JPH09168133A - Communication terminal equipment and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect together many communication terminal equipments via a simple wiring and also to transmit the control signal of an optional communication terminal as necessary to perform communication with a host system. SOLUTION: In a 1st mode (switch 40 connected to contact (a) side), the control signal that is separated from the multiple signal that is sent from the next stage via a multiple signal separation part 32 is inputted to a control signal multiplexing part 38 together with the control signal of a communication terminal equipment 3 through the decoding and encoding processes. These input signals are multiplexed in a vertical blanking period of the video signal inputted from a video input device 45 and then outputted to the preceding stage. In a 2nd mode (switch 40 connected to contact (b) side), the multiple signal sent from the next stage is directly outputted to the preceding stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal device that collects information from a video input device or an audio input device and is centrally controlled by a host system, and a communication system composed of the communication terminal device and the host system. .

[0002]

2. Description of the Related Art Recently, in a relatively small area, a communication system for acquiring video and audio signals at a plurality of points without using a public line and for controlling the acquisition of these signals has become widespread. ing. In this system, analog signals are often handled as they are, because communication is performed in a relatively short distance like a simple video conference system and a surveillance system.

A conventional communication terminal device and communication system will be briefly described below with reference to FIG.

As shown in FIG. 1, control devices 102, 103 and 104 as communication terminal devices are provided with video input devices 105, 107 and 108 and an audio input device 10, respectively.
6, 108, 110 are connected to each control device 102, 1
03 and 104 are individually connected to the exchange 101. The central controller 111 as the host system is the exchange 1
01 is used to obtain a video / audio signal from each of the control devices 102, 103, 104, and the video output device 113 reproduces a video and the audio output device 112 reproduces a sound.

The central control unit 111 obtains a video / audio signal at a place where information is desired to be obtained by switching and selecting a control unit of a communication destination with the exchange 101.

As described above, in the conventional communication terminal device / communication system, the video / audio signals are individually acquired from each control device under the centralized control of the host system such as the central control device 111. ing.

[0007]

However, in the above-mentioned conventional communication system, the system becomes larger as the number of points where the video / audio signals are desired to be increased, and all of the plurality of communication terminal devices are individually connected to the host system. Therefore, there is a problem that wiring becomes difficult.

Further, since each communication terminal device is controlled mainly by the host system and communication can be performed only at the timing of the host system side, for example, while one communication terminal device is communicating with the host system, Another communication terminal device has a problem that it is almost impossible to arbitrarily send a control signal such as a communication request to the host system.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object thereof is to connect a large number of communication terminal devices with easy wiring and to send a control signal of any communication terminal device at any time. An object of the present invention is to provide a communication terminal device and a communication system capable of communicating with a host system while transmitting.

[0010]

In order to achieve the above object, a communication terminal device according to claim 1 of the present invention is a communication terminal device for inputting a video signal and transmitting the video signal to a host system. From a connection means for cascade-connecting communication terminal devices, a multiplex output means for outputting a multiplex signal in which a control signal is multiplexed with the video signal to be transmitted, and a multiplex signal input from another cascade-connected communication terminal device Demultiplexing means for demultiplexing the control signal, wherein the multiplex output means, when the communication terminal device outputs the multiplex signal to the host system, inputs from the other communication terminal device separated into the multiplex signal. It is characterized in that it includes a control signal to be controlled.

In order to achieve the same object, the communication terminal device according to a second aspect of the present invention is the configuration according to the first aspect, wherein the multiplexing by the multiplex output means performs the vertical blanking period of the input video signal. And at least one of the effective periods.

To achieve the same object, in a communication system according to claim 3 of the present invention, a plurality of communication terminal devices according to claim 1 or 2 are cascade-connected to a host system, and the host system outputs the output. It is characterized in that each of the communication terminal devices is controlled based on a control signal included in the multiplex signal.

In order to achieve the same object, in a communication system according to a fourth aspect of the present invention, each of the communication terminal devices includes a voice signal input means for inputting a voice signal, and the multiple output means receives the input. An audio signal is included in the output multiplex signal.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an overall configuration of a communication system including a communication terminal device according to an embodiment of the present invention.

In this system, n terminal devices are cascade-connected, and the first communication terminal device 2 to the n-th communication terminal device 4 are connected in cascade.

Cascade connection means that a plurality of communication terminal devices are connected in cascade so that the output of one communication terminal device becomes the input of the communication device that follows. For example, the output of the latter stage of the communication terminal device 3 is connected so as to be the input of the communication terminal device 3, and the output of the communication terminal device 3 is connected so as to be the input of the communication terminal device 2.

With the first communication terminal device 2 connected in cascade as the frontmost communication terminal device and the communication terminal device 4 as the last stage, hereinafter, communication closer to the communication terminal device 2 with respect to an arbitrary communication terminal device will be described. The terminal device is referred to as “first stage”, and the communication terminal device closer to the communication terminal device 4 is referred to as “second stage”.

Video input devices 5, 6, 7 and audio input devices 8, 9, 10 are connected to the respective communication terminal devices 2, 3, 4 so that the respective communication terminal devices 2, 3, 4 can be connected. A video signal and an audio signal at each location are acquired.

The communication terminal device 2 at the frontmost stage is connected to the host system 1, and the host system 1 has a "previous stage" relationship with the communication terminal device 2.

Between the host system 1 and the communication terminal device 2, and between the communication terminal devices 2, 3 and 4, the control signal is multiplexed during the vertical blanking period in the video signal. Bidirectional communication is performed using a multiplexed signal in which a voice signal FM-modulated to 5 MHz is further added.

As will be described later, the host system 1 centrally controls all the communication terminal devices based on the multiplexed signal received from the communication terminal device 2, and also each communication terminal device 2, 2.
The video signal and the audio signal obtained from 3 and 4 are reproduced by the video output device 11 and the audio output device 12.

FIG. 2 is a block diagram showing the configuration of the host system 1.

In the figure, 26 is a microprocessor (MP
U) and controls the entire host system 1.

The control signal is separated from the multiplexed signal input from the communication terminal device 2 by the control separation unit 21. The separated control signal is decoded by being decoded by the control signal decoding unit 22, and the microprocessor 26
Is input to

On the other hand, the video / audio separation unit 25 separates the video / audio signal from the multiplexed signal left after the control signal is separated.

The video signal separated here is output to the video output device 11, while the audio signal is the audio signal device 12.
Is output to Further, the multiplexed signal obtained by separating the video / audio signals by the video / audio separation unit 25 is input to the microprocessor 26.

A control signal from the host system 1 to each communication terminal device is transmitted from the microprocessor 26. The control signal is encoded by the control signal encoding unit 23, multiplexed by the control signal multiplexing unit 24, and transmitted to the communication terminal device 2.

The host system 1 constantly receives and decodes the multiplexed signal from the communication terminal device 2 and identifies the communication terminal device which is the source of the control signal. That is, it is possible to always receive information as to which communication terminal device is transmitting what control signal. Then, processing according to the control signal is performed.

FIG. 3 is a block diagram of the communication terminal device according to the present embodiment. Here, the communication terminal device 3 of FIG. 2 will be described as an example.

The communication terminal device 3 is entirely controlled by a microprocessor (MPU) 41. The video input device 45 connected to the communication terminal device 3 is controlled by communication with the microprocessor 41. This communication is performed by RS-232C, for example.

In the communication terminal device 3, the signal flow differs between the case where the signal is transmitted from the rear stage to the front stage and the case where the signal is received from the front stage to the rear stage.

First, the case where a signal is transmitted from the latter stage to the former stage will be described.

The switch 40 is in the first mode when it is on the contact a side and in the second mode when it is on the contact b side.

The first mode is a mode selected when a video / audio signal is desired in the communication terminal device 3, and in this mode, the control signal and the video / audio signal are transmitted to the preceding stage.

The second mode is a mode selected when the video / audio signal in the communication terminal device 3 is not desired, and in this mode, the multiplexed signal is transmitted from the latter stage to the front stage as it is, and the communication terminal device 3 concerned. The video and audio signals of are not transmitted.

The communication terminal device for which the first mode is selected is, in principle, one of the plurality of communication terminal devices, and the other communication terminal devices are set to the second mode. From the latter stage, the communication terminal device 3 receives a multiplexed signal including a video signal (base band), an audio signal (FM multiplexing) and a control signal.

In the first mode, the control signal separation unit 32 separates the control signal from the multiplexed signal received from the subsequent stage.

The control signal separated here is decoded by the control signal decoding unit 34, that is, decoded, and input to the microprocessor 41.

The control signal input to the microprocessor 41 is encoded by the control signal encoding unit 36 and input to the control signal multiplexing unit 38.

On the other hand, the microprocessor 41 generates a control signal for the communication terminal device 3 itself, and this signal is also input to the control signal multiplexing unit 38 via the control signal encoding unit 36. If the control signal is, for example, a signal for notifying the host system 1 of the image information of the image input device 45, the image input device 45 → RS-232C → microprocessor 41 → control signal encoding unit 36 → It is input through a path called the control signal multiplexing unit 38.

A video signal is directly input from the video input device 45 to the control signal multiplexer 38. Then, during the vertical blanking period of the video signal, the control signal multiplexing unit 38 multiplexes the input signal relating to the control signal from the latter stage and the input signal relating to the control signal issued by the microprocessor 41.

The multiplexing on the video signal may be performed not only during the vertical blanking period but also during the effective period. Even if the picture is not displayed, there is no problem even if this is done.

On the other hand, from the voice input device 46 connected to the communication terminal device 3, a voice signal is sent to the matrix circuit (mat).
rix) 42, and after the conversion processing of the stereo audio signal is performed, the FM modulator (FMMOD) 43 F
M modulation is performed.

Then, the audio signal FM-modulated by the FM modulator 43 is added to the multiplexed signal output from the control signal multiplexer 38 by the adder 44, and the added multiplexed signal is passed through the switch 40 to the preceding stage. , That is, the communication terminal device 2
Sent to.

On the other hand, the control signal separation unit 32 separates the control signals, and the remaining multiple signals such as video signals are switched by the switch 4
When 0 becomes the contact b, that is, when the mode becomes the second mode, it is transmitted to the preceding stage.

Next, the case where a signal is transmitted from the former stage to the latter stage will be described.

The switch 39 is used to switch on / off of signal transmission, and when it is off, the signal is not transmitted to the subsequent stage at all and is normally in the on state.

The multiplex signal received from the front stage, that is, the communication terminal device 2 is composed of a video signal, an audio signal and a control signal, and the control signal includes a control signal for the communication terminal device 3 (hereinafter, referred to as “the relevant signal”). "Control signal for device"), and a control signal for a communication terminal device at a later stage.

The control signal separation unit 31 separates the control signal for the device from the multiplexed signal received from the preceding stage.
The separated control signal is decoded by the control signal decoding unit 33 and input to the microprocessor 41.

The control signal input to this microprocessor is coded by the control signal coding unit 35 and input to the control signal multiplexing unit 37.

On the other hand, the control signal from the communication terminal device 3 itself to the communication terminal device at the subsequent stage is issued from the microprocessor 41, and similarly input to the control signal multiplexing unit 37 via the control signal encoding unit 35.

On the other hand, the control signal demultiplexing unit 31 demultiplexes the device control signal and leaves the multiplexed signal directly input to the control signal multiplexing unit 37.

Then, to this directly input multiplex signal,
The input signal related to the device control signal and the input signal related to the control signal transmitted from the microprocessor 41 are multiplexed, and the multiplexed multiplexed signal is transmitted to the subsequent stage via the switch 39.

According to this communication terminal device, in the first mode, while transmitting the video / audio signal sampled by itself to the host system 1, the control signal from the latter stage is multiplexed with the control signal of the former stage and the former stage and It can be sent to the host system 1. On the other hand, in the second mode, all multiplexed signals including video / audio signals from the latter stage can be transmitted to the former stage and the host system 1.

As a result, even when another communication terminal device connected in cascade is communicating with the host system 1, the control signal such as a communication request is transmitted to the front stage or the host system in addition to the rear stage and its own video / audio signals. 1 can be sent at any time.

Therefore, according to the present communication system constructed by cascade-connecting such communication terminal devices, even if any of the cascade-connected communication terminal devices is communicating with the host system 1, A control signal such as a communication request of an arbitrary communication terminal device can be transmitted to the preceding stage or the host system 1 at any time.

Furthermore, in constructing this communication system,
It is easy to wire each communication terminal device.

Further, since the control signal is multiplexed in at least one of the vertical blanking period and the effective period in the video signal, it is not necessary to separately provide a transmission line, which contributes to simplification of wiring. Further, it is possible to avoid the problem of waste of frequency band due to multiplexing in the frequency domain of video / audio signals.

In this embodiment, the communication terminal device 3
In the above, although there is a slight difference in the signal flow from the front stage to the rear stage and from the rear stage to the front stage, the same method as the signal transmission method from the rear stage to the front stage can be You may use it.

[0061]

As described above, according to the first aspect of the present invention,
According to the communication terminal device of the present invention, the communication terminal devices of the same type are cascade-connected, the multiplexed signal in which the control signal is multiplexed with the video signal to be transmitted is output, and the multiplexed signal is input from another cascade-connected communication terminal device. When the control signal is separated from the multiplex signal and the communication terminal device outputs the multiplex signal to the host system, the multiplex signal includes the control signal input from the other communication terminal device. A large number of communication terminal devices can be connected by easy wiring, and a control signal of any communication terminal device can be transmitted to the host system side at any time regardless of whether the communication terminal device is in communication.

According to the communication terminal device of the second aspect of the present invention, since the multiplexing by the multiplex output means is performed in at least one of the vertical blanking period and the effective period of the input video signal, The frequency band of a signal or a voice signal can be multiplexed without wasting, and a separate transmission line is not required, and wiring can be facilitated.

According to the communication system of claim 3 of the present invention, a plurality of cascade-connected communication terminal devices are controlled based on the control signal included in the output multiplex signal. The communication terminal device can be connected by easy wiring, and a control signal of an arbitrary communication terminal device can be transmitted to the host system side at any time regardless of whether another connected communication terminal device is in communication.

According to the communication system of claim 4 of the present invention, since the input voice signal is included in the output multiplex signal, a large number of communication terminal devices can be connected by easy wiring and can be connected. The voice signal of any communication terminal device can be transmitted to the host system side at any time regardless of whether another communication terminal device is communicating.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a communication system including a communication terminal device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a host system in the embodiment.

FIG. 3 is a configuration diagram of a communication terminal device according to the present embodiment.

FIG. 4 is an overall configuration diagram of a conventional communication terminal device and communication system.

[Explanation of symbols]

 1 Host System 3 Communication Terminal Device 26 Microprocessor 31 Control Signal Separation Unit 32 Control Signal Separation Unit 33 Control Signal Decoding Unit 34 Control Signal Decoding Unit 35 Control Signal Encoding Unit 36 Control Signal Encoding Unit 37 Control Signal Multiplexing Unit 38 Control signal multiplexing unit 41 Microprocessor (MPU) 44 Adder 45 Video input device 46 Audio input device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H04N 7/18 H04N 5/91 L

Claims (4)

[Claims] 1. In a communication terminal device for inputting a video signal and transmitting the video signal to a host system, a connecting means for cascade-connecting communication terminal devices of the same kind, and a control signal multiplexed on the video signal to be transmitted. The multiplex output means for outputting the multiplexed signal, and the separation means for separating the control signal from the multiplex signal input from the other cascade-connected communication terminal device. A communication terminal device, wherein when outputting the multiplexed signal to a host system, the multiplexed signal includes a control signal input from the other separated communication terminal device. 2. The communication terminal device according to claim 1, wherein the multiplexing by the multiplex output means is performed in at least one of a vertical blanking period and an effective period of the input video signal. 3. A plurality of communication terminal devices according to claim 1 or 2 are cascade-connected to a host system, and the host system controls each of the communication terminal devices based on a control signal included in the output multiplexed signal. A communication system characterized by performing control of. 4. The communication terminal device comprises an audio signal input means for inputting an audio signal, and the multiplex output means includes the input audio signal in the output multiplex signal. Item 3. The communication system according to Item 3.