JPH021438B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a call switching system in which a call path switch is provided in a central unit of an automatic branch exchange, a key telephone, etc., and the call path switch is remotely controlled from a terminal. The present invention relates to a telephone device in which a manual switch is provided on the terminal to enable telephone calls.

Conventionally, in order to transfer central office lines in the event of a power outage, private branch exchange equipment is equipped with a battery to hold a minimum number of calls.The battery is used to hold calls using the power supply, and a battery is installed in series with the central office line to detect the end of a call. Configurations such as inserting a communication current monitoring relay or inserting a relay that monitors the voltage between one of the station lines and the ground are used. However, this configuration requires a large-capacity battery, deteriorates call quality, and has drawbacks such as the need to connect the device to the ground.

In addition to the above-mentioned configuration that automatically switches, there are also systems that are equipped with a manual switch to enable switching calls by manual operation during a power outage or power supply. However, this method was inconvenient because switching was sometimes forgotten.

In order to eliminate the drawbacks of both of the above two methods, the present invention provides a cable that bypasses calls to the central office line during a power outage, and further provides a manual changeover switch in the telephone set, so that when a power outage occurs, the switch can be operated to switch between central office lines and telephone calls. To provide a telephone device in which the switch is connected to the telephone communication circuit through the side path during a power outage to enable a telephone call, and the switch has an automatic recovery structure when the power is turned on, thereby eliminating the inconvenience caused by forgetting to switch the switch. be.

The present invention will be explained in detail below using the drawings.

FIG. 1 shows an embodiment of the present invention, in which 2 is a relay, 2-1, 2-2 are contacts of the relay 2, 4-7,
9 and 10 are diodes, 8 is a channel switch matrix, 14 is a manually operated changeover switch, 14
-1 to 14-3 are contacts of the switch 14, 15 is a telephone communication circuit, 16 and 22 are transistors, 17
is the plunger winding, 18 and 23 are fixed resistors,
24 is a relay, 24-1 is its contact, 100 is a main device (ME), 200 is a button telephone (KT), 2
0 is a communication line, and 21 is a pair of wires used for power supply. Further, the figure only shows a portion of the key telephone device relating to switching calls during a power outage, and other portions are omitted here because they are not directly related to the present invention and can be realized by known means.

Next, the operation of the illustrated embodiment will be explained. Now, when the power is turned on, the telephone communication circuit 15 is turned on by the switch 14.
By manually switching to the solid line side, contact 14-
1, 14-2, the communication line 20 is connected to the central office line via the communication line switch matrix 8, and communication is possible. Here, [power supply → fixed resistor 23
→ Contact 24-1 → Between base and emitter of transistor 22 → Ground] Direct current flows through the route,
The collector and emitter of the transistor 22 are turned on, and a direct current flows through the relay 2 via the route [power supply → relay 2 → collector and emitter of the transistor 22 → ground] to operate it, and its contact 2-1 , 2-2 are in the state of dotted lines, and power is supplied from the main device 100 to the key telephone 200 using the paired wire 21. Here, even if the switch 14 is operated and the contact becomes a dotted line state when the power is turned on, the telephone communication circuit 15 is disconnected from the office line at the contacts 2-1 and 2-2, and the power supply is connected through the diode 10. It is cut off and no current flows.

Next, since the power is cut off during a power outage, relay 2 is restored. Here, the diodes 4 to 7 constitute a rectifier circuit for always obtaining an output with a constant polarity even when the polarity of the central line changes. Also, switch 1
When you press 4 and switch to the dotted line side, if the polarity of the office line is (+) on the upper side as shown in the figure, then the telephone circuit 1
5 is [station line (upper side) → diode 4 → relay 2
4 → solid line of contact 2-1 → one side of pair 21 → diode 10 → dotted line of switch 14-2 → communication circuit 1
5 → Dotted line of switch 14-1 → Other side of paired line 21 →
Solid line of contact 2-2 → diode 7 → central line (lower side)]
It is connected to the central office line via this route, making it possible to make calls.
Here, the diode 9 prevents the DC power from flowing into the circuit of the plunger 17.

As explained above, switching is made by changing the polarity of the DC voltage between when electricity is on and when there is a power outage, making it possible to transmit two types of information using a pair of cables: when electricity is on and when there is a power outage.

Next, a description will be given of the recovery operation of the switch 14 when the switch 14 is pressed to make a call during a power outage, the switch 14 is left as it is, and the switch 14 is turned on. An embodiment showing the mechanical structure of the switch 14 is shown in FIG. In FIG. 2, 33 and 34 constitute plungers, 34 is a fixed part, and 33 is a movable part. 3
0 to 32 constitute a lock type push button switch,
30 is a switch body, 31 is a key top, and 32 is a recovery protrusion. In the circuit of FIG. 2, when the key top 31 is pushed in the direction of arrow _A1 , the main body 30
The contacts 14-1 to 14-3 mounted on the switch switch to the dotted line side and remain locked. Next, when the movable part 33 of the plunger moves in the direction of arrow _A2 , the protrusion 32 is pushed and the key top 31 moves in the direction opposite to arrow _A1 , and the switch is restored.

The details of the structure of this plunger are generally widely used and are well known, and will therefore be omitted here.

Next, the operation of the movable part of the plunger will be explained using FIG. Now, if a call is made during a power outage and the power is energized, direct current from the office line flows through the relay 24 through the route described above, activating it, and contact 2
4-1 is on the dotted line side, and since the base current of the transistor 22 is cut off, the relay 2 does not operate even if it is energized. Therefore, the conversation in the above state is maintained. Next, when the call is ended and the handset is turned on, the call current is cut off, the direct current flowing through the relay 24 is cut off, and the relay 24 is restored. As a result, contact 2
The base current of the transistor 22 flows through the transistor 22 through the transistor 4-1, turning on the collector-emitter thereof, causing current to flow through the relay 2 to operate it, and switching the contacts 2-1 and 2-2 to the dotted line side. Here, since the contact 14-3 is in the state shown by the dotted line, the base current of the transistor 16 is [power supply → dotted line side of the contact 2-2 → upper side of the pair 21 → fixed resistor 16 → contact 14
-3 dotted line side → between base and emitter of transistor 16 → diode 9 → lower side of pair 21 → contact 2
-1 dotted line side → ground], and turns on between the collector and emitter of the transistor 16. Therefore, the plunger 17 has the power supply → the dotted line side of the contact 2-2 → the upper side of the pair 21 → the plunger 17 → the collector-emitter of the transistor 16 → the diode 9 → the lower side of the pair 21 → the contact 2-1. A current flows along the route from the dotted line side to the ground, and pushes out the movable part 33 of the plunger 17. As a result, the switch 14 is restored, its contact 14-3 is switched to the solid line side, and the current in the plunger 17 is also cut off.

FIG. 3 shows a modification of the part within the dotted line in FIG. 1, in which the instantaneous current flowing to the plunger 17 is supplied from the capacitor 26, and the instantaneous large current flowing to the pair wire 21 when the plunger 17 is operated can be reduced. Here, 25 is a pulse signal generator, and resistor 27
The driving pulse is generated at a time interval longer than the time constant of the capacitor 26.

As can be understood from the above description, the telephone device of the present invention is configured such that the main device 1 maintains the connected state only when the power is turned on, and releases the connected state when the power goes out.
In a telephone device configured such that a telephone line 20 of a telephone 200 is connected to a central office line via a telephone line switch 8 provided at a pair of cables 21, and a power-on side contact and a power-off side contact for connecting the telephone communication circuit of the telephone to the telephone side of the telephone line when the power is on, and to the telephone side of the pair of cables during the power outage, respectively, by manual switching. a manual changeover switch 14 having a manual changeover switch 14, which monitors a loop current flowing through the pair of cables when a telephone communication circuit of the telephone is connected to the telephone side of the pair of cables by the manual changeover, and determines whether the loop current is at a predetermined value; a loop current monitoring circuit 24 that outputs an output when the voltage exceeds the voltage, a DC power source having an output terminal that outputs a required DC output voltage when the current is applied, and a loop current monitoring circuit 24 that outputs a DC output voltage when the current exceeds the voltage. Connected full-wave rectifier circuits 4, 5,
6, 7, and the main unit sides of the pair of cables are connected between the output terminals of the DC power supply, or a voltage of opposite polarity to the DC output voltage of the DC power supply is connected from the central line to the rectifier circuit. Cable switching circuits 2-1 and 2-2 connected to the output side of the full-wave rectifier circuit and the main device side of the pair of cables are configured such that when the DC power supply is energized and the loop current The loop current monitoring circuit is connected between the output terminals of the DC power supply when there is no output from the monitoring circuit, and when the DC power supply is energized and there is an output from the loop current monitoring circuit, and when the DC power supply is out of power. a cable switching control circuit 2, 22, 23, 24-1 that controls the cable switching circuit so that the cable switching circuit is connected to the output circuit of the full-wave rectifier circuit even when there is no output; a plunger 147 connected to the telephone side of the cable, and when the power is turned on from the power outage, the plunger is actuated by the DC current flowing from the DC power supply through the pair of cables, and the output of the plunger is used to operate the plunger 147. A control mechanism 9, 16, 18, 14-3 configured such that a manual changeover switch is switched to the current-carrying side contact.
and arranged on the telephone side of the pair of cables so as to be in the forward direction with respect to a direct current flowing from the office line to the telephone communication circuit of the telephone via the full-wave rectifier circuit and the pair of cables during a power outage. It has a configuration including a diode 10.

As explained in detail above, the present invention is capable of using conventional batteries and line monitoring relays in telephone systems such as switchboards, pushbutton telephones, and line concentrators in which a call changeover switch is installed in a central device to perform switching operations. It makes it possible to switch telephones during power outages without any hassle, and also eliminates the disadvantages of conventional manual switches such as forgetting to turn them off. It has great practical effects, such as being inexpensive and eliminating the need for battery maintenance.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a schematic diagram showing a mechanical example of a plunger portion used in the present invention, and FIG. 3 is a circuit diagram showing a modification of a part of the circuit shown in FIG.

Claims (1)

[Scope of Claims] 1. The telephone line is connected to the central office line via a line switch provided in the main device so that the connected state is maintained only when the power is turned on and the connected state is released when the power goes out. In the telephone device configured as above, a pair of cables are provided between the main device and the telephone separately from the telephone line, and a telephone circuit of the telephone is connected to the telephone side of the telephone line when the electricity is energized, and a cable is connected to the telephone side of the telephone line during the power outage. a manual changeover switch having an energized side contact and a power outage side contact for connection to the telephone side of the pair of cables by manual switching; and a communication circuit of the telephone to the telephone side of the pair of cables by manual switching. a loop current monitoring circuit that monitors the loop current flowing through the pair of cables when the current is applied and outputs an output when the loop current exceeds a predetermined value; and an output terminal that outputs a required DC output voltage when the current is applied. a full-wave rectifier circuit connected between the office lines so as to extract a DC output voltage from the office line; and a main unit side of the pair of cables connected between the output terminals of the DC power supply. or a cable switching circuit connected to the output side of the full-wave rectifier circuit so that a voltage having a polarity opposite to the polarity of the DC output voltage of the DC power source is supplied from the office line via the rectifier circuit; The main device side of the cable is connected between the output terminals of the DC power supply when the DC power supply is energized and there is no output from the loop current monitoring circuit; Cable switching control that controls the cable switching circuit so that it is connected to the output circuit of the full-wave rectifier circuit even when there is an output and when there is no output from the loop current monitoring circuit at the time of the power outage of the DC power supply. a circuit, a plunger connected to the telephone side of the pair of cables when the power is energized, and the plunger is operated by a DC current flowing from the DC power source through the pair of cables when the power is switched from the power outage state to the power supply time. a control mechanism configured such that the manual changeover switch is switched to the energized contact by the output of the plunger; A telephone device comprising: a diode disposed on the telephone side of the pair of cables so as to be in a forward direction with respect to a direct current flowing through a communication circuit.