JP2889889B2 - Intercom equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a communication device for making a call between one master unit and one of a plurality of slave units, and in particular, to the state of the slave unit. The present invention relates to a device for displaying.

[Prior Art] As the above-mentioned communication device, for example, US Pat.
No. 744,103 as disclosed in the specification. In this communication device, the following three signals are sent from the slave unit to the master unit. The first is a call-in signal for calling the master unit from the slave unit, and the second is a request to preferentially talk to itself when a plurality of slave units are calling the master unit. Priority signal for the third
Is a privacy signal indicating that the call from the base unit has been rejected.

In order to generate these three types of signals, the configuration is as shown in FIG. In the figure, 2 is a slave unit, 4
Is an exchange, and the handset 2 and the exchange 4 have four lines D, E, T,
The slave unit 2 is connected by G and has two changeover switches 6 and 8. The switch 6 has a contact 6a.
6a is floating in the normal state, and is switched to the privacy contact 6b or the call contact 6c by operating. The switch 8 is a self-return type, and the contact 8a contacts the call side contact 8b in a normal state, and switches to the priority side contact 8c only during operation.

In the state shown in FIG. 7, the voltage of the line T is +12 V, but when the contact 6a of the switch 6 is switched to the call side contact 6c side, the line T, the contact 8a, the contact 8b, the contact 6
c, a current flows through the contact 6a and the line G, and the voltage of the line T becomes 0V. The voltage on this line T is passed through a multiplexer 8 to a comparator.
It is supplied to 10, but since it has changed from + 12V to 0V,
Comparator 10 generates a call-in signal. In the state shown in FIG. 7, the contact 8a of the switch 8 is connected to the priority side contact.
When switching to the 8c side, a voltage V (+12>V> 0) obtained by dividing +12 V by the resistors R1 and R2 is generated on the line T, and is supplied to the comparator 10 via the multiplexer 8, and the comparator 10 Generate a signal. When the contact 6a of the switch 6 is switched to the privacy contact 6b from the state shown in FIG. 7, the intermediate tap of the primary winding of the transformer 12 of the speaker is grounded, and the intermediate tap of the primary winding of the transformer 12 has been connected through the primary winding. The voltage of +12 V supplied to the detector 14 becomes 0 V, and the detector 14 generates a privacy signal.

[Problems to be Solved by the Invention] However, in such a configuration, it is determined whether the handset 2 is in a state of calling the base unit, whether a communication path is formed with the base unit, There is a problem that it is not possible to recognize whether the road is not formed.

An object of the present invention is to provide a communication device that solves the above-mentioned problems.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes one master unit and a plurality of slave units, and includes a master unit and one slave unit. In a communication device for establishing a communication path between them and performing a telephone call, each of the slave units repeats intermittent communication in response to a first control signal and maintains a closed state in response to a second control signal. A switching unit, a display unit connected in series with the switching unit, and one of the first and second control signals in response to the input of the call path establishment request signal generated by the operation of the slave unit. One of the control signals is supplied to the switching means, and when a communication path is formed between the master unit and the slave unit, the first control signal is transmitted in response to a communication path establishment completion signal generated by the master unit. And the other of the second control signal
And control means for supplying to the switching means.

[Operation] According to the present invention, when a call path establishment request signal is generated,
The control means supplies one of the first and second control signals to the switching means. For example, if the first control signal is supplied, the switching means is turned on and off, and the current supplied to the display means is also turned on and off. As a result, if there is, the display means blinks. Further, when the call path establishment end signal is supplied, the control means supplies the other of the first and second control signals to the switching means. For example, when the second control signal is supplied,
The switching means maintains the closed state. As a result, a current continuously flows through the display means. Therefore, for example, the display means blinks while the communication path establishment request signal is being generated, and the display means is lit when the communication path establishment completion signal is being generated. When the second control signal is supplied by the communication path establishment request signal and the first control signal is supplied by the communication path establishment completion signal, the display is reversed when the communication path establishment request signal is generated. The means are lit,
In the state where the call path establishment completion signal is being generated, for example, the display means blinks. Therefore, by recognizing the display state of the display means, it is possible to recognize the current state of the slave unit.

[Embodiment] FIG. 2 is a schematic block diagram of an embodiment in which the present invention is applied to a communication device for communicating between a staff room and each classroom in a school or the like. .. Are located in each classroom, for example, a room station, 24 is one of the control station 20 and the room station 22. This is an exchange for forming a communication path between the two.

The exchange 24 has a plurality of line units 26, 26,..., And each line unit 26 is connected to one control station 20 and a plurality of, for example, 15 room stations 22. Reference numeral 26 is for forming a communication path between the control station 20 connected thereto and one of the plurality of room stations 22 connected thereto. Further, by connecting the line units 26 to each other, the control units 20 connected to the different line units 26 or the different line units 26 are connected to each other.
A communication path can be formed between the control station 20 and the room station 22 which are connected to the control station 20.

Reference numeral 28 denotes a local line / tie line unit.
Tie line function to connect exchanges 24 up to
It has a C / O line function for making outside line calls.

A control unit 30 controls each of the line units 26 and the office / tie line unit 28, and also controls paging and time signals.

Reference numeral 32 denotes a power supply unit for supplying power to the control unit 30, the office line / tie line unit 28, and the line unit 26. Reference numeral 34 denotes a power supply transformer unit connected to the power supply unit 32.

FIG. 3 is a block diagram of a communication channel system according to this embodiment. As is clear from FIG. 3, the room station 22 has a speaker 36 and a handset 38 which also serve as a microphone. Transmitter 42 and hybrid circuit
44 and a hook switch 46 are provided. Further, the room station 22 has a switch panel 48, which includes a call-in switch 50, a privacy switch 52, and a calling circuit 54. This switch panel 48 will be described later.

The control station 20 has a receiver 56 and a transmitter 58 provided on the handset, and a speaker 60 and a microphone 62 provided independently. Transmitter 58
Alternatively, an audio signal from a microphone is supplied to an amplifier 64 via a hook switch 63, and after being amplified there, an FM modulation circuit 66 modulates a carrier with FM. This FM modulated wave is supplied to an AM modulation circuit 68, AM-modulated according to a dial signal generated by a control circuit 72 in response to an operation of a keyboard 70, and a hybrid circuit through a band-pass filter 74.
Supplied to 76. On the other hand, the audio signal from the room station 22 supplied from the hybrid circuit 76 is supplied to the receiver 56 or the speaker 60 via the hook switch 63.

The control station 20 is connected to a communication path switch 80 via a control station circuit 78 in the line unit 26. In addition, each room station 22
Is connected to a communication path switch 80 via a line relay circuit 82, a talkback circuit 84, and a stuff handset circuit 86 in the line unit 26. By controlling the communication path switch 80, the line relay circuit 82, and the like by the control unit 30, a communication path is formed between one of the room stations 22 and the control station 20.

The office line / tie line unit 28 includes a communication line switch 88, an office line communication circuit 90, a tie line communication line switch 92,
The control unit 30 includes a tie-line communication circuit 94, and the control unit 30 includes a communication path switch 96 and a signal sound generation circuit 98. I do.

FIG. 4 is a detailed block diagram of the line unit 26,
The signal from the control station 20 is supplied to the FM demodulation circuit 10 via the power supply circuit 100, the hybrid circuit 102, and the high-pass filter 104 of the control station circuit 78.
The signal is demodulated into an audio signal in 6 and supplied to the communication path switch 80 via the low-pass filter 108. This audio signal is amplified by the power amplifier 110 of the talkback circuit 84 and supplied to the audio switch 112. If the room station 22 you are trying to talk on does not raise the handset 38,
The voice switch 112 is output by the output of the off-hook detection circuit 114.
Is connected to the power amplifier 110 and the off-hook detection circuit 114, so that the audio signal is supplied to the audio switch 116 via the off-hook detection circuit 114. This voice switch 116 is normally in a state of connecting the line relay circuit 82 and an AGC circuit 117 to be described later, but when the voice detection circuit 118 detects that a voice signal is The switch is switched to connect the relay circuit 82 and the off-hook detection circuit 114, and the audio signal supplied to the audio switch 116 is switched to the line relay circuit 8.
Supply 2 The line relay circuit 82 includes the relays 821 and 82
.. 82n (these are provided so as to correspond to the respective room stations). Of these, the voice switch 116 switches to a predetermined room station 22 via the one closed by the control unit 30. Is supplied. Note that, in FIG. 4, for simplification of the drawing, each of the relays 821, 822,... 82n is shown as being constituted by one, but actually, as shown in FIG. It consists of relays.

On the other hand, the audio signal from the predetermined room station 22 is transmitted to the A through the closed relay and the audio switch 116.
The voice signal is supplied to the GC circuit 117 and is supplied to the communication path switch 80 via the voice switch 120 which is closed by the output of the off-hook detection circuit 114.
2. The power is supplied to the control station 20 via the power amplifier 124, the hybrid circuit 102, and the power supply circuit 100.

When the handset 38 is lifted, the audio signal supplied from the control station 20 to the communication path switch 80 is amplified by the amplifier 126 in the stuff handset circuit 86 and supplied to the audio switch 112 via the hybrid circuit 128. However, since the voice switch 112 is switched to the hybrid circuit 128 side by the output of the off-hook detection circuit 114 that has detected that the handset 38 has been lifted, the voice signal from the hybrid circuit 128 is The signal is supplied to a voice switch 116 via an off-hook detection circuit 114. As described above, the voice switch 116 is switched to the off-hook detection circuit 114 by the output signal of the voice detection circuit 118 (a signal that detects that the voice signal is supplied from the control station 20 to the communication path switch 80). So
Predetermined room station via line relay circuit 82
Supplied to 22.

The audio signal from the room station 22 is supplied to the amplifier 130 via the line relay circuit 82, the audio switch 116, the off-hook detection circuit 114, the audio switch 112, and the hybrid circuit 128. Supplied to 132. The voice switch 132 is supplied with a signal obtained by inverting the output signal of the off-hook detection circuit 114 by the inverting circuit 134, and is closed by raising the handset 38. Therefore,
The output of the amplifier 130 is supplied to the communication path switch 80, and then to the control station 20 as described above.

Also, each relay 821, 822 ... 82 of each line relay circuit 82
, n are provided with call-in / privacy signal detection circuits 1361, 1362,. These call-in / privacy signal detection circuits 1361, 1362 ... 136n
Is a latch circuit 138 corresponding to a signal from the control unit 30.
From the room station 22.
Is supplied to the control unit 30 via the scan data bus 139. Similarly, the dial detection circuit 140 in the control station circuit 78 is sequentially scanned by the signal from the latch circuit 138, and when a dial signal is transmitted from any of the room stations 22, this is transmitted to the control unit 30 by the scan data bus 139. Feed through.

FIG. 1 is a detailed block diagram of the calling circuit 54, the handset 38 and each call-in / privacy circuit according to the gist of the present invention. Note that a total of n call-in / privacy circuits 1361 to 136n are provided, but all have the same configuration.
Only 61 is shown in FIG. The calling circuit 54 has A,
It has four terminals H, B, and C, and terminal A is actually 2 terminals.
It is connected to the relay 821a of the line relay circuit 821 composed of two relays 821a and 821b. The relay 821a connects the terminal A to the photocoupler 142 for call-in signal detection in a normal state, and connects to the transmission line 144 when the control unit 30 connects the first room station 22 and the control station 20. Connect terminal A. Terminal B is
The line relay 821 is connected to the relay 821b. In a normal state, the relay 821b connects the terminal B to the photocoupler 146 for privacy detection, and the control unit 30
Room station 22 and control station 20
Is connected to the terminal B on the transmission line 148 side.
The terminal H is connected to a first input of a control circuit 152 via a resistor 150, and the call-in switch 50 is connected between the first input of the control circuit 152 and the terminal A. The call-in switch 50 is a self-returning normally open switch. A resistor 153 is connected between a first input of the control circuit 152 and the terminal C, and the terminal C is grounded. Also,
The terminal B is connected to a second input of the control circuit 152.
The input is connected to the terminal C via the privacy switch 52 and the light emitting diode 154. The privacy switch 52 is a normal open / close switch. Control circuit 152
Is supplied to switching means, for example, an oscillation circuit 156. The oscillation circuit 156 is connected between terminals A and C in series with a display means, for example, a light emitting diode 158.

The control circuit 152 and the oscillation circuit 156 are specifically configured as shown in FIG. 5, and when the call-in switch 50 is momentarily closed to form a communication path between the slave unit and the master unit. , The control circuit 152 sends a signal to the oscillation circuit 156 to activate it. That is, in the state shown in FIG. 1, the terminals A and B are connected to the + through the photocouplers 142 and 146 and the relays 821a and 821b.
A voltage of V is applied. Therefore, the series circuit of the oscillation circuit 156 and the light emitting diode 158 includes the photocouplers 142 and 146,
Since it is connected to + V through the relay 821a and grounded through the terminal C, a DC voltage is supplied to this series circuit. The momentary closing of the call-in switch 50 causes a gate current to flow through the thyristor 160 in the control circuit 152 to make it conductive. At this time, transistor 16
2, a base current flows, and the emitters of the transistors 164 and 166 forming the astable multivibrator are grounded. At this time, when + V is applied to the terminal B, the transistor 168 is also turned on, and the transistor 170 is turned off. Accordingly, the astable multivibrator starts to operate, the light emitting diode 158 blinks, and in response, the current flowing through the photocoupler 142 becomes intermittent as shown in FIG. 6 (a). As described above, when the call-in switch 50 is operated to establish a communication path, a current flows through the thyristor 160 as a communication path establishment request signal, causing the transistor 162 to conduct and the transistor 170 to conduct, that is, the first current. A control signal is supplied to the oscillation circuit. It should be noted that a large amount of current flows at the moment when the call-in switch 50 is closed as indicated by a symbol a in FIG.
This is because the current flows through the resistor 153 only during this period.

When the call-in signal is supplied from the photocoupler 142 to the control unit 30 in this manner, the ringing tone and the number of the room station 22 are output to the corresponding control station 20, and the control station 20 performs a response operation (the handset of the control station 20). By lifting or pressing the PTT switch located in the keyboard 70.)
a and 821b are switched to the transmission lines 144 and 148, respectively. As a result, a voltage of + V is applied to the terminal A via the winding of the transformer 170 of the off-hook detection circuit 144 and the line relay 821a, and the current is changed to the light emitting diode 158, the oscillation circuit 156,
The current flows to the terminal C, and the light emitting diode 158 continues the blinking operation. Further, the switching of the line relay 821b lowers the voltage at the terminal B from + V to 0V, and the transistor 168 shown in FIG. 5 is turned off. Therefore, no current flows to the thyristor 160, the transistor 162 is turned off, and the astable multivibrator stops.
However, since the transistor 168 is turned off, the transistor 170 is turned on, current flows through the light-emitting diode 158 and the transistor 170, and the light-emitting diode 158 changes from a blinking state to a lighting state. That is, the voltage of the terminal B of the calling circuit 54 is changed as a communication path establishment completion signal by the switching of the relay 821b due to the establishment of the communication path.
The voltage drops to 0 V and is supplied to the control circuit 152. Control circuit 152
Cuts off current supply to the transistor 162 and supplies current to the transistor 170 as a second control signal. As a result, the oscillation circuit 156 is closed, and the light emitting diode 158 is turned on from the blinking state. Since the light emitting diode 158, which has been blinking, changes to the lighting state in this manner, it is found that the room station 22 has formed a communication path with the control station 20.

The communication path is formed in this way, and the communication is performed. When the communication is completed, the control unit 30 controls the communication switch 80 and the line relay circuit 82. As a result, relay 821a,
The 821b switches the terminals A and B to connect to the photocouplers 142 and 146, respectively, so that the voltage at the terminal B changes from 0V to +
V, the transistor 168 shown in FIG. 5 is turned on, the transistor 170 is turned off, the light emitting diode 158 is turned off, and it is determined on the side of the room station 22 that the call has ended.

When the call-in switch 50 is continuously closed in the state shown in FIG.
The 156 astable multivibrator is activated, the light emitting diode 158 flashes, and current flows through the call-in switch 50 and the resistor 153. As a result, while the call-in switch 50 is continuously closed as shown by reference numeral b in FIG.
53) flows through the photocoupler 142, and in addition to this, while the current flows through the astable multivibrator,
The operating current is superimposed on the above-mentioned current as shown by the symbol c. Therefore, in the photocoupler 142, while the call-in switch 50 is continuously closed, a current equal to or greater than a certain value flows, and the control unit 30 detects this. For example, if it continues for 3 seconds or more, the control unit 30 determines that a priority signal has been generated.

When the handset 38 is lifted, the switch 46b of the hook switch 46 of the handset 38 is closed, and the photocoupler 142, the line relay 821a, the terminal A1, the switch 46b of the handset 38, the terminal H of the calling circuit 54, the resistor 150,
153, a current flows through the terminal C, and the thyristor 16 of the control circuit 152
The gate current flows to 0, the oscillation circuit 156 operates as described above, the light emitting diode 158 blinks, and the current flows intermittently to the photocoupler 142. In addition, FIG.
At this time, the current flowing through the photocoupler 142 is shown. The reason why the minute current always flows as indicated by the symbol d is that the current continuously flows through the resistors 150 and 153.
If the threshold value of the photocoupler 142 is set to be larger than the minute current, the current flows substantially intermittently through the photocoupler 142, and the control unit 30 detects this as a call-in signal. The ringing tone and the number of the room station 22 are output to the corresponding control station 20, and the response operation of the control station 20 (lifting the handset of the control station 20 or pressing the push button of the keyboard 70) allows the line relay to be performed. When switching between 821a and 821b, the line relay 821a from the winding 170a of the transformer 170 of the off-hook detection circuit 144,
A current flows through the terminal A, the light emitting diode 158, the oscillation circuit 156, and the terminal C, and the terminal A1, the hybrid circuit 44, and the switch 46a of the hook switch 46 of the handset 38.
Side is switched to the hybrid circuit 44 side. ), The line relay 821b, the transmission line 148, the winding 170b of the transformer 170, the resistor 171 and the photocoupler 172. Photocoupler 172
That the handset 38 has been lifted. At this time, the voltage of the terminal B is reduced from + V to a voltage drop by the resistor 171 and the photocoupler 172.
158 is turned on.

Next, in the state shown in FIG. 1, when the privacy switch 52 is closed, the photocoupler 146, the relay 821b, the terminal B, the privacy switch 52, the light emitting diode 154,
A current flows to the terminal C, the light emitting diode 154 is turned on, and it can be seen on the room station side that a privacy instruction is given. On the other hand, the photocoupler 146 has
As shown in FIG. 6 (d), a current continuously flows, and by detecting this, the control unit 30 knows that the privacy request has been made.

In the above embodiment, the light-emitting diode 158 blinks when the call-in signal is generated, and the light-emitting diode 158 is turned on when the priority signal is emitted. The light emitting diode 158 can be turned on and off when the priority signal is emitted. For this purpose, for example, the transistor 17 shown in FIG.
The base of 0 may be connected to the cathode side of the thyristor 160, and the base of the transistor 162 may be connected to the collector of the transistor 168. In addition, although photocouplers 142 and 146 were used,
Instead, for example, an impedance element such as a resistor can be used.

[Effects of the Invention] As described above, according to the present invention, a state in which a call path is requested to be opened (in the embodiment, the call-in switch 50 is momentarily operated) and a state in which a call path is opened Is completed (the state in which the line switch 82 is switched in the embodiment) and the display means (the light emitting diode 15 in the embodiment).
Since the display state of 8) is different, it can be easily recognized on the side of the slave unit (in the embodiment, the room station 20) whether it is in the call path establishment request state or the call path establishment end state. When the display means is not lit or flashing, the master unit (in the embodiment, the control station)
It can recognize that it is waiting for the call from 20).

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of an embodiment of a communication device according to the present invention, FIG. 2 is a system configuration diagram of the embodiment, FIG. FIG. 5 is a detailed circuit diagram of a main part of the embodiment, FIG. 6 is a timing diagram for explaining the operation of the embodiment, and FIG. It is a block diagram. 20: control station (master), 22: room station (child), 152: control circuit, 156: oscillation circuit (switching means), 158: light emitting diode (display means).

Continued on the front page (72) Inventor Mitsuo Nakamura 7-2-1, Minatojima-Nakamachi, Chuo-ku, Kobe-shi, Hyogo Inside TOA Co., Ltd. (72) Inventor Akemi Tarutani 7-2-1, Minatojima-cho, Chuo-ku, Kobe-shi, Hyogo No. TOA Co., Ltd. (56) References JP-A-60-180296 (JP, A) JP-A-63-242018 (JP, A) JP-A-1-135172 (JP, A) JP-A-2-70163 (JP, A) JP-B-61-43897 (JP, B2) US Patent 4,744,103 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04Q 3/58 H04M 1/00 H04M 3 / 06 H04M 3/42 H04M 9/00-9/10 H03K 3/282 H03K 17/296

Claims (1)

(57) [Claims] A communication device having one master unit and a plurality of slave units, forming a communication path between the master unit and the one slave unit, and performing a call. A switching unit that switches on and off in response to the first control signal and maintains a closed state in response to the second control signal; a display unit connected in series with the switching unit; In response to the input of the call path establishment request signal generated by the operation of the slave unit, a control signal of one of the first and second control signals is supplied to the switching means,
When a communication path is formed between the master unit and the slave unit,
A communication unit comprising: a control unit that supplies the other of the first and second control signals to the switching unit in response to a communication path establishment completion signal generated by the master unit.