JP2000175181A - Video signal branching method and interphone system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interphone system where the impedance is matched in the case of branching a video signal and attenuation in the video signal can be reduced. SOLUTION: The interphone system is provided with a transmission line 1 to transmit a video signal photographed by a camera 2 and with a plurality of video adaptors 4 each connected to each monitor 3 and to branch the video signal transmitted on the transmission line 1 to the monitor 3. The video adaptor 4 is inserted in the transmission line 1 and connects the transmission line 1 at the side of the camera 2 and the transmission line 1 only to the succeeding video adaptor 4 usually and connects the transmission line 1 at the side of the camera 2 and only the monitor 3 in the case of branching the video signal transmitted through the transmission line 1 to the monitor 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intercom system used in an apartment house or the like, and more particularly to a branch of a video signal.

[0002]

2. Description of the Related Art Conventionally, as a branch of a video signal for monitor display on an intercom side in an intercom system or the like, a transmission line is simply drawn from an image signal transmission line as a branch line to an interphone or the like and branched. Since impedance matching cannot be achieved in the line and signal reflection occurs, a branching device using a transformer or the like is installed at the point of entry to the intercom side,
In general, a video signal is branched while matching impedance.

[0003]

In the case of a video signal branching by a conventional branching device using a transformer or the like, a signal is always attenuated at a branching portion. Since the transmission of the video signal becomes impossible, there is a problem that many branch points are restricted. That is, in an intercom system or the like, 1
The number of monitor-equipped interphones that can be connected to the transmission line of the video signal of a book has been limited.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a video signal branching device capable of branching a video signal with no restriction at a branching point without impairing impedance matching. It is an object to provide a method and an intercom system.

[0005]

According to a first aspect of the present invention, there is provided a video signal branching method including a collective entrance intercom provided with a camera, and a monitor provided in each dwelling unit for displaying a video taken by the camera. In a video signal branching method in an intercom system including a plurality of intercoms, a video signal captured by a camera is transmitted to a transmission line, and the video signal is branched to a monitor on the transmission line. The connection of the subsequent transmission lines is cut off and branched.

[0006] An intercom system according to a second aspect of the present invention includes a collective entrance intercom provided with a camera, and a plurality of intercoms provided in each dwelling unit and provided with a monitor for displaying an image captured by the camera. In the intercom system, a transmission line for transmitting a video signal captured by a camera, and a plurality of video adapters connected to each of the monitors and branching the video signal transmitting the transmission line to the monitor, wherein the video adapter is Normally, only the transmission line on the camera side and the transmission line to the next video adapter are connected, and when the video signal transmitted on the transmission line is branched to the monitor, Only the transmission line and the monitor are connected.

[0007]

FIG. 1 is a block diagram showing a configuration of a video signal transmission apparatus to which a video signal branching method according to an embodiment of the present invention is applied. In the figure, 1 is a transmission line for transmitting a video signal, 2 is a camera for transmitting a video signal, 3 is a monitor for receiving a video signal transmitted from the camera 2 and displaying an image thereof. Are provided. Reference numeral 4 denotes a video adapter which is inserted into the transmission line 1 and branches the video signal to the monitor 3.

Next, the operation of this embodiment will be described. First, the video signal photographed by the camera 2 is transmitted through the transmission line 1
And transmitted on the transmission line 1. When displaying an image captured by the camera 2 on one of the monitors 3, the video adapter 4 connected to the monitor is operated to connect the transmission line 1 to the monitor 3. Then, the connection with the transmission line 1 after the video adapter 4 is physically disconnected.

In this embodiment, when an image is displayed on a certain monitor 3, the camera 2 and the monitor 3 are directly connected by the transmission line 1, and there is no signal attenuation for branching the image signal. Even if a plurality of monitors are connected via the video adapter 4 on the way, the signal level of the video signal does not decrease, so that the limitation on the number of monitors to be installed can be eliminated. In addition, when an image is displayed on a certain monitor 3, since there is no branch to the other, impedance matching is achieved and no reflection of the image signal occurs, so that the image signal is transmitted without being deteriorated. Becomes possible.

Next, a specific application example of this embodiment will be described. FIG. 2 is a diagram showing a specific application example of this embodiment, and here, for example, shows an application example in an intercom system. In the figure, 10
Is the camera installed in the entrance intercom etc.,
Reference numeral 11 denotes a video control device for controlling video related to the intercom system, 12 denotes a distributor for distributing the video signal, 13 denotes a transmission line for transmitting the video signal, 14 denotes an intercom installed in each dwelling unit, 15 denotes an interphone Monitor 16 is connected to the monitor 15 and the transmission line 13
Is a video adapter for branching the video signal transmitting the video signal to the monitor 15, and 17 is a call control device for controlling the call-related relationship of the intercom system and controlling the video control device 11.

Here, first, the operation of the intercom system according to this embodiment will be described. First, when a visitor operates a collective entrance intercom (not shown) to enter a room number to be visited at the entrance of an apartment house or the like, and then presses a call switch, the room code is transmitted from the collective entrance intercom to the call control device 17. A call signal including a call code is transmitted. And the call control device 17
When a call signal is received from the collective entrance intercom, the communication path between the collective entrance intercom and the target intercom 14 is established so that the collective intercom that transmitted the call signal and the interphone 14 of the room number to be called can communicate with each other.

Further, when the collective entrance intercom is operated, the camera 10 installed in the collective entrance intercom (not shown) is supplied with power from the video control device 11 in accordance with an instruction from the call control device 17, and the The operator shoots an image and sends the image signal to the image control device 11.
Send to Then, the video signal is transmitted to the video control device 11.
Is output to the transmission line 13 and is called, and the called intercom 14 is connected to the monitor 15
The video signal transmitted through the transmission line 13 is branched and the monitor 15 displays the video captured by the camera.

Here, when the video adapter 16 branches the video signal to the monitor 15, the video controller 11
Only the transmission line 13 on the side and the monitor 15 are connected, and the connection between the transmission line 13 on the video control device 11 side and the transmission line 13 to the video adapter 16 of the next dwelling unit is physically disconnected, Conversely, when the video signal is not branched to the monitor 15, the transmission line 13 on the video control device 11 side and the monitor 15
Is physically disconnected, and only the transmission line 13 on the video controller 11 side and the transmission line 13 to the video adapter 16 in the next dwelling unit are connected.

Thus, when the video signal is not branched to the monitor 15, only the transmission line 13 of the video controller 11 and the transmission line 13 to the video adapter 16 of the next dwelling unit are connected. It is possible to minimize the attenuation of the video signal in the video adapter 16, and when the video signal is branched to the monitor 15, only the transmission line 13 and the monitor 15 on the video control device 11 side Is connected, the impedance can be matched even when the video signal is branched to the monitor 15.

Here, a specific configuration of the video adapter 16 will be described. FIG. 3 is a diagram illustrating an example of a specific configuration of the video adapter 16. In the figure, reference numeral 20 denotes a transmission line, and here, a twisted pair line is used. Reference numeral 21 denotes a contact portion of a relay for splitting a video signal transmitted on the transmission line 20. This contact portion is normally connected to the transmission line 20 from the video control device 11 and the video adapter 16 of the next dwelling unit. Is connected to the transmission line 20. Reference numeral 22 denotes a relay unit for splitting a video signal. The relay unit is driven by a circuit in the intercom 14 in the dwelling unit as shown in FIG. 4, for example. The video adapter 16 is controlled according to an instruction from the device 17. Reference numeral 23 denotes a transmission line to a monitor in a dwelling unit, which is connected to the transmission line 20 through the relay contact 21 by driving the relay unit 22.

Next, the operation of the video adapter will be described. First, at the normal time when the image is not displayed on the monitor, the contact portion 21 of the relay is connected to the transmission line 2 on the image control device side.
0 and only the transmission line 20 to the video adapter of the next dwelling unit is connected, and the transmission line 23 to the monitor 15 is connected.
Is physically disconnected.

A circuit in the intercom 14 in the dwelling unit as shown in FIG. 4 turns on the transistors Tr1 and Tr2 by an ON control signal from a control circuit (not shown), for example, and a driving power is applied to the relay unit 22. When the relay section 22 is driven, the contact section 21 of the relay operates,
The transmission line 20 on the video controller 11 side and the monitor 15 in the dwelling unit
And only the transmission line 23 to the monitor 1 is connected.
5 displays an image of a video signal transmitted on the transmission line 20 of the video control device 11. At this time, the video control device 1
The connection between the transmission line 20 from the first side and the transmission line 20 to the video adapter 16 of the next dwelling unit is physically disconnected,
Even if the video signal is branched to the monitor 15, the transmission line is not branched as a branch line in other video adapters.
Impedance matching can be achieved.

Here, there are two transmission lines for transmitting a video signal, and a video adapter 16 for splitting a video signal transmitted on one of the two transmission lines and displaying it on a monitor. A typical configuration will be described. FIG. 5 is a diagram showing an example of a specific configuration of the video adapter 16 connected to two transmission lines for transmitting video. In the figure, 30-
Reference numerals 1 and 30-2 denote transmission lines, each of which uses a twisted pair line. 31-1 and 31-2 are transmission lines 30-1,
This is a contact portion of a relay for branching the video signal transmitting 30-2, which is normally connected to the transmission lines 30-1 and 30-2 from the video controller 11 side and the next dwelling unit. The transmission lines 30-1 and 30-2 to the video adapter 16 are connected. 32-1 and 32-2 are relay units for splitting a video signal. The relay unit includes, for example,
One of them is driven by a circuit in the intercom 14 in the dwelling unit as shown in FIG. 6, and the intercom 14 in the dwelling unit controls the video adapter 16 in accordance with an instruction from the call control device 17. It has become.

FIGS. 5 and 6 show two transmission lines 3.
Relay units 32-1 and 32-2 connected to 0-1 and 30-2
One of the relays is driven by changing the polarity of the DC voltage supplied to the relay.

Next, the operation of the video adapter will be described. First, when the monitor is not displaying an image, the relay contacts 31-1 and 31-2 are both connected to the transmission lines 30-1 and 30-2 on the image controller side and the image adapter of the next dwelling unit. Are connected only to the transmission lines 30-1 and 30-2, and the connection of the transmission line 33 to the monitor 15 is physically disconnected.

Then, a circuit in the intercom 14 in the dwelling unit as shown in FIG.
When an ON signal is output to r1 as an ON control signal and an image selection signal, and the relay unit 32-2 is driven, the contact unit 31-2 of the driven relay operates to operate the relay unit 32-2. 2 is connected to the transmission line 30-2 on the video controller side connected to the monitor 15 in the dwelling unit, and only the transmission line 33 to the monitor 15 in the dwelling unit is connected. The image of the image signal transmitted on the transmission line 30-2 is displayed. At this time, the connection between the transmission line 30-2 from the video controller 11 side to which the driven relay is connected and the transmission line 30-2 to the video adapter 16 of the next dwelling unit is physically disconnected. Even if the video signal is branched to the monitor 15, since the transmission line is not branched as a branch line in another video adapter, impedance matching can be achieved.

In this embodiment, an example has been described in which the video adapter is constituted by a relay. However, when the video signal transmitted on the transmission line is branched, the transmission line is connected to the video adapter of the next dwelling unit. Any device that physically disconnects the connection may be used. Further, in this embodiment, one or two video signal transmission lines have been described, but the present invention is also applicable to an intercom system using two or more transmission lines.

[0023]

As described above, according to the present invention, normally, only the transmission line on the camera side and the transmission line to the next video adapter are connected by the video adapter inserted into the transmission line,
When the video signal transmitted on the transmission line is branched to the monitor, only the transmission line on the camera side and the monitor are connected.When the video signal is branched to the monitor, the video signal is branched. The video signal is not transmitted to the transmission line to the video adapter after the video adapter that is connected, and impedance matching can be performed. In normal times, only the transmission line on the camera side and the transmission line to the next video adapter are used. Is connected, there is an effect that the attenuation of the video signal in the video adapter can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a video signal transmission device to which a video signal branching method according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a specific application example of the embodiment.

FIG. 3 is a diagram showing an example of a specific configuration of a video adapter 16;

FIG. 4 is a diagram showing a circuit example in an intercom that operates the video adapter 16 shown in FIG.

FIG. 5 is a diagram showing an example of a specific configuration of a video adapter 16 connected to two transmission lines for transmitting video.

FIG. 6 is a diagram showing a circuit example in an intercom that operates the video adapter 16 shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transmission line 2 camera 3 monitor 4 video adapter 10 camera 11 video control device 12 distributor 13 transmission line 14 intercom 15 monitor 16 video adapter 17 communication control device 20 transmission line 21 relay contact part 22 relay part 30 transmission line 31 relay Contact part 32-1, 32-2 Relay part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takashi Toda 4-7-3 Kudanminami, Chiyoda-ku, Tokyo Nomi Disaster Prevention Co., Ltd. F term (reference) 5C054 CH08 EA03 HA22 5K038 AA07 CC12 DD15 DD23 FF04

Claims (2)

[Claims] 1. A video signal branching method in an intercom system including a collective entrance intercom provided with a camera, and a plurality of intercoms provided in each dwelling unit and provided with monitors for displaying images taken by the cameras. In, transmitting a video signal captured by the camera to a transmission line,
When the video signal is branched to the monitor on the transmission line, a connection of a transmission line after a branch point of the video signal is disconnected and the video signal is branched. 2. An intercom system comprising: a collective entrance intercom provided with a camera; and a plurality of intercoms provided in each dwelling unit and provided with a monitor for displaying an image photographed by the camera. A transmission line for transmitting a captured video signal; anda plurality of video adapters connected to each of the monitors and branching the video signal transmitting on the transmission line to the monitor. Normally, only the camera-side transmission line and the transmission line to the next video adapter are connected, and when the video signal transmitted on the transmission line is branched to the monitor, An intercom system, wherein only a transmission line on a camera side and the monitor are connected.