JPH0323732Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention uses the line current flowing through the signal line connected to the exchange in the telephone office to control the line connection of the signal line during emergency calls. The present invention relates to an emergency call control device for a telephone set.

[Prior art] Some public telephones do not require an external power source.
There are devices that operate various control circuits and coin storage mechanisms by using line current flowing through signal lines connected to the telephone office. Furthermore, some of the above telephones allow you to make an emergency call, for example to the police station or fire department, by pressing down on the emergency call switch on the front of the case, without having to insert a coin or magnetic card. There are some that have the ability to make calls.

An emergency call control device for such a telephone is configured as shown in FIG. 2, for example. That is,
In the figure, 1a and 1b are signal lines connected at one end to the telephone office, and the other ends of the signal lines 1a and 1b are connected to a handset (not shown) via capacitors 2a and 2b for blocking the direct current component caused by the line current. A communication circuit 3 is connected to the communication circuit 3 for transmitting a reception signal and inputting a transmission signal. On one of the signal lines 1a, a contact 4a of a switch that is linked to the operation of picking up the handset, and a contact 6a of a relay 6 driven by a control circuit 5 composed of a microprocessor or the like are inserted. Furthermore, signal line 1
a is connected to the A0 terminal of a rectifier circuit 8 that rectifies the line current via a chiyoke coil 7, and the A1 terminal of the rectifier circuit 8 is connected to the other contact 6b of the relay 6.
and is connected to the DC input terminal of the communication circuit 3 via the choke coil 9. Further, a smoothing capacitor 22 is inserted between the normally open terminal of the contact 6b and the other signal line 1b, and the normally closed terminal of the contact 6b is connected to the signal line 1b via a resistor 10 and a Zener diode. 11 and capacitor 12
It is connected to the B1 terminal of the rectifier circuit 8 via a parallel circuit with. B0 terminal of rectifier circuit 8 is signal line 1
connected to b. Both terminals of the capacitor 12 are connected to voltage input terminals VC and G of the control circuit 5.

The normally closed terminal of contact 6a of relay 6 is diode 1
3. It is connected to the signal line 1b via a self-holding relay 14 and an emergency call switch 15.
The cathode terminal of diode 13 is diode 16
and the contact 6b via the contact 14a of the relay 14.
connected to the common terminal of Also, the normally closed terminal of contact 4a of the switch is connected to contact 1 of relay 14.
4b and a diode 17 to the normally closed terminal of the emergency call switch 15.

In addition, the anode terminal of the diode 16 and the contact point 6
A coin contact 18a is connected to the common terminal b and is closed when a coin is inserted into the coin storage mechanism 18.
is inserted.

Further, the common terminal of the contact 6b is connected to the diode 21, the chiyoke coil 19, and the contact 6 of the relay 6.
c. Grounded via contact 4b of the switch.

The control circuit 5 also includes a contact 4 of a hook switch.
c, the opening/closing information of the contact 14c of the relay 14, the amount information from the coin storage mechanism 18, etc. are input.

In such an emergency call control device, when the handset is left in place, the contacts of the emergency call switch 15, the hook switch, and the contacts of the relays 6, 14 are in the open state or in the normally closed terminal side as shown in the figure. Since the input terminals 20a and 20b are connected, the input terminals 20a and 20b are completely disconnected from the communication circuit 3.

When the handset is picked up and the emergency call switch 15 is pressed, the contact 4a and the emergency call switch 15 are connected to the normally open terminal side. Therefore, the line currents of the signal lines 1a and 1b flow through the relay 14, so that it operates and the contacts 14a to 14c of the relay 14 are closed. Note that once this relay 14 is activated, it activates the emergency call switch 15.
It is self-retained even if it is released. Then, the input terminal 20a, contacts 4a, 6a, diodes 13, 1
6. A current supply path is formed by the contacts 14a and 6b, the resistor 10, the Zener diode 11, the B1 terminal and B0 terminal of the rectifier circuit 8, and the input terminal 20b.
As a result, capacitor 12 is charged with line current. Then, when the voltage between the terminals of the capacitor 12 rises to a specified voltage determined by the Zener voltage of the Zener diode 11, the control circuit 5 starts operating. Then, the control circuit 5 confirms that the emergency call switch 15 is turned on from the closed state of the contact 14c, and drives the relay 6. Then, each contact 6a, 6b is connected to the normally open terminal side. As a result, the input terminal 20a, contacts 4a, 6a, Chiyoke coil 7, A0 terminal of rectifier circuit 8, A1 terminal, contact 6b, Chiyoke coil 9, communication circuit 3, Zener diode 11, B1 terminal, B0 terminal of rectifier circuit 8, input A current supply path consisting of the terminal 20b is formed. Therefore, the capacitor 12 is constantly charged to a specified voltage by the line current.

When the call is over and the handset is put down, the control circuit 5 detects the open state of the switch contact 4c and returns the relay 6 to its original state. Therefore, each contact 6a, 6b, 6c of the relay 6 returns to its original state. On the other hand, when contact 4a of the switch is connected to the normally open terminal side, input terminal 20a and contact 4
a, 14b, diode 17, emergency call switch 15, relay 14, diode 16, contact 14
a, 6b, resistor 10, Zener diode 11,
B1 terminal, B0 terminal, input terminal 20b of rectifier circuit 8
A current circuit is formed. Therefore, a current in the opposite direction flows through the relay 14, so that the relay 14 returns to its original state and the contacts 14a, 14
b, 14c are open. As a result, the emergency call control device returns to its initial state.

[Problems to be Solved by the Invention] However, the emergency call control device configured as described above also has the following problems. In other words, since the minimum line current flowing through the signal lines 1a and 1b is about 20 mA, the relay 1 operates when the emergency call switch 15 is pressed.
4 requires very high sensitivity.

In addition, this relay body 14 and each contact 14a, 1
The volume of the entire relay including 4b and 14c is large compared to other electronic components, which not only increases the size of the entire device but also increases manufacturing costs. Also, each contact 1
The use of a large number of mechanical contacts including 4a, 14b, and 14c causes problems such as decreased durability and increased probability of failure due to contact life.

The present invention was developed based on these circumstances, and its purpose is to supply line current from the signal line to the charging circuit through the thyristor that responds to the operation of the emergency call switch, thereby reducing the power consumption of the circuit. An object of the present invention is to provide an emergency call control device for a telephone that has a simple configuration and can improve durability and reliability.

[Means for Solving the Problems] The emergency call control device for a telephone according to the present invention uses a line current flowing through a signal line connecting a telephone office and a telephone circuit that inputs a transmit signal to a handset and sends a receive signal. A charging circuit is provided to charge the
An auxiliary current supply path is provided in parallel with the current supply path from the signal line to the charging circuit, and a switching circuit that switches and connects the signal line to the communication circuit side or the auxiliary current supply path side, and a thyristor and a light emitting device are installed in the auxiliary current supply path. A thyristor gate circuit is installed in which the element is inserted and the line current flowing from the signal line is guided to the gate terminal of the thyristor in response to the switch operation of the emergency call switch, and is driven by the charging voltage of the charging circuit and receives the light emitted from the light emitting element. A control circuit is provided to control switching of the switching circuit to the communication circuit side.

[Function] With the emergency call control device for a telephone configured as described above, when the emergency call switch is pressed, the line current flowing from the signal line flows into the gate terminal of the thyristor via the gate circuit. Therefore, the thyristor becomes conductive and the charging circuit is charged. Then, the control circuit operates with the charging voltage of this charging circuit. Further, when the thyristor becomes conductive, the light emitting element emits light, the state of light emission is detected by the control circuit, and the signal line is switched and connected to the communication circuit side.

[Example] An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing an emergency call control device for a telephone according to an embodiment. That is, a pair of signal lines 21
One end of a, 21b is connected to the telephone office via each input terminal 22a, 22b, and the other end is connected to the capacitor 23.
It is connected to the communication circuit 24 via a and 23b. One signal line 21a has a switch contact 25a that is linked to the operation of picking up the handset.
Contact 2 of relay 27 driven by control circuit 26
7a is inserted. Further, the signal line 21a is connected to A0 of the rectifier circuit 29 via the chiyoke coil 28.
The A1 terminal of the rectifier circuit 29 is connected to the DC input terminal of the communication circuit 24 via the other contact 27b of the relay 27 and the choke coil 30. Note that a smoothing capacitor 31 is inserted between the normally open terminal of the contact 27b and the signal line 21b.

The normally closed terminal of contact 27b of relay 27 is resistor 32
B1 of the rectifier circuit 29 via a charging circuit consisting of a parallel circuit of a Zener diode 33 and a capacitor 34.
connected to the terminal. B0 of this rectifier circuit 29
The terminal is connected to the signal line 21b. Both terminals of the charging circuit consisting of the Zener diode 33 and the capacitor 34 are connected to the voltage input terminal VC of the control circuit 26,
connected to G.

Contact 2 of relay 27 inserted in signal line 21a
The normally closed terminal 7a is a diode 35, a thyristor 36 with the illustrated polarity, a resistor 37, and a light emitting diode 38a as a light emitting element forming one of the photocouplers.
It is connected to the common terminal of the contact 27b of the relay 27 via. However, this diode 35,
Thyristor 36, resistor 37, light emitting diode 38
a constitutes an auxiliary current supply path to the charging circuit. A thyristor gate circuit consisting of an emergency call switch 39, another contact 27c of the relay 27, and a resistor 40 is inserted between the anode terminal and gate terminal of the thyristor 36.
A resistor 41 is connected between the gate terminal and cathode terminal of 6. Furthermore, a Zener diode 42 of the polarity shown is connected between the cathode terminal of the thyristor 36 and the cathode terminal of the light emitting diode 38a, and a capacitor 43 and a capacitor 43 of the polarity shown are connected between the cathode terminal of the light emitting diode 38a and the gate terminal. A diode 44 is connected. Further, a diode 45 having the illustrated polarity is connected between the connection point between the capacitor 43 and the diode 44 and the cathode terminal of the thyristor 36.

Further, a coin contact 46a that closes when a coin is inserted into the coin storage mechanism 46 is inserted between the anode terminal of the thyristor 36 and the cathode terminal of the light emitting diode 38a.

Further, the anode terminal of the thyristor 36 is grounded via a diode 47 of the illustrated polarity, a chain coil 48, and a contact 25b of the switch.

The control circuit 26 becomes operational when a specified voltage is input between the voltage input terminals VC and G from a charging circuit consisting of a Zener diode 33 and a capacitor 34. Then, the opening/closing information of the switch contact 25c, the light emission information from the phototransistor 38b forming the other photocoupler, the amount information from the coin storage mechanism 46, etc. are input, and the relay 27 is driven and controlled based on these information. At the same time, a control signal is sent to the communication circuit 24.

The operation of the emergency call control device for a telephone configured as described above will be explained. First, when the handset is not picked up, the contacts 25a, 25b and 25c of the hook switch are in an open state as shown. In addition, each contact 27 of the relay 27
a and 27b are connected to normally closed terminals, and contact 2
7c is a closed state. Therefore, in this state, the line current input from the telephone office to the input terminals 22a, 22b is cut off by the contact 25a of the switch.

Next, when the emergency call switch 39 is pressed while the handset is picked up, the contact 25a and the emergency call switch 39 are closed. Therefore, input terminal 22a, contacts 25a, 27a, diode 35, emergency call switch 39, contact 27c, resistors 40, 41, 37, light emitting diode 38a, contact 27b, resistor 32, Zener diode 33, B1 of rectifier circuit 29. Terminal, B0 terminal, input terminal 22b
A current circuit is formed. Therefore, the diode 35, the emergency call switch 39, and the contact 27
c. A line current flows into the gate terminal of the thyristor 36 via the thyristor gate circuit consisting of the resistor 40. Therefore, this thyristor 36 becomes conductive.

When the thyristor 36 becomes conductive, the input terminal 22
a, contact 25a, contact 27a, diode 35,
Thyristor 36, resistor 37, light emitting diode 38
a, the contact 27b, the resistor 32, the Zener diode 33, the B1 terminal and B0 terminal of the rectifier circuit 29, and the input terminal 22b form a current supply path. Also, ground terminal E, contact 25b, and chiyoke coil 4
8, diode 47, thyristor 36, resistor 3
7. Light emitting diode 38a, contact 27b, resistor 3
2. Zener diode 33, rectifier circuit 29
A ground sending circuit consisting of the B1 terminal, the B0 terminal, and the input terminal 22b is formed.

Therefore, the charging circuit consisting of the Zener diode 33 and the capacitor 34 starts charging. When the voltage between the terminals of the capacitor 34 rises to a specified voltage determined by the Zener voltage of the Zener diode 33, the control circuit 26 starts operating. The control circuit 26 also includes a phototransistor 38b.
When the light emitting state of the light emitting diode 38a is confirmed from the conduction state of the light emitting diode 38a, the relay 27 is driven.

When the relay 27 is driven, each contact 27a, 2
7b is connected to the normally open terminal side and the contact 27
c is released. Therefore, this time, the input terminal 22a, the contacts 25a, 27a, and the chiyoke coil 2
8. A0 terminal, A1 terminal, contact 27 of rectifier circuit 29
b, Chi York coil 30, communication circuit 24, Zener diode 33, B1 terminal of rectifier circuit 29, B0
An outgoing call line consisting of the terminal and the input terminal 22b is formed. If an emergency call dialing operation is performed in this state, a dial pulse signal is sent out. Then, you can talk to the other party.

Note that since the thyristor 36 continues to operate at the time of forming the telephone circuit, the above-mentioned earth sending circuit includes the grounding terminal E, the contact 25b, the chiyoke coil 48, the diode 47, the thyristor 36, the resistor 37, the light emitting diode 38a, the contact 27b, The current paths are maintained by changing the current paths such as the CHI York coil 30, the communication circuit 24, the Zener diode 33, the B1 terminal and B0 terminal of the rectifier circuit 29, and the input terminal 22b.

Next, when the handset is put down, the contacts 25a, 25b, and 25c of the switch are opened, so the control circuit 26 confirms that the contact 25c is open and returns the relay 27 to its original state, and the communication circuit 24 to stop calling. Furthermore, since the contact 25a is opened, the inflow of line current is also stopped. The emergency call control device then returns to its original state.

In addition, when making a normal call other than an emergency call, when the handset is picked up and a coin is inserted into the coin slot, the coin storage mechanism 46 operates to close the coin contact 46a. Then, a current supply path passing through the coin contact 46a instead of the thyristor 36 is formed. Then, the charging circuit consisting of the Zener diode 33 and the capacitor 34 is charged in the same manner as described above.

When the handset is placed down and the contacts of the switch are opened, or when the coin storage mechanism sends out toll cut information, the control circuit 26 activates relay 2.
Return 7 to its original state.

In addition, Zener diode 42, capacitor 4
3. Resistor 37 and diode 44 are thyristor 36
This is an operation stabilization circuit for stabilizing the operation of the That is, when the thyristor 36 becomes conductive and a current supply path is formed between it and the telephone exchange,
When the line current is momentarily cut off due to noise or the like, the thyristor 36 is cut off, and the current supply path cannot be maintained thereafter. In order to avoid this, the capacitor 43 is charged with a constant voltage determined by the Zener voltage of the Zener diode 42, so that when the line current is interrupted and the thyristor 36 is cut off,
A gate current is supplied from the capacitor 43 to the gate terminal of the thyristor 36 via the diode 44. Then, when the line current returns, the thyristor 36 immediately returns to its original conductive state. Therefore, the current supply path can be maintained continuously even in the event of a momentary interruption of the line current.

In the emergency call control device for a telephone configured in this manner, the gate current of the thyristor 36 is controlled by operating the emergency call switch 39, and the line current is supplied to the charging circuit via the thyristor 36. ing. Therefore,
Unlike the conventional device shown in FIG. 2, it is not necessary to use a high-precision relay that operates directly on line current, so manufacturing costs can be reduced.

In addition, by using thyristors, it is possible to reduce the number of relays installed, which allows the entire device to be made smaller, and by reducing the number of mechanical contacts, it is possible to improve the durability and reliability of the device. .

Note that the present invention is not limited to the embodiments described above. In the embodiment, a ground sending circuit is provided, but it is possible to obtain substantially the same effects as in the above-described embodiment even with a device in which the ground sending circuit is removed.

[Effects of the invention] As explained above, according to the invention, line current is supplied from the signal line to the charging circuit that drives the control circuit via the thyristor that responds to the operation of the emergency call switch. Therefore, without using a high-precision relay, it is possible to have a simple configuration, reduce manufacturing costs, and improve durability and reliability.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an emergency call control device for a telephone according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional device. 21a, 21b...signal line, 22a, 22b...
...Input terminal, 24...Telephone circuit, 25a, 25
b, 25c... Hook switch contact, 26...
Control circuit, 27... Relay, 27a... Relay contact (switching circuit), 29... Rectifier circuit, 33...
Zener diode, 34...Capacitor, 36
...Thyristor, 38a...Light emitting diode (light emitting element), 38b...Phototransistor, 39
...Emergency call switch, 46...Coin storage mechanism.

Claims (1)

[Scope of utility model registration request] a charging circuit that is charged by a line current flowing through a signal line that connects a telephone office and a communication circuit that inputs a transmission signal to the handset and sends a reception signal; a current supply path from the signal line to the charging circuit; an auxiliary current supply path provided in parallel with the auxiliary current supply path; a switching circuit that switches and connects the signal line to the communication circuit side or the auxiliary current supply path side; a thyristor and a light emitting element inserted in the auxiliary current supply path; a thyristor gate circuit that responds to a switch operation of an emergency call switch and guides the line current flowing from the signal line to the gate terminal of the thyristor; and a thyristor gate circuit that is driven by the charging voltage of the charging circuit and receives light emitted from the light emitting element. An emergency call control device for a telephone, comprising: a control circuit that controls switching of the switching circuit to a call circuit side.