JPH08205216A - Key telephone system for housing single telephone set - Google Patents

Abstract

PURPOSE: To provide a key telephone system with which the line state of a single telephone set can be detected without generating a speaking loss. CONSTITUTION: Concerning the key telephone system for housing an individual telephone set which is provided with a base unit 2 connected to a trunk line 1 and an individual telephone set interface 3 for connecting the telephone set to the base unit 2 and can perform call origination and call termination by connecting the telephone set 5 through the telephone set interface 3 to the trunk line 1, in order to detect the line state of the telephone set 5, a line state detecting circuit 50 to turn a high impedance at the time of off-hook of the telephone set 5 is parallelly connected to the speech path of the telephone set interface 3 on the side of the telephone set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key telephone device which accommodates a single telephone.

[0002]

2. Description of the Related Art As a conventional button telephone device, for example,
As shown in FIG. 2, a main device 2 accommodating a plurality of office lines 1
In addition, it is known that a plurality of key telephones 4 are connected and a plurality of individual telephones 5 are connected via a single telephone interface unit 3. Here, a call line 6 and a data line 7 are provided between the main device 2 and each key telephone 4.
The individual telephone interface unit 3 and each individual telephone 5 are connected by a communication line 8.
The single telephone interface unit 3 may be provided outside the main device 2.

FIG. 3 shows a configuration of a main part of the key telephone device shown in FIG. The main unit 2 is the office line circuit 1
1, transformer 12, local line CPU 13, main CPU 1
4, a power supply device 15 and a single telephone interface unit 3, and the office line 1 includes an office line circuit 11 and a transformer 1.
It is connected to the single telephone interface unit 3 via 2.

Single telephone interface unit 3
Is a speech path switch 21, a transformer 22, a DC blocking capacitor 23, an impedance matching circuit 24, current supply circuits 25a and 25b, relay contacts 26a and 26b, a single telephone CPU 27, a resistor 28, a 16 Hz signal circuit 29, and a ring trip circuit 30. The communication path from the office line 1 includes a station line circuit 11, a transformer 12, and a communication path switch 2
1, the transformer 22, the DC blocking capacitor 23, the impedance matching circuit 24, the current supply circuits 25a and 25b, the relay contacts 26a and 26b, the ring trip circuit 30, and the call line 8 are connected to the single telephone 5. .

Here, the impedance matching circuit 24 is
It has a resistor 31, a constant voltage diode 32 and a diode 33 connected in series, and is connected in parallel between communication paths. In addition, the ring trip circuit 30 includes the photo coupler 3
4 is composed of a parallel circuit of a light emitting diode 34a and a resistor 35 of No. 4, a capacitor 36, and a varistor 37, and is connected in series to the communication path. In addition, the independent telephone 5 includes the hook switch 41 and the hook switch 4
A call circuit 42 selectively connected to the call line 8 by 1.
And a series circuit of the capacitor 43 and the receiving circuit 44.

Further, the + V output terminal of the power supply device 15 is 1
Connected to the 6 Hz signal circuit 29, the DC current output from the IR terminal of the 16 Hz signal circuit 29 is superimposed.
A Hz signal flows to the ground G via the relay contact 26a, the single telephone 5, the ring trip circuit 30, the relay contact 26b, and the resistor 28. The + V output terminal of the power supply device 15 is also connected to the current supply circuit 25a, and the current supply circuit 25a, the relay contact 26a,
Single telephone 5, ring trip circuit 30, relay contact 2
A direct current flows through the ground G through the 6b and the current supply circuit 25b. In addition, a single phone CP
U27 has a photo coupler 3 of the ring trip circuit 30.
4 is connected, and a relay circuit (not shown) for driving the relay contacts 26a and 26b is connected.

Local line CPU 13 and single telephone CPU 2
The main CPU 14 is controlled by the main CPU 14 according to software, the central line CPU 13 controls input / output of the central line circuit 11, and the single telephone CPU 27 controls input / output of the single telephone interface unit 3.

In the above structure, when the single telephone 5 is in the on-hook state, the DC current supplied from the power supply device 15 through the current supply circuit 15a is blocked by the capacitor 43 of the single telephone 5, and therefore the single telephone 5 has the same structure. Since the communication path has high impedance, photo coupler 3
The light emitting diode 34a of No. 4 does not light up, and the phototransistor 34b is turned off.

From this state, the individual telephone 5 is used for making a call.
When the hook is off-hook, the hook switch 41 causes the call circuit 4
Since the circuit connected to the second side has a low DC resistance, the light emitting diode 34a of the photocoupler 34 is connected to the current supply circuit 2
The light is turned on by the direct current from 5a, whereby the phototransistor 34b is turned on and its collector becomes the potential of the ground G. In this state, the single phone CPU2
7, the communication path switch 21 is activated based on the detection, and the main CPU 13 and the office line CPU 13
After that, the office line loop forming circuit 11a of the office line circuit 11 operates to form a communication path between the office line 1 and the individual telephone 5.

When an incoming call arrives at the independent telephone 5, the incoming call is detected by the station line CPU 13 via the station line circuit 11.
Based on that, the main CPU 14, the single telephone CPU2
7 and a relay contact 2 via a relay circuit (not shown)
6a and 26b perform a switching operation in the ringing cycle of the single telephone 5, and in synchronization with the switching operation, a 16 Hz signal on which the direct current from the 16 Hz signal circuit 29 is superimposed is supplied to the single telephone 5.

During this incoming operation, the relay contact 26
When a is connected to the IR terminal side of the 16 Hz signal circuit 29 and the relay contact 26b is connected to the resistor 28 side,
That is, when the single telephone 5 is off-hook while the 16 Hz signal in which the direct current from the 16 Hz signal circuit 29 is superimposed is supplied to the single telephone 5, the call circuit 42
Is connected to the communication line 8 and the circuit has low DC resistance,
The light emitting diode 34a of the photocoupler 34 has a frequency of 16 Hz.
Light is emitted in response to a signal from the signal circuit 29, which turns on the phototransistor 34b, and in the same manner as described above, the communication path switch 21 and the office line loop forming circuit 11a operate, and the office line 1 and the individual telephone 5 A call path with is formed.

Also, during the incoming call operation, when the relay contact 26a is connected to the current supply circuit 25a side and the relay contact 26b is connected to the current supply circuit 25b side, that is, the disconnection period of the signal of 16 Hz to the single telephone 5 When the single telephone 5 is hooked off, the photocoupler 34 is turned on by the direct current from the current supply circuit 25a, as in the case of the above-mentioned transmission.

When the single telephone 5 is on-hook due to the termination of the call due to the above-mentioned outgoing or incoming response, the call circuit 42 is opened and the circuit becomes high impedance, and the phototransistor 34b of the photocoupler 34 is turned off. This state is detected by the single-telephone CPU 27, and the communication path switch 21 is deactivated based on the detection, and the station line loop forming circuit 11a of the station line circuit 11 is deactivated via the main CPU 13 and the station line CPU 13, and the station The communication path between the line 1 and the single telephone 5 is opened.

[0014]

However, in the above-mentioned conventional button telephone device, the ring trip circuit 30 having the photocoupler 34 is connected in series to the single telephone communication path side of the single telephone interface unit 3. Since the photocoupler 34 is turned on while the individual telephone 5 is off hook, that is, the line state of the individual telephone 5 is detected during the call, there is a problem that a call loss occurs and the call quality deteriorates.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to appropriately detect the line state of a single telephone without causing a call loss and, therefore, without degrading the call quality. It is an object of the present invention to provide a key telephone device that accommodates a configured single telephone.

[0016]

In order to achieve the above object, the present invention comprises a main unit connected to a central office line and a single telephone interface for connecting a single telephone to the main unit. In a button telephone device accommodating a single telephone configured to connect a single telephone to the office line via the single telephone interface to perform an outgoing call and an incoming call, in order to detect the line state of the single telephone, It is characterized in that a line state detection circuit, which becomes high impedance when the single telephone is off-hook, is connected in parallel to the speech path on the single telephone side of the single telephone interface.

The line state detection circuit has a photocoupler, and is configured to detect the line state of the single telephone by turning the photocoupler on when the single telephone is on-hook and off when the single telephone is off-hook. And

The single telephone interface has an impedance matching circuit having a constant voltage diode connected in parallel to the speech path on the side of the single telephone, and the photo coupler is connected in series with the impedance matching circuit. And

The single telephone interface sends a 16 Hz call signal to the single telephone at 16 Hz.
A signal circuit is provided, and a resistor is connected in series to a loop for sending out the ringing signal from the 16 Hz signal circuit, and a call is caused by a voltage drop in the resistor due to the response of the single telephone during the sending out of the ringing signal. It is characterized in that the path voltage is set to be lower than the standard voltage value of the constant voltage diode, and the photocoupler is turned off at the time of response during transmission of the calling signal.

[0020]

In the present invention, since the line state detection circuit connected in parallel to the call path on the side of the single telephone of the single telephone interface becomes high impedance during the telephone call of the single telephone, almost no line state detection circuit is provided during the telephone call. No current flows. Therefore, call loss can be reduced,
It is possible to improve the call quality.

[0021]

FIG. 1 shows an embodiment of the present invention.
Components having the same functions as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the photocoupler 51 is connected in series with the impedance matching circuit 24.
The line state detection circuit 50 is connected, and this series circuit is connected to the ground G from the power supply device 15 via the current supply circuit 25a, the light emitting diode 51a of the photocoupler 51, the impedance matching circuit 24, the relay contact 26b and the current supply circuit 25b. Connect in parallel to the telephone line of a single telephone so that a direct current flows through. Further, the emitter of the phototransistor 51b constituting the photocoupler 51 is connected to the ground G, and the collector is connected to the single telephone CPU27 via the inverter 52.

In this configuration, when the single telephone 5 is in the on-hook state, the speech path on the individual telephone 5 side becomes high impedance, and the speech path voltage becomes higher than the voltage of the constant voltage diode 32 of the impedance matching circuit 24. A direct current flows from the power supply device 15 to the ground G via the current supply circuit 25a, the light emitting diode 51a of the photocoupler 51, the impedance matching circuit 24, the relay contact 26b, and the current supply circuit 25b, which causes the phototransistor 51b of the photocoupler 51 to operate. Turned on,
The output of the inverter 52 becomes high level.

When the single telephone 5 is off-hook to make a call, the telephone line on the side of the single telephone 5 has a low impedance, and the telephone line voltage becomes lower than the voltage of the constant voltage diode 32. No current flows through the light emitting diode 51a, so that the phototransistor 51b is turned off and the output of the inverter 52 becomes low level. That is, in this off-hook state, the photocoupler 51 is off and has a high impedance. Therefore, there is no call loss and the call quality can be improved.

Also, during the incoming operation to the individual telephone 5, the relay contact 26a is connected to the 16 Hz signal circuit 29 side and the relay contact 26b is connected to the resistor 28 side, respectively, and a direct current is superimposed on the individual telephone 5. During the period of supplying the signal of 16 Hz, the current supply circuit 2 is supplied from the power supply device 15.
5a, photocoupler 51, impedance matching circuit 2
4, a DC current flows through the relay contact 26b and the resistor 28 to the ground G, so that the photocoupler 51 is turned on.

When the individual telephone 5 is answered off-hook in this state, the speech path on the individual telephone 5 side becomes low impedance, and the potential at the connection point 53 between the impedance matching circuit 24 and the speech path is from the 16 Hz signal circuit 29. Since the signal of 16 Hz on which the DC current is superimposed rises due to the voltage drop by the resistor 28 and the communication path voltage becomes lower than the voltage of the constant voltage diode 32, the photocoupler 51 is turned off.

Also, during the incoming call operation, when the relay contact 26a is connected to the current supply circuit 25a side and the relay contact 26b is connected to the current supply circuit 25b side, that is, a disconnection period of a signal of 16 Hz to the single telephone 5 is set. When the individual telephone 5 is off-hook, the photocoupler 51 is turned off because the communication path on the side of the individual telephone 5 becomes low impedance as in the case of the above-mentioned outgoing call.

[0027]

According to the present invention, the line state detection circuit of the single telephone is connected in parallel to the speech path on the side of the single telephone of the single telephone interface, and the line state detection circuit becomes high impedance during off-hook of the single telephone. In this way, since the call current does not flow in the line state detection circuit, the call loss can be reduced and the call quality can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a main part of an embodiment of the present invention.

FIG. 2 is a diagram showing a system configuration of a key telephone device accommodating a single telephone.

FIG. 3 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 1 station line 2 main device 3 single telephone interface unit 4 button telephone 5 single telephone 8 speech line 11 station line circuit 12,22 transformer 13 station line CPU 14 main CPU 15 power supply device 21 speech path switch 23,43 capacitor 24 impedance matching circuit 25a, 25b Current supply circuit 26a, 26b Relay contact 27 Single telephone CPU 28, 31 Resistor 29 16Hz signal circuit 32 Constant voltage diode 33 Diode 41 Hook switch 42 Communication circuit 44 Reception circuit 50 Line state detection circuit 51 Photocoupler 51a Light emitting diode 51b Phototransistor 52 Inverter 53 Connection point

Claims (4)

[Claims] 1. A main unit connected to an office line, and a single telephone interface for connecting a single telephone to the main unit, wherein the single telephone is connected to the central line via the single telephone interface. In a button telephone device accommodating a single telephone capable of making an outgoing call and an incoming call by means of the single telephone, in order to detect the line state of the single telephone, the single telephone is provided in a call path on the single telephone side of the single telephone interface. A button telephone apparatus for accommodating a single telephone, characterized in that a line state detection circuit that becomes high impedance when off-hook is connected in parallel. 2. The line state detection circuit has a photocoupler, and is configured to detect the line state of the single telephone by turning the photocoupler on when the single telephone is on-hook and off when the single telephone is off-hook. A key telephone device for accommodating the single telephone according to claim 1. 3. The single telephone interface has an impedance matching circuit having a constant voltage diode coupled in parallel to a speech path on the single telephone side, and the photocoupler is connected in series with the impedance matching circuit. A key telephone device accommodating a single telephone according to claim 2. 4. The single telephone interface sends a 16 Hz ringing signal to the single telephone 16H.
a z-signal circuit, a resistor is connected in series to the ringing signal sending loop from the 16 Hz signal circuit, and a voltage drop in the resistor due to the response of the single telephone during sending the ringing signal, Make sure that the communication path voltage is lower than the standard voltage value of the constant voltage diode,
4. The key telephone apparatus for accommodating a single telephone according to claim 3, wherein the photo coupler is turned off at the time of response during transmission of the ringing signal.