JP3513854B2 - TV intercom system - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an intercom subunit,
The present invention relates to a TV intercom system including an intercom base unit and an intercom sub-base unit.

[0002]

2. Description of the Related Art Conventionally, television intercom systems have been widely used in general households. As shown in FIG. 6A, one intercom base unit 100 with a monitor TV is provided.
In addition, in a system having a configuration in which one intercom subunit with camera 200 is connected, by feeding power from the master unit 100 to the slave unit 200, it is possible to transmit an audio signal in both directions, and The video signal captured by the camera is
It is transmitted to the base unit 100.

When one intercom sub-master unit 300 with a monitor television is additionally connected to such a system, the configuration is as shown in FIG. 6B, and power is supplied from the master unit 100 to the slave unit 200. This enables bidirectional audio signal transmission between the slave unit 200 and the master unit 100, or between the slave unit 200 and the sub-master unit 300, and at the same time, a video signal captured by the camera of the slave unit 200. Is transmitted to the base unit 100 and the sub-base unit 300. In this system,
Each of the master unit 100 and the sub master unit 300 is configured to transmit a control signal in order to notify the other side that the call from the slave unit 200 has been answered.

FIG. 7 is a block diagram showing the internal structure of the system shown in FIG. The base unit 100 is C
The PU 110, a multiplexing circuit 111 that multiplexes a video signal and an audio signal, a power supply circuit 112 that supplies operating power to the slave 200, a call circuit 113 that includes a speaker SP100 and a microphone MI100, and a monitor TV M100 that displays video. A video circuit 114 for displaying, a power supply circuit 115 for supplying power to each unit in the master device 100, a call detection circuit 116 for detecting a call from the slave device 200, and a termination circuit 11.
7 and a call button B100 operated to answer a call from the child device 200.

On the other hand, the slave unit 200 includes a multiplexing circuit 210,
A call circuit 211 having a speaker SP200 and a microphone MI200, a video circuit 212 for processing a video image captured by the camera circuit 213, and a call signal generation circuit 214 for detecting an operation of the call button B200 and generating a call signal.
And a power receiving circuit 215 that receives power from the parent device 100.

By operating the call button B200 in the child device 200, the call detection signal 116 transmitted from the two-wire type signal line L100 to the call detection circuit 116 of the master device 100.
Is detected, the base unit 100 outputs a ringing tone and the power supply circuit 112 starts supplying power to the slave unit 200. As a result, the child device 200 is moved to the camera circuit 21.
3 is driven and the captured image is transmitted to the parent device 100.
By displaying this on the monitor TV M100 and responding by operating the call button B100 in the base unit 100, the intercom call by both call circuits 113 and 211 becomes possible.

Next, FIG. 8 is a block diagram showing the internal configuration of the system shown in FIG. 6 (b). The parent device 100 has a CPU 110 and a multiplex circuit 1 as in the configuration shown in FIG.
11, a power supply circuit 112, a call circuit 113 having a speaker SP100 and a microphone MI100, and a video circuit 114 for displaying a video on the monitor television M100.
Power supply circuit 115, call detection circuit 116, and termination circuit 1
17 and a call button B100, and further the sub-base unit 300
A control signal transmitting circuit 118 and a control signal receiving circuit 119 for transmitting and receiving a control signal to and from the communication circuit 113.
A call circuit switch SW100 that is turned on when a call is made.

The slave unit 200 has the same structure as that shown in FIG. 7, and includes a multiplexing circuit 210, a communication circuit 211 having a speaker SP200 and a microphone MI200, a video circuit 212 and a camera circuit 213, and a call button B200. And a call signal generation circuit 214 and a power receiving circuit 215.
The sub parent device 300 has the same configuration as the parent device 100, but does not include circuits corresponding to the power feeding circuit 112 and the termination circuit 117, and includes the CPU 310, the multiplex circuit 311, the speaker SP 300, and the microphone MI 300. The call circuit 313 included therein, the video circuit 314 for displaying an image on the monitor TV M300, the power supply circuit 315, the call detection circuit 316, the call button B300, and the control signal transmission circuit 31.
8 and the control signal receiving circuit 319 and the communication circuit switch S
And W300.

By operating the call button B200 in the child device 200, the call detection signal 116 transmitted from the two-wire signal line L100 to the call detection circuit 116 of the parent device 100.
When it is detected, a ringing tone is output and the power feeding circuit 1
12, the power supply to the slave 200 is started. Also,
At the same time, the ringing detection circuit 316 of the sub-base unit 300 also detects a ringing signal and outputs a ringing tone.

When the slave unit 200 receives the power supply, it drives the camera circuit 213 to transmit the photographed image to the multiplex transmission line L100. Base unit 100 and sub-base unit 30
0, the monitor circuit M by the video circuits 114 and 314.
100, M300 shows the received video, call button B
If the user responds by operating 100 or B300, the speech circuit switches SW100 and SW300 are turned on, and the speech circuits 113 and 313 cause the speech circuit 21 of the slave unit 200 to operate.
An intercom call with 1 becomes possible. At this time, the call button B10 of the main unit 100 or the sub-main unit 300
Either one of 0 and B300 that is operated and responded transmits a control signal to the other by the control signal transmission circuits 118 and 318. In the master device 100 or the sub-master device 300 that has received the control signal by the control signal receiving circuits 119 and 319,
The operation of the monitor televisions M100 and M300 is stopped, the fact that a call is in progress is displayed by a lamp or the like, and the call is prohibited while the call circuit switches SW100 and SW300 are kept in the off state. In master device 100, even if the control signal is received from sub-master device 200, power supply from power supply circuit 112 is continued in order to maintain the call in sub-master device 3.

[0011]

However, in the above-mentioned conventional TV intercom system, when it is composed of a slave unit, a master unit, and a sub-master unit (see FIG. 6B and FIG. 8), Each of the sub-base units needs a transmission / reception circuit for a control signal in order to recognize each other's operations. The manufacturing cost was higher than that of the parent machine.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a television intercom system in which it is not necessary to provide a control signal transmission / reception circuit in each of a master unit and a sub-master unit. There is.

[0013]

In order to achieve the above object, a television intercom system according to the present invention comprises a door intercom subunit with a camera and an intercom sub-master unit with a monitor television connected via a two-wire signal line. , An intercom master unit with a monitor television connected to the sub-master unit via a two-wire signal line.

According to the first aspect of the present invention, the sub-base unit is provided with a switching means for connecting the intercom slave unit and the base unit in the standby state, and when the master unit performs a call start operation, the base unit is set to the sub-base unit. When a control signal is transmitted and the sub-base unit receives the control signal, the sub-base unit transitions to the base unit talking state, and when the sub-base unit operates to start a call, the switching unit disconnects the signal line to the base unit and the intercom The device and the sub-base unit are connected to enable communication.

The operation for starting a call in the base unit and the sub-base unit includes an operation of a call button for answering a call from an intercom subunit, a hook-off operation of a call handset, and the like. According to a second aspect of the present invention, in the first aspect, the sub-main unit further includes a power feeding unit that supplies operating power to the intercom subunit, and when the switching unit connects the intercom subunit, the sub-unit is connected to the intercom subunit. Start supplying operating power. When the sub-master unit and the intercom slave are connected, the intercom slave is disconnected from the master unit, so that the intercom slave receives power supply from the sub-main unit.

According to a third aspect of the present invention, in the first or second aspect, the sub-main unit further includes voltage detection means for detecting a voltage change of the two-wire type signal line, and the voltage detected by the voltage detection means. By the change of
The response of the master unit to this call is determined. According to a fourth aspect of the present invention, in the third aspect, when the voltage detecting means determines that the intercom slave is calling, the sub-base station displays the video signal transmitted from the intercom slave on the monitor television, and then the master unit. When the response is determined, the operation of the monitor TV is stopped and the call is disabled.

According to a fifth aspect of the present invention, in the third aspect, the sub-master unit displays the video signal transmitted from the intercom sub-unit on the monitor television when the voltage detection means determines that the intercom sub-unit is called. When the response of the sub-master unit is detected, the switching means switches the connection of the intercom subunit to the sub-master unit side. In claim 6, claim 1
According to any one of claims 5 to 5, the master unit is provided with voltage detection means for detecting a voltage change of the two-wire type signal line, and a change from the voltage detected by the voltage detection means causes a call from the intercom subunit. And the response of the sub-base unit to this call.

According to a seventh aspect of the present invention, in the sixth aspect, the master unit starts supplying operating power to the intercom subunit when the voltage detecting means determines that the intercom subunit is called.
The transmitted video signal is displayed on the monitor TV. After that, when the response of the sub-base unit is determined, the operation power supply of the intercom subunit is stopped and the monitor TV is stopped to disable the call.

According to an eighth aspect of the present invention, in the sixth aspect, when the voltage detecting means determines that the intercom subunit is called, the master unit starts supplying operating power to the intercom subunit.
When the transmitted video signal is displayed on the monitor TV and then the response of this master unit is detected, the operation power supply of the intercom sub-unit is stopped for a predetermined time, and it is confirmed that the call was answered. Notice.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the sub-master unit has a depolarizing means for matching the polarity of the voltage supplied from the master unit with the polarity of the sub-master unit. Further equipped.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of the internal configuration of a TV intercom system, and FIG. 2 is a diagram showing an outline of the configuration of the TV intercom system. As shown in FIG. 2, the TV intercom system of the present invention includes an intercom sub-master device 3 with a monitor TV, which is connected to the intercom subunit 2 with a camera via a two-wire signal line L, and its sub-master device 3. The intercom master unit 1 with a monitor television connected via a two-wire signal line L is provided. That is, the present invention relates to one base unit 1
In a system consisting of and one intercom subunit 2
It can be configured by additionally connecting (adding) the sub-base unit 3 of one unit.

When there is a call from the child device 2, the parent device 1 will have the child device 2
Since the power supply is started, the video signal captured by the camera of the child device 2 is transmitted to the parent device 1 and the sub parent device 3. When the master unit 1 responds to this, bidirectional audio signal transmission between the slave unit 2 and the master unit 1 becomes possible. At this time, a control signal is sent from the master unit 1 to the sub master unit 3. On the other hand, when the sub-base unit 3 responds, the connection between the sub-unit 2 and the base unit 1 is disconnected, the power supply from the sub-base unit 3 to the sub-unit 2 is started, and the connection between the sub-unit 2 and the sub-base unit 3 is started. Bidirectional audio signal transmission becomes possible.

As described above, in the system of the present invention, it is not necessary to mutually transmit control signals between the parent device 1 and the sub-parent device 3 as in the conventional system (see FIG. 6B), and the parent device 1 Sub-master 3
All that is required is to send a control signal to. Further, as will be described later, since the control signal is transmitted by a simple method, there is no need to provide a control signal transmission / reception circuit similar to the conventional one (see FIG. 8).

In order to operate as described above, the sub-base unit 3 has, as shown in FIG. 1, switching means for switching the connection with the intercom subunit 2 to either the base unit 1 side or the sub-base unit 3 side. As such, a changeover switch SW30 is provided. Changeover switch SW
In the standby state, the intercom slave 2 and the base unit 1 are connected to each other. When a call start operation is performed on the base unit 1, a control signal is transmitted from the base unit 1 to the sub base unit 30. Since it is transmitted, the sub-base unit 3 transitions to the base unit talking state when receiving the control signal. On the other hand, when the call start operation is performed on the sub-base unit 3, the switching unit SW30 disconnects the signal line L to the base unit 1 to connect the intercom subunit 2 and the sub-base unit 3 to enable the call.

The operation for starting a call in the base unit 1 and the sub-base unit 3 includes operation of call buttons B1 and B3 for answering a call from the intercom subunit 2, and a call handset. In the case of the configuration, there is such a hook-off operation. The sub-base unit 3 includes a changeover switch SW30 and a CPU.
30 and a multiplexing circuit 31 for multiplexing a video signal and an audio signal
A power supply circuit 32 for supplying operating power to the slave unit 2, a call circuit 33 having a speaker SP3 and a microphone MI3,
Video circuit 34 for displaying video on monitor TV M3
And a power supply circuit 35 that supplies power to each unit in the sub-base unit 3.
, A voltage detection circuit 36 which is a voltage detection means for detecting a DC voltage change of the two-wire type signal line L, a termination circuit 37, and a call button B operated to respond to a call from the slave unit 2.
3 and a video selector switch SW31 for connecting the slave unit 2 and the video circuit 34 without the termination circuit 37.

In the sub-base unit 3, the call button B3 is
It also has the function of a monitor button to monitor the video / audio on the slave unit 2, and if it is operated in response to a call from the slave unit 2, it will function as a call button to start a call, but when in standby (non- It operates as a monitor button when operated during a call. In this way, unlike the conventional configuration, the sub-base unit 3 serves as a power feeding unit that supplies operating power to the intercom sub unit 2, and the power feeding circuit 32.
Is equipped with. As a result, when the changeover switch SW30 connects the intercom subunit 2 and the sub-base unit 3, the power supply circuit 32 starts to supply the operating power of the intercom subunit 2. Therefore, even if the intercom subunit 2 is separated from the master unit 1 by the changeover switch SW30, the intercom subunit 2 can be supplied with power from the sub master unit 3.

Further, the sub-base unit 3 can discriminate between the call from the intercom subunit 2 and the response of the base unit 1 to the call, based on the change in the voltage detected by the voltage detection circuit 36. The machine 1 includes a CPU 10 and a multiplex circuit 11
A power supply circuit 12 for supplying drive power to the slave unit 2; a call circuit 13 having a speaker SP1 and a microphone MI1;
Video circuit 14 for displaying an image on the monitor TV M1
And a power supply circuit 15 for supplying power to each unit in the base unit 1,
A call detection circuit 16 for detecting a call from the child device 2, a terminating circuit 17, and a call button B1 operated to answer the call from the child device 2 are provided.

As with the sub-base unit 3, the call button B1 of the base unit 1 also has a function of a monitor button for monitoring video / audio on the side of the handset 2. If it is operated in response to the call, it functions as a call button for starting a call, and if it is operated during standby (during no call), it functions as a monitor button. Here, the call detection circuit 16 constitutes a voltage detection means for detecting a voltage change of the two-wire type signal line L, and the change in the detected voltage causes a call from the intercom 2 as well as a call from the intercom 2 to occur. It is possible to determine the response of the sub-base unit 3 to the call.

The slave unit 2 includes a multiplexing circuit 20 and a speaker SP.
2 and a microphone circuit MI2, and a video circuit 22 for processing a video image captured by a camera circuit 23.
And a call signal generation circuit 24 that generates a call signal by detecting an operation of the call button B2, and a power receiving circuit 25 that receives power supply from the master unit 1 or the sub master unit 3. When the call button B2 is operated in the slave unit 2, the call signal generation circuit 24 generates a call signal and transmits the call signal through the two-wire signal line L.
This ringing signal is sent out according to the change of the DC voltage, and the changeover switch SW30 of the sub-master unit 3 is connected to the a1 side so as to connect the slave unit 2 and the master unit 1 in the standby state. Therefore, when the ringing detection circuit 16 of the base unit 1 detects this ringing signal, a ringing tone is output and the power supply circuit 12 starts supplying operating power to the slave unit 2. At the same time, the voltage detection circuit 36 of the sub-base unit 3 detects a ringing signal, and the sub-base unit 3 also outputs a ringing tone.

Upon receiving power supply from the power receiving circuit 25, the child device 2 drives the camera circuit 23 to transmit the photographed image through the video circuit 22 and the multiplexing circuit 20 through the signal line L. In the master unit 1 and the sub-master unit 3, the video signal transmitted as the baseband signal through the signal line L is
It is displayed on the monitor televisions M1 and M3 by the video circuits 14 and 34.

At this time, the video selector switch S of the sub-master unit 3
W31 is switched from the b1 side to the b2 side, does not connect the terminating circuit 37, and the terminating circuit 17 of the parent device 1 connects the video circuit 34 to the signal line L with high impedance. Become. If the base unit 1 responds by looking at the image displayed on the monitor TV M1 and starting a call with the call button B1, the CPU 10 of the base unit 1 detects this and sends a signal to the sub-base unit 3. Through line L, the supply of operating power from the power supply circuit 12 to the intercom subunit 2 as a control signal is stopped for a predetermined time to notify that the call has been answered. After that, in the base unit 1, the monitor TV M
While looking at 1, the call circuit 13 enables an intercom call with the call circuit 21 of the child device 2.

On the other hand, in the sub base unit 3, the voltage detection circuit 36 detects the notification that the base unit 1 has responded,
When receiving as a control signal, the CPU 30 keeps the changeover switch SW30 on the a1 side, but the video changeover switch S
W31 is switched from the b2 side to the b1 side, and the operation of the monitor TV M3 is stopped to enter the master phone call state (the sub-master phone call disabled state). Specifically, the fact that the base unit 1 is in a call is displayed by a lamp (not shown) or the like, the video circuit 34 is turned off to stop the video display displayed on the monitor TV M3, and the call circuit 33 is used. Prohibit calls.

When the intercom call between the handset 2 and the base unit 1 is completed, the base unit 1 stops the supply of operating power from the power supply circuit 12, and the voltage level becomes the operating state level (for example, 1).
Since the voltage changes from 5V) to the standby state level (for example, 6V), the voltage detection circuit 36 of the sub-base unit 3 detects this and returns the base unit communication state to the standby state. On the contrary, when the sub-base unit 3 responds to the call from the intercom subunit 2 by operating the call button B3 to start a call, the CPU 30 of the sub-base unit 3 which detects the response switches the call. The switch SW30 disconnects the signal line L between the slave unit 2 and the master unit 1,
The child device 2 and the sub parent device 3 are connected. That is, the changeover switch SW30 is switched from the a1 side to the a2 side. Then,
The power supply circuit 32 starts supplying operating power to the slave unit 2. Further, instead of the termination circuit 17 of the master device 1, the termination circuit 37 is connected to the signal line L. afterwards,
In the sub-base unit 3, the call circuit 33 enables an intercom call with the call circuit 21 of the slave unit 2 while watching the monitor TV M3.

In the one base unit 1, the call detection circuit 16 is
It is detected that the voltage level (eg, 6V) in the standby state has changed to the level (eg, 10V) in the open state, and the sub-base unit 3
When the response (switching of the changeover switch SW30) is determined, the power supply circuit 12 stops the supply of operating power to the intercom subunit 2, and the monitor TV M1 stops operating to deactivate the sub-master unit call state (main unit call disabled). State). In particular,
The fact that the sub-base unit 3 is in a call is displayed by a lamp (not shown) or the like, the video circuit 14 is turned off to stop the video image displayed on the monitor TV M1, and the call by the call circuit 13 is prohibited. .

At this time, since the master unit 1 is disconnected from the signal line L by the changeover switch SW30 of the sub master unit 3, the video signal and the call signal are not transmitted to the master unit 1. It is not necessary to actively prohibit video display or call, but video mute or call mute should be muted in order to avoid a situation where the monitor TV M1 is operating but no video signal comes in, or noise is output from the speaker SP1. To do.

When the intercom call between the handset 2 and the sub-base unit 3 is completed, the changeover switch SW30 switches the a2 side to the a1 side.
Since it is switched to the side, the call detection circuit 16 of the base unit 1 changes the voltage level (for example, from 10V (open voltage) to 6V).
Is detected, the sub-main unit communication state is returned to the standby state, and the voltage level of the signal line L becomes the standby level (for example, 6V). In the sub-base unit 3, after switching the changeover switch SW30, the power supply from the power feeding circuit 32 is stopped.

When the call button B1 of the base unit 1 is operated in a standby state where there is no call from the base unit 2, the power supply circuit 12 of the base unit 1 starts power supply to execute the monitor function. Video from the monitor 2 side
, Or the sound on the slave unit 2 side is output from the speaker SP1 for monitoring. At this time, the sound of the master unit 1 side is the slave unit 2
The microphone MI1 is muted so as not to leak on the side.

In the sub-base unit 3, the voltage detecting circuit 36 detects that the voltage level has changed from the standby state level (for example, 6V) to the operating state level (for example, 15V), and receives this as a control signal. Then, CPU30
However, while maintaining the changeover switch SW30 on the a1 side and the video changeover switch SW31 on the b1 side, the sub base unit 3 is set to the base unit call state (sub base unit call disabled state). Specifically, the fact that the base unit 1 is being monitored is displayed by a lamp (not shown) or the like, and the call by the call circuit 33 is prohibited. At this time, it is desirable that the sub-base unit 3 also prohibits video / audio monitoring by operating the call button B3. It should be noted that the lamp or the like indicating that the monitor is in progress may be shared with the lamp or the like indicating that the parent device 1 is talking.

When the monitoring is completed, the voltage detecting circuit 36 of the sub-master 3 detects that the voltage level of the signal line L has changed from the operating level (for example, 15V) to the standby level (for example, 6V). Then, the state where the sub-base unit cannot talk is returned to the standby state. On the other hand, when the call button B3 is operated in the standby state in the sub-base unit 3, the changeover switch SW30 is switched to the a2 side and the video selection switch SW31 is set to the b2 side in order to execute the monitor function, and the signal line to the main unit 1 is switched. L is disconnected, power supply is started from the power supply circuit 32, and video and audio from the slave unit 2 side are monitored. At this time, the microphone MI3 is muted so that the sound on the sub-base unit 3 side does not leak on the slave unit 2 side.

In the base unit 1, the call detection circuit 16
The voltage level of the signal line L is the level in the standby state (for example, 6
When it is detected that the level has changed from V) to the open state level (for example, 10 V), the CPU 10 of the base unit 1 sets the sub base unit call state (base unit call disabled state). Specifically, a lamp (not shown) indicates that the sub-base unit 3 is being monitored,
A call by the call circuit 13 is prohibited. At this time, base unit 1
Since it is separated from the signal line L, it is not necessary to actively prohibit it, but it is desirable to also prohibit the video / audio monitor by operating the call button B1 in the standby state. In addition,
The lamp indicating that the monitor is in progress may be shared with the lamp indicating that the sub-base station 3 is in a call.

When the monitor ends, the sub-master 3 returns the changeover switch SW30 from the a2 side to the a1 side.
The call detection circuit 16 detects the voltage level supplied by the power feeding circuit 32 of the sub-base unit 3 and returns the sub-base unit communication state to the standby state. After that, the power supply circuit 32 of the sub-base unit 3 stops the power supply. FIG. 3 shows the operation of the above TV intercom system. Here, a case is shown in which the parent device 1 responds to the call from the child device 2. When the call button B2 is operated on the child device 2, at the point (A) of FIG.
Since the voltage level changes from the standby state level (for example, 6V) to the calling state level (for example, 3V), this is set as the master unit 1
Is detected by the call detection circuit 16 and the power supply circuit 12 starts power supply. At this time, the voltage level of the signal line L becomes an operating level (for example, 15 V), but when the call button B1 of the base unit 1 is operated, the power supply from the power feeding circuit 12 is stopped for a predetermined time t. It shall be a control signal transmission. Then, the voltage detection circuit 36 of the sub-base unit 3 detects this, and thus it can be determined that the base unit 1 has responded. In the present invention, the base unit 1 is constructed by such a simple method.
Can transmit a control signal from the sub master unit 3.

Next, another configuration of the TV intercom system is shown in a block diagram in FIG. The illustrated configuration is the same as the configuration of FIG. 1, but as a depolarizing means for matching the polarity of the voltage supplied from the master unit 1 to the sub master unit 3 with the polarity of the sub master unit 3. The only difference is that a depolarizing circuit 38 is provided. The depolarizing circuit 38 has a configuration as shown in FIG. 5, and at the point (B) on the base unit 1 side (see FIG. 4), for example, of the signal line L consisting of two lines, the B1 side is the positive pole. If so, the LED of the photo coupler PC
No current flows through. Therefore, the relay R is not excited,
Since the contact point remains on the r1 side, the C1 side of the (C) point (see FIG. 4) on the slave unit 2 side becomes a positive pole, and the polarities match.
However, at point (B) on the base unit 1 side, if the B1 side is a negative pole, current flows through the LED of the photocoupler PC, the transistor is turned on, the relay R is excited, and the contact is from the r1 side to the r2 side. , The polarity is reversed,
The polarities of the master device 1 and the sub-master device 3 match.

As described above, according to the present invention, the connection between the base unit 1 and the sub-base unit 3 can be automatically made non-polar, so that wiring can be performed without worrying about the polarity at the time of construction.
The master unit 1 having the above-described configuration can also be applied to a configuration without the sub master unit 3, that is, a one-to-one system in which the master unit 1 and the intercom subunit 2 are connected via the two-wire signal line L.

[0044]

As can be understood from the above description, in the television interphone system according to the first aspect of the present invention, in the sub-master unit of the system including the intercom slave unit, the master unit and the sub-master unit. , When the master unit starts a call with the slave unit, the control signal from the master unit maintains the connection with the intercom slave unit on the master unit side, and the sub master unit talks with the slave unit. Since the connection with the intercom subunit is switched to the sub-master unit side when starting, it is not necessary to provide a control signal receiving circuit in the master unit and a control signal transmitting circuit in the sub-master unit. Therefore, each of the main unit and the sub-main unit can suppress an increase in manufacturing cost as compared with the main unit of the system including only the slave unit and the main unit.

In the second aspect, the sub-base unit starts supplying the operating power to the intercom sub-unit when the intercom sub-unit is connected. Therefore, even if the sub-unit and the base unit are disconnected, Intercom calls can be made in the slave unit. In the third aspect, the sub-base unit detects the voltage change of the two-wire type signal line and determines the call from the intercom subunit and the response of the base unit to the call, so that the control is performed with a simple configuration. Signal can be detected. According to claim 4, when the base unit answers after the call from the intercom slave unit, the monitor display is stopped and the call is disabled. Therefore, it is understood that the base unit and the base unit are in a call. Further, in claim 5, when the sub-base unit responds, the connection of the intercom subunit is switched to the side of the sub-base unit, so that it is understood that the main-unit side cannot make a call.

In the sixth aspect, the master unit detects a voltage change of the two-wire type signal line and discriminates the call from the intercom subunit and the response of the sub-master unit to this call. Thus, it is possible to determine that the sub-base unit is in a call. Claim 7
Then, when the sub-base unit answers after the call from the intercom sub-unit, the monitor display is stopped and the call is disabled, so that it is understood that the sub-unit and the sub-base unit are in a call. Further, in claim 8, when the base unit answers, the supply of the operating power of the intercom subunit is stopped for a predetermined time, and the fact that the call is answered can be notified with a simple configuration.

According to the ninth aspect, the sub-master unit automatically matches the polarity of the voltage supplied from the master unit with the polarity of the sub-base unit. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a configuration of a television intercom system of the present invention.

FIG. 2 is a diagram schematically showing a configuration of a television intercom system of the present invention.

FIG. 3 is a diagram showing an example of the operation of the television intercom system of the present invention.

FIG. 4 is a block diagram showing another example of the configuration of the television intercom system of the present invention.

FIG. 5 is a diagram showing an example of a configuration of a depolarizing circuit.

FIG. 6 is a diagram showing a configuration of a conventional TV intercom system.

FIG. 7 is a block diagram showing an example of a configuration of the conventional TV intercom system shown in FIG.

FIG. 8 is a block diagram showing an example of a configuration of the conventional TV intercom system shown in FIG. 6 (b).

[Explanation of symbols]

1 Intercom base unit with monitor TV 12 power supply circuit 16 Call detection circuit 2 Doorphone subunit with camera Intercom sub-master with 3 monitor TV SW30 selector switch 32 power supply circuit 36 Voltage detection circuit 37 Termination circuit 38 Depolarizing circuit

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04M 9/00-9/10

Claims (9)

(57) [Claims] 1. An intercom sub-master unit with a monitor TV connected to an intercom subunit with a camera via a two-wire signal line, and a monitor TV connected to the sub-master unit via a two-wire signal line. A television intercom system configured to include an intercom base unit, and a switching means for connecting the intercom slave unit and the base unit to each other is provided in the sub base unit during standby, and a call is started at the base unit. When the operation is performed, the base unit transmits a control signal to the sub-base unit, and when the sub-base unit receives the control signal, the base unit makes a transition to the base unit talking state, and the sub-base unit starts a call operation. Then, the television interphone system is characterized in that the switching means disconnects the signal line to the master unit to connect the intercom slave unit and the sub-master unit to enable communication. 2. The sub-base unit further comprises power feeding means for supplying operating power to the intercom sub-unit, and when the switching means connects the intercom sub-unit,
2. The television intercom system according to claim 1, wherein the power supply means starts supplying operating power to the intercom subunit. 3. The sub-base unit further comprises voltage detecting means for detecting a voltage change of the two-wire type signal line, and a change in the voltage detected by the voltage detecting means causes a change from the intercom subunit. The television intercom system according to claim 1 or 2, wherein a call and a response of the master unit to the call are determined. 4. The sub-base unit displays a video signal transmitted from the intercom slave unit on a monitor television when the voltage detecting means determines that the intercom slave unit is calling, and then the sub-base unit operates. 4. The television intercom system according to claim 3, wherein when the response is determined, the operation of the monitor television is stopped so that the telephone call is disabled. 5. The sub-base unit displays a video signal transmitted from the intercom sub-unit on a monitor television when the voltage detection means determines that the intercom sub-unit is called, and then the sub-base unit. 4. The television intercom system according to claim 3, wherein when the response is detected, the switching means switches the connection of the intercom subunit to the sub-master unit side. 6. The base unit is provided with a voltage detecting means for detecting a voltage change of the two-wire type signal line, and a change from the voltage detected by the voltage detecting means causes a call from the intercom subunit. The television intercom system according to any one of claims 1 to 5, characterized in that the response of the sub-base station to this call is determined. 7. The base unit starts supplying operating power to the intercom subunit when the voltage detecting means determines that the intercom subunit is called, and sends the transmitted video signal to the monitor television. 7. When the image is displayed and then the response of the sub-base unit is determined, the supply of operating power to the intercom subunit is stopped, the operation of the monitor television is stopped, and the call disabled state is set. TV intercom system described. 8. The master unit starts supplying operating power to the intercom subunit when the voltage detecting means determines that the intercom subunit is calling, and transmits the transmitted video signal to the monitor television. 7. The image is displayed, and thereafter, when the response of the master unit is detected, the supply of the operating power of the intercom subunit is stopped for a predetermined period of time to notify that the call has been answered. TV intercom system described in. 9. The sub-master unit further comprises depolarizing means for matching the polarity of the voltage supplied from the master unit with the polarity of the sub-master unit. The TV intercom system according to claim 8.