange 1
Even if a momentary interruption of the subscriber line 2 occurs, the call is not adversely affected.

In the above embodiment, the timing circuit 62 outputs the control signal 2 seconds after detecting the non-voltage state of the telephone line 2. However, the control signal is output after a predetermined time other than 2 seconds. May be output.

[0034]

According to the present invention, even if the telephone is left in the off-hook state and is on-hook after the power supply from the exchange to the telephone is cut off, it is possible to normally respond to the incoming call thereafter. Has the effect.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a state in which a telephone control unit restoration circuit 6 according to an embodiment of the present invention is included in a telephone 3a.

FIG. 2 is a circuit diagram specifically showing a telephone control unit restoration circuit 6 according to the above embodiment.

FIG. 3 is a diagram showing an example of a circuit configuration used in a conventional telephone 3.

FIG. 4 is a diagram showing a state in which the telephone 3 is on-hook in the above conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Exchanger, 2 ... Subscribed telephone line, 3a ... Telephone, 6 ... Telephone control section restoration circuit, 61 ... No-voltage detection section, 62 ... Timing circuit, 63 ... Relay control section, 65 ... Input terminal, 66 ... Power supply + Terminals, 67 ... Power supply negative terminal, 10 ... Incoming call ringing section, 20 ... Incoming call monitoring relay, 30 ... Power supply section, 37 ... Negative electrode, 39 ... Positive electrode, 40 ... Control circuit, 47 ... Hook input terminal, 50 ... Call circuit section , Hs0, hs1, hs2 ... Hook switch, Q1, Q2, Q3 ... Transistor, I1, I2, I3 ... Inverter, X1, X2 ... Divider, CK ... Clock input, r1, r2 ... Reset input.

Claims (1)

Claim: What is claimed is: 1. A recovery circuit of a relay for controlling a telephone call of a telephone; a non-voltage detection unit for detecting a non-voltage state of a telephone line when off-hook; A telephone control comprising: a timing circuit that outputs a signal after a predetermined time; and a relay control unit that restores the relay of the control circuit of the telephone after the predetermined time after detecting the non-voltage state. Department recovery circuit.