JP3414036B2 - Door phone equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intercom system for transmitting and receiving signals between a slave unit installed at a front door and a master unit installed in a living room.

[0002]

2. Description of the Related Art FIG. 11 is a block diagram showing an intercom system according to a conventional example. The child device 1 installed at the entrance of the building or the like is connected to the parent device 2 installed in the room or the like of the building by cables Ca1 and Ca2. The cordless handset 1 has a conversation with a resident in the building and informs an external situation such as a fire in the building to the outside of the building.
A, camera unit 1B, video FM modulation circuit 1C
, Video transmission circuit 1D, microphone 1E, speaker 1F
A voice transmission / reception circuit 1G, a call button 1H, a demultiplexing circuit 1I, and an alarm indicator light LED. Here, the power supply circuit 1A supplies the DC power separated by the demultiplexing circuit 1I to each circuit except for its own warning indicator LED. The camera unit 1B is for taking an image of a visitor and transmitting it as a video signal to the video FM modulation circuit 1C. The video FM modulation circuit 1C FM-modulates the input video signal and transmits it as a video FM signal to the video transmission circuit 1D. The video transmission circuit 1D amplifies the input video FM signal and transmits it to the demultiplexing circuit 1I. The microphone 1E is for transmitting the voice of the visitor to the voice transmitting / receiving circuit 1G as a voice signal. Speaker 1
F reproduces the voice signal input from the base unit 2 via the voice transmission / reception circuit 1G as voice. The voice transmission / reception circuit 1G amplifies the voice signal input from the microphone 1E and transmits it to the demultiplexing circuit 1I, and also amplifies the voice signal transmitted from the master device 2 and transmits it to the speaker 1F. . The call button 1H transmits a call signal to the demultiplexing circuit 1I to inform the resident of the building of the presence of the visitor when operated by the visitor. Demultiplexing circuit 1
I multiplexes a signal in the cable Ca1 with a video FM signal, an audio signal, and a calling signal and transmits the multiplexed signal to the master unit 2, and separates the audio signal and the DC power source multiplexed and transmitted from the master unit 2. Voice transmission / reception circuit 1G and power supply circuit 1A
And is connected to the cordless handset 1 side of the cable Ca1. The alarm indicator light LED is for notifying the outside of the building that an emergency has occurred in the building, and is turned on or blinks when DC power is supplied from the base unit 2 via the cable Ca2.

The base unit 2 includes a power supply circuit 2A, a demultiplexing circuit 2B, a video receiving circuit 2C, and a video FM demodulating circuit 2D.
, Monitor unit 2E, voice transmission / reception circuit 2F, handset 2G, ringing signal detection circuit 2H, ringing tone generation circuit 2I, speaker 2J, switch 2K, sensor input interface 2L, and alarm reception circuit 2M.
An alarm sound generating circuit 2N, an indicator 20, a reset switch 2Q, and an alarm indicator light driving circuit 2R. Here, the power supply circuit 2A is connected to a commercial power supply (not shown), supplies DC power for operating each circuit of the master unit 2, and also supplies DC power to the slave unit 1 via the cable Ca1. To supply. Demultiplexing circuit 2B
Is the cable Ca transmitted from the slave unit 1 after being multiplexed.
Separate the video FM signal, audio signal, and ringing signal in 1
The signal is transmitted to the video receiving circuit 2C, the voice transmitting / receiving circuit 2F, and the calling signal detecting circuit 2H, and the signal in the cable Ca1 is multiplexed with the voice signal from the voice transmitting / receiving circuit 2F and transmitted to the handset 1. . The video receiving circuit 2C receives the video FM signal extracted by the demultiplexing circuit 2B and sends it to the video FM demodulation circuit 2D. The video FM demodulation circuit 2D receives the video FM input from the video reception circuit 2C.
The signal is demodulated and transmitted as a video signal to the monitor unit 2E. The monitor unit 2E displays an image of the video signal input from the video FM demodulation circuit 2D. The voice transmitting / receiving circuit 2F receives the voice signal from the handset 1 separated by the demultiplexing circuit 2B and transmits it to the handset 2G, and also amplifies the voice signal from the handset 2G and transmits it to the demultiplexing circuit 2B. It is a thing. The handset 2G includes the voice transmitting / receiving circuit 2 from the handset 1.
The voice signal transmitted via F is reproduced as voice, and the voice of a resident or the like is transmitted as a voice signal to the voice transmitting / receiving circuit 2F. Ring signal detection circuit 2H
Detects the ringing signal separated by the demultiplexing circuit 2B and transmits it to the ringing tone generating circuit 2I. When the ringing signal is input from the ringing signal detecting circuit 2H, the ringing tone generating circuit 2I generates a ringing tone and transmits it to the speaker 2J. The speaker 2J has a ringing tone generation circuit 2I.
The ringing sound and the alarm sound generation circuit 2N generate an alarm sound. The alarm receiving circuit 2M is used when a resident or the like operates the switch 2K due to an emergency situation in the living room or when a fire sensor or the like (not shown) is activated and the sensor input interface 2L receives an input. The alarm signal is transmitted to the alarm sound generation circuit 2N, the display device 20 and the alarm indicator lamp drive circuit 2R. When the alarm signal is input from the alarm receiving circuit 2M, the alarm sound generating circuit 2N generates an alarm sound and transmits it to the speaker 2J. The display unit 20 displays the alarm content based on the alarm signal from the alarm receiving circuit 2M. The reset switch 2Q releases an emergency. When the alarm signal is input from the alarm receiving circuit 2M, the alarm indicator light drive circuit 2R receives the alarm indicator light L via the cable Ca2.
DC power is supplied to the ED.

The operation of the conventional example will be described below. During standby (there is no guest), the base unit 2 uses the power supply circuit 2A to operate the circuits of the handset 1 at a low voltage (for example, 6
V) DC power is supplied to each circuit of the cordless handset 1, and the call button 1
Wait for H operation.

When the customer operates the call button 1H of the handset 1 at the time of the visitor, the call signal generated by the visitor is the demultiplexing circuit 1I.
In the main unit 2, as a voltage change (for example, 2 V instantaneously) of the DC power source in the cable Ca1
Sent to. When the calling signal separated by the demultiplexing circuit 2B is detected by the calling signal detection circuit 2H, the base unit 2 causes the calling sound generation circuit 2I to generate a calling sound and cause the speaker 2J to ring. Then, the master device 2 has the cable Ca1.
When the voltage of the internal DC power supply changes, a high-voltage (for example, 24V) DC power supply for operating each circuit of the child device 1 is supplied from the power supply circuit 2A to each circuit of the child device 1.

When each circuit of the child device 1 is activated, the child device 1
Is an image of a visitor or the like taken by the camera unit 1B and transmitted as a video signal to the video FM modulation circuit 1C, modulated and transmitted as a video FM signal to the video transmission circuit 1D, amplified, and then transmitted to the demultiplexing circuit 1I. Sent. Demultiplexing circuit 1I
Then, the input video FM signal is multiplexed and transmitted to the master unit 2.

The master unit 2 separates the video FM signal transmitted from the slave unit 1 by the demultiplexing circuit 2B, and when received by the video receiving circuit 2C, demodulates the received video FM signal into the video FM demodulation. It is demodulated by the circuit 2D and transmitted as a video signal to the monitor unit 2E for image display.

[0008] Then, the resident in the living room has a handset 2G.
Ringing tone generation circuit 2I
Is stopped and the ringing from the speaker 2J is stopped, and a communication path is formed between the slave 1 and the master 2. The voice of a visitor or the like is input to the demultiplexing circuit 1I as a voice signal via the microphone 1E and the voice transmitting / receiving circuit 1G. The demultiplexing circuit 1I multiplexes the input audio signal in the cable Ca1 and transmits it to the master unit 2.

In the master unit 2, the demultiplexing circuit 2B separates the multiplexed and transmitted voice signals and reproduces them with the handset 2G through the voice transmitting / receiving circuit 2F, and the voice of the resident in the living room is It is input to the demultiplexing circuit 2B via the handset 2G and the voice transmitting / receiving circuit 2F.
The demultiplexing circuit 2B outputs the input audio signal to the cable C.
It is multiplexed in a1 and transmitted to the handset 1.

In the handset 1, the demultiplexing circuit 1I separates the multiplexed and transmitted voice signal, and reproduces it by the speaker 1F via the voice transmitting / receiving circuit 1G.

At the end of the call, the resident in the living room operates the handset 2G on the hook to operate the power supply circuit 2A.
Is a low voltage (for example, 6
Switch to the DC power supply of V) and return to the standby state.

On the other hand, when an emergency occurs in the living room and a resident operates the switch 2K or inputs the sensor input interface 2L, the alarm receiving circuit 2M is activated and an alarm signal is output by the alarm sound generating circuit 2N. , The indicator 2O and the alarm indicator light drive circuit 2R. Alarm sound generation circuit 2N
When an alarm signal is input, generates an alarm sound and causes the speaker 2J to ring, and the display 20 displays the alarm content based on the alarm signal. The alarm indicator light drive circuit 2R is
When the alarm signal is input, DC power for lighting or blinking the alarm indicator LED is supplied via the cable Ca2, and the alarm indicator LED of the cordless handset 1 is connected to the cable Ca.
It is turned on or blinks when a DC power is supplied via 2. Then, when the emergency situation is resolved, by operating the reset switch 2Q, the alarm indicator lamp drive circuit 2R stops the supply of the DC power to the alarm indicator lamp LED and turns on or blinks the alarm indicator lamp LED. At the same time, the speaker 2J stops ringing.

[0013]

However, in the door intercom apparatus having the above-described structure, the voice signal and the video FM signal are multiplexed in the DC power supply in the cable Ca1, and the call signal from the slave unit 1 is transmitted. Since the master unit 2 detects the change in the voltage of the DC power supply, the change of the voltage of the DC power supply controls the blinking or lighting of the alarm display light LED so that the alarm display light drive circuit 2R outputs the alarm display light L.
Since superimposing the DC power supply to the ED on the cable Ca1 causes a malfunction of the call signal detection, the cable C for supplying the DC power to the alarm indicator LED is
It was necessary to provide a2 with separate wiring.

However, when the cable Ca2 is provided as a separate wiring, incorrect wiring may be caused, and the wiring work may be complicated.

The present invention has been made in view of the above points, and an object thereof is to provide an intercom system which can issue an alarm without causing a malfunction by using the same cable. Especially.

[0016]

The invention according to claim 1 is
An audio transmitter / receiver circuit for transmitting and receiving an audio signal, a slave unit having a demultiplexing circuit for transmitting and transmitting a multiplexed transmission signal, and a demultiplexing circuit for separating a reception signal, an audio transmission and reception circuit for transmitting and receiving an audio signal, and a transmission signal And a master unit having a demultiplexing circuit for demultiplexing received signals and transmitting the signals by multiplexing them with each other through a transmission line. In the doorphone device configured to transmit and receive the converted signal, the master unit detects an emergency and transmits an alarm signal, and an alarm signal is output from the alarm transmission circuit. A carrier generation circuit for generating a carrier signal having a frequency that does not affect a voice signal is added, and the slave unit has a carrier detection circuit for detecting the carrier signal, an alarm output circuit for issuing an alarm, and the key. An alarm drive circuit for driving the alarm output circuit when the carrier signal is detected by the rear detection circuit is added, and the master unit multiplexes the carrier signal output from the carrier generation circuit by the demultiplexing circuit. Transmitted to the slave unit, the slave unit detects the carrier signal separated by the demultiplexing circuit by the carrier detection circuit, and the alarm drive circuit based on the carrier signal detected by the carrier detection circuit. The alarm output circuit is driven by, and the alarm is output by the alarm output circuit.
An intercom device, the carrier detection circuit and an alarm
The drive circuit is composed of a filter circuit, and the carrier signal
Amplitude voltage is sufficient to drive the alarm output circuit
It is characterized by using a voltage .

According to a second aspect of the invention, in the intercom apparatus according to the first aspect, a video FM modulating circuit for modulating a captured video signal, an audio transmitting / receiving circuit for transmitting / receiving an audio signal, and a transmission signal multiplexed for transmission. In addition, a slave unit including a demultiplexing circuit that separates a received signal, a video FM demodulation circuit that demodulates a modulated video signal, an audio transmission / reception circuit that transmits / receives an audio signal, and a transmission signal is multiplexed. A master unit having a demultiplexing circuit that separates the received signal from the master unit via a transmission line, and is multiplexed by the demultiplexing circuit between the master unit and the slave unit. In the doorphone device configured to transmit and receive a signal, the master unit, an alarm transmission circuit that detects an emergency and transmits an alarm signal, and an alarm signal is output from the alarm transmission circuit,
A carrier generation circuit that generates a carrier signal having a frequency that does not affect the audio signal and the modulated video signal is added, and the slave unit has a carrier detection circuit that detects the carrier signal and an alarm that issues an alarm. An output circuit and an alarm drive circuit for driving the alarm output circuit when the carrier detection circuit detects the carrier signal are additionally provided.

[0018]

According to a third aspect of the present invention, in the intercom apparatus according to the first aspect or the second aspect, the carrier generation circuit generates a plurality of carrier signals having different frequencies, and the carrier detection circuit. In the above, the plurality of carrier signals are detected, and the alarm output circuit issues a plurality of types of alarms based on the plurality of carrier signals.

According to a fourth aspect of the present invention, in the intercom apparatus according to the first to third aspects, the alarm output circuit has a structure in which two light emitting diodes are connected in parallel in opposite directions. To do.

[0021]

According to the invention of claim 1 or 2 , the carrier generation circuit generates a carrier signal having a frequency that does not affect the audio signal and the video signal, and the slave unit receives the carrier signal transmitted from the master unit. An alarm is output by an alarm output circuit based on a signal, and an alarm can be issued by transmitting a carrier signal using the same transmission line as an audio signal or a video signal.

According to a third aspect of the present invention, in the intercom system according to the first aspect or the second aspect of the invention, the carrier generation circuit outputs a plurality of carrier signals having different frequencies corresponding to the types of alarms. The carrier detection circuit detects multiple carrier signals, and the alarm output circuit issues an alarm based on the carrier signal, and the slave unit issues multiple types of alarms based on the content of the emergency. You can

According to a fourth aspect of the present invention, in the intercom apparatus according to the first to third aspects, the alarm output circuit is
It has a structure in which two light emitting diodes are connected in parallel in opposite directions, and corresponds to the positive and negative periods of the carrier signal,
The two light emitting diodes are alternately turned on and the brightness is increased to improve the visibility of the alarm display.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A reference example of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of a doorphone device according to a reference example of the present invention. The same parts as those shown in FIG. 11 as a conventional example are designated by the same reference numerals and the description thereof will be omitted. Carrier detection circuit 1J
Is for detecting a carrier signal, which will be described later, separated by the demultiplexing circuit 1I. The alarm drive circuit 1K generates a voltage for operating the alarm output circuit 1L when a carrier signal is detected by the carrier detection circuit 1J.
A multivibrator or an integrating circuit is used. The alarm output circuit 1L notifies the outside of the building of an emergency in the building, and as shown in FIG. 2, a light emitting diode that blinks or continuously lights up based on the voltage generated by the alarm drive circuit 1K. 1ed, and a diode D connected in parallel with the light emitting diode 1ed in the opposite direction.
The diode D is for protecting the light emitting diode 1ed from application of a reverse voltage.

When the alarm signal is input from the alarm reception circuit 2M, the carrier generation circuit 2P of the master unit 2 generates a carrier signal and transmits it to the demultiplexing circuit 2B. FIG. 3 is a schematic diagram showing an example of a carrier signal according to this reference example, and FIG. 4 is a schematic diagram showing an example of transmission of a carrier signal. The carrier generation circuit 2P, as shown in FIGS. 3 and 4, has a frequency (for example, 30
A carrier signal of KHz) is generated and transmitted to the demultiplexing circuit 2B so that a time T1 when the carrier signal is transmitted and a time T2 when the carrier signal is not transmitted are repeated.

The operation of this reference example will be described below.
The operation during standby (when there is no customer), when a customer arrives, and the alarm sound generation circuit 2N and the display 2O are the same as the operations shown in the conventional example, and therefore the description thereof is omitted here. When the alarm signal is input from the alarm receiving circuit 2M, the carrier generating circuit 2P generates a carrier signal having a frequency (for example, 30 KHz) that does not affect the audio signal as shown in FIG. 4 and transmits the carrier signal to the demultiplexing circuit 2B. To do. Demultiplexing circuit 2B
Transmits the input carrier signal to the slave unit 1 after multiplexing it with the signal in the cable Ca1.

In the handset 1, the demultiplexing circuit 1I separates the multiplexed and transmitted carrier signals, and when the separated carrier signal is detected by the carrier detection circuit 1J, the alarm drive circuit 1K outputs an alarm. A voltage for driving the output circuit 1L is generated, and the light emitting diode led of the alarm output circuit 1L lights up based on the voltage generated by the alarm drive circuit 1K.

Here, the light emitting diode led of the alarm output circuit 1L lights up only when the carrier signal is transmitted from the master unit 2, and the time T1 when the carrier signal is transmitted and the time T2 when the carrier signal is not transmitted are repeated. The blinking will occur.

Therefore, in the present reference example, the carrier signal transmitted when an emergency occurs is set to a frequency that does not affect the voice signal, so that the base unit 2 sends the ringing signal to the DC signal. When it is detected as a change in the voltage of the power supply, the carrier signal for issuing an alarm is not mistakenly determined as a calling signal, and the doorphone device can be prevented from malfunctioning.

In this reference example, the time T1 when the carrier signal is transmitted and the time T2 when the carrier signal is not transmitted.
The carrier generating circuit 2P is set to repeat the above, but the present invention is not limited to this, and the carrier signal is constantly transmitted so that the light emitting diode 1e
You may make it light continuously d. Also, ginseng
In considered example, blinking or continuous lighting setting of the light emitting diode 1ed was conducted in the carrier generating circuit 2P, need not be limited thereto, may be set by the alarm driver circuit 1K. Further, in the present reference example, the light emitting diode 1ed is blinked or continuously turned on in the alarm output circuit 1L, but the invention is not limited to this, and the outside of the building is notified by voice or the like. Good.

FIG. 5 is a block diagram showing an example of a doorphone device according to another reference example of the present invention. In the block diagram shown in this reference example, a camera unit 1B, a video FM modulation circuit 1C, and a video transmission circuit 1D are added to the slave device 1 side of the block diagram shown in FIG. 1, and a video reception circuit 2C is added to the master device 2 side. A video FM demodulation circuit 2D and a monitor unit 2E are added, and the video is further transmitted in the above-mentioned reference example. In this reference example, as shown in FIG. 6, a carrier signal having a frequency (for example, 30 KHz) that does not affect the audio signal and the video FM signal is generated by the carrier generation circuit 2P, and the demultiplexing circuit 2B causes When the carrier detecting circuit 1J detects the carrier signal separated by the demultiplexing circuit 1I, the alarm driving circuit 1K
Drives the alarm output circuit 1L to blink or continuously light.

[0032] Thus, also in the present embodiment, as with Reference <br/> the above example, transmitting by multiplexing a carrier signal to mobile terminal 1 by using the cable Ca1 for transmitting and receiving an audio signal and a video FM signal The alarm can be issued by the alarm output circuit 1L of the child device 1.

In the present reference example, only one carrier signal is generated by the carrier generation circuit 2P, but the present invention is not limited to this, and as shown in FIG. In the two carrier generation circuits 2Pa and 2Pb, carrier signals of different frequencies are generated according to the type of emergency (for example, the operation of the switch 2K or the input to the sensor input interface 2L), and the first and second carrier devices 1 are generated. The carrier detection circuits 1Ja and 1Jb may detect a predetermined carrier signal so that an emergency can be determined.

Further, in the above reference example, the carrier signals generated by the carrier generation circuits 2P, 2Pa, 2Pb of the base unit 2 are converted into the carrier detection circuits 1J, 1Ja of the handset unit 1.
Alarm output circuits 1L, 1La, 1L detected by 1Jb and generated by the alarm drive circuits 1K, 1Ka, 1Kb
Although the light emitting diode 1ed of b is blinked, the invention is not limited to this, and one embodiment of the present invention shown in FIGS.
As described above, a predetermined carrier signal is detected using the filter circuits 1M, 1Ma, and 1Mb, and as shown in FIG. 3, a voltage E that is half the amplitude voltage of the carrier signal is detected.
However, the voltage at which the light emitting diode 1ed emits light (for example, 1.
By setting a sufficiently large voltage (for example, 2V) with respect to 5V, the alarm drive circuits 1K, 1Ka, and 1Kb can be made unnecessary.

Further, in the embodiment shown in FIGS. 8 and 9,
Although the alarm output circuit 1L is composed of the light emitting diode led and the diode D, the alarm output circuit 1L is not limited to this.
As shown in, a light emitting diode led 'is provided instead of the diode D, and the light emitting diode led' emits light for the positive half wave of the carrier signal and the light emitting diode led 'emits light for the negative half wave. Thus, the brightness may be increased to improve the visibility of the alarm display.

[0036]

The invention according to claim 1 or 2 is
In the carrier generation circuit, it is possible to generate a carrier signal of a frequency that does not affect the audio signal and the video signal, multiplex it with other signals, and send it on the same transmission line, so it is possible to achieve wire saving. Provided is a doorphone device that can be easily maintained and can perform an alarm without causing a malfunction even when a carrier signal is transmitted using the same transmission line as a transmission line for transmitting an audio signal or a video signal. We were able to.

According to a third aspect of the present invention, in the intercom apparatus according to the first aspect or the second aspect, the carrier generation circuit generates a plurality of carrier signals having different frequencies, and the carrier detection circuit generates a plurality of carrier signals. The carrier signal of
The alarm output circuit issues an alarm based on a plurality of carrier signals, and the slave unit can issue a plurality of types of alarms based on the contents of the emergency.

According to a fourth aspect of the present invention, in the intercom apparatus according to the first to third aspects, the alarm output circuit is 2
Two light-emitting diodes are connected in parallel in opposite directions.
The two light emitting diodes are alternately turned on to increase the brightness and improve the visibility of the alarm display.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a doorphone device according to a reference example of the present invention.

FIG. 2 is a circuit diagram showing an example of an alarm output circuit in the above figure.

FIG. 3 is a schematic diagram showing an example of a carrier signal according to the present reference example.

FIG. 4 is a schematic diagram showing an example of transmission of a carrier signal according to the present reference example.

FIG. 5 is a block diagram showing an example of a doorphone device according to another reference example of the present invention.

FIG. 6 is a schematic diagram showing an example of transmission of a carrier signal according to the present reference example.

FIG. 7 is a block diagram showing an example of a doorphone device according to another reference example of the present invention.

FIG. 8 is a block diagram showing an example of a doorphone device according to an embodiment of the present invention.

FIG. 9 is a block diagram showing an example of a doorphone device according to another embodiment of the present invention.

FIG. 10 is a schematic diagram showing an example of an alarm output circuit according to another embodiment of the present invention.

FIG. 11 is a block diagram of a doorphone device according to a conventional example.

[Explanation of symbols]

1 child machine 1A power circuit 1B camera unit 1C video FM modulation circuit 1D video transmission circuit 1E microphone 1F speaker 1G voice transmission / reception circuit 1H call button 1I demultiplexing circuit 1J carrier detection circuit 1Ja First carrier detection circuit 1Jb Second carrier detection circuit 1K alarm drive circuit 1Ka First alarm drive circuit 1Kb Second alarm drive circuit 1L alarm output circuit 1La First alarm output circuit 1Lb Second alarm output circuit 1M filter circuit 1Ma first filter circuit 1 Mb second filter circuit 2 parent machine 2A power supply circuit 2B demultiplexing circuit 2C video receiving circuit 2D video FM demodulation circuit 2E monitor unit 2F voice transmission / reception circuit 2G handset 2H ringing signal detection circuit 2I Ring generating circuit 2J speaker 2K switch 2L sensor input interface 2M alarm receiving circuit 2N alarm sound generation circuit 2O indicator 2P carrier generation circuit 2Pa First carrier generation circuit 2Pb Second carrier generation circuit 2Q reset switch 2R alarm indicator light drive circuit LED warning indicator light led, led 'light emitting diode D diode Ca1, Ca2 cable

Front Page Continuation (72) Inventor Yoshihiro Tanigawa 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) Reference JP-A-3-83446 (JP, A) JP-A-2-284563 (JP, A) ) JP-A-5-83762 (JP, A) JP-A-52-116097 (JP, A) Actual development S59-59065 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G08B 25/04 H04M 9/00 H04N 7/18

Claims (4)

(57) [Claims] 1. A handset comprising a voice transmitting / receiving circuit for transmitting / receiving a voice signal, a demultiplexing circuit for transmitting a multiplexed transmit signal, and separating a received signal, and a voice transmitting / receiving for transmitting / receiving a voice signal. A circuit and a master device having a demultiplexing circuit that multiplexes and transmits a transmission signal and separates a reception signal are connected via a transmission line, and between the master device and the slave device, In an intercom device that transmits and receives signals multiplexed by a demultiplexing circuit, an alarm transmission circuit that detects an emergency and transmits an alarm signal to the master unit, and an alarm signal is output from the alarm transmission circuit Then, a carrier generation circuit for generating a carrier signal having a frequency that does not affect the voice signal is added, and the slave unit has a carrier detection circuit for detecting the carrier signal and an alarm output circuit for issuing an alarm. And a warning drive circuit for driving the warning output circuit when the carrier detection circuit detects the carrier signal, and the master unit multiplies the carrier signal output from the carrier generation circuit by the multiplexing signal. Transmitted to the slave unit after being multiplexed by the separator circuit, the slave unit detects the carrier signal separated by the multiplexer / demultiplexer circuit by the carrier detection circuit, and based on the carrier signal detected by the carrier detection circuit. An intercom system in which the alarm output circuit is driven by the alarm drive circuit and an alarm is issued by the alarm output circuit.
A.Detection circuit and alarm drive circuit are composed of filter circuit,
Driving the alarm output circuit with the amplitude voltage of the carrier signal
An intercom device characterized in that the voltage is set to be sufficient for the operation . 2. A video FM modulating circuit for modulating a captured video signal, an audio transmitting / receiving circuit for transmitting / receiving an audio signal, and a demultiplexing circuit for multiplexing and transmitting a transmission signal and separating a reception signal. And a video FM demodulation circuit that demodulates a modulated video signal, an audio transmission / reception circuit that transmits and receives an audio signal, and a demultiplexing circuit that multiplexes and transmits a transmission signal and separates a reception signal. In the intercom device, which is configured to connect the parent device having it through a transmission line, and to transmit and receive the signal multiplexed by the demultiplexing circuit between the parent device and the child device, Is an alarm transmission circuit that detects an emergency and transmits an alarm signal,
When an alarm signal is output from the alarm transmission circuit, a carrier generation circuit that generates a carrier signal having a frequency that does not affect the audio signal and the modulated video signal is added, and the carrier is connected to the carrier. A carrier detection circuit for detecting a signal, an alarm output circuit for issuing an alarm, and an alarm drive circuit for driving the alarm output circuit when the carrier detection circuit detects the carrier signal. The door phone device according to claim 1. 3. The carrier generation circuit generates a plurality of carrier signals having different frequencies, the carrier detection circuit detects the plurality of carrier signals, and the alarm output circuit detects the carrier signals based on the plurality of carrier signals. claim, characterized in that to perform a plurality of types of alarm 1 or
Intercom apparatus other claim 2. Wherein said alarm output circuit, two light emitting diodes intercom device according to claim 1 to claim 3 further characterized in that a structure connected in the reverse direction in parallel with each other.