JP2741796B2 - Videophone equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video telephone having an improved polling function.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing an outline of a video telephone apparatus. In FIG. 5, (1) is a center machine equipped with a monitor television (2), and (3) is a center machine (1).
Is a terminal connected via a communication line (4), and (5) is a video signal output device connected to a plurality of video signal input terminals (6) provided in the terminal (3). here
The center unit and the terminal are both videophone devices,
The terminal has a video playback device. Center machine and end
The end machines are in a master-slave relationship, so to speak.
By dialing the terminal from the
You can see the video. This type of videophone device
Monitors the unattended terminal side from the center unit
For example, Sun Telephone can be used for the system.
A still image transmission system, color visual phone
The VP1000 is known.

Next, a communication procedure at the time of the polling operation shown in FIG. 6 will be described. The center unit (1) transmits a dial signal, confirms the connection of the line, immediately transmits a control signal requesting polling, and outputs an image signal from the video signal output device (5) connected to the terminal (3). The communication line (4)
The image signal is displayed on the monitor television (2) of the center unit (1). This polling operation is sequentially performed for each video signal input terminal (6) provided in the terminal unit (3). Is repeated.

[0004]

Since polling in a conventional video telephone apparatus is performed as described above,
There is a problem that the polling operation is performed also on the video signal input terminal to which the video signal output device (5) is not connected, and an extra image in which nothing is displayed is polled.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a videophone apparatus that does not poll an extra image in which nothing is displayed.

[0006] As for the polling technique, see, for example, JP-A-59-132256,
And JP-A-59-132.
No. 25 discloses that a terminal control device detects whether or not a terminal is connected when polling a plurality of terminals.

[0007]

A video telephone apparatus according to the present invention has a center unit connected to a terminal having a plurality of video signal input terminals via a communication line, and the center unit is connected to the terminal by the center unit. Sending an image status request to the terminal when performing a logical connection performed after the line connection,
In response to the image status request, information on the presence / absence of video input to the video signal input terminal transmitted from the terminal is received, and the video signal input terminal without video input is designated when polling with the terminal. Polling is performed without performing.

[0008]

[Action] videophone apparatus of this invention, the logical connections center machine Ru performed after the communication line is connected to the terminal, by not polling for a video signal input terminal that is not connected to the video signal output apparatus, Polling time can be reduced.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The overall configuration of the videophone device is the same as the conventional device shown in FIG. FIG. 1 is a block diagram showing the configuration of a terminal (3) applied to this device. In FIG. 1, (31) is a switch for sequentially switching a plurality of video signal input terminals (6) , and (32) is a switch. An image control signal circuit for supplying a control signal to the switch (31) and for inputting a video signal input to the video signal input terminal (6) via the switch (31); (33) an image control signal circuit (32) Is a CPU that supplies a control signal to and inputs information (data) from the image control signal circuit.

Next, a communication procedure at the time of polling operation shown in FIGS. 2 and 3 will be described with reference to FIGS. First, the center device (1) sends a dial signal to connect a line with the target terminal device ( 3). After performing a logical connection (such as password exchange for confirming the other party) performed after the line connection with the terminal (3), an image status request, that is, a video input information request signal is transmitted to the terminal. Then, upon receiving the image status request, the image control signal circuit (32) including the video signal presence / absence detection unit of the terminal (3) receives an instruction from the CPU (33).
The switches (31) are sequentially switched to check the video signals from all the video signal input terminals (6).

The image control signal circuit (32) determines that the video input is valid when there is a video signal and a synchronizing signal accompanying it, and otherwise determines that the video input is invalid. The information is sent to the center device (1) as information via (33).

The center unit (1), which has received the above information (information on the connection state of the video signal input terminal (5)), reads the information and performs polling with the terminal unit (3).
An invalid video signal input terminal number of the terminal (3) (a terminal number with invalid video input) can be recognized. Then, the center device (1) instructs the terminal device (3) to transmit only an image from a valid video terminal number. Therefore, the terminal device (3) transmits only the image signal of the designated input terminal (6) to the center device (1).
In this case, as shown in FIG. 4, it is possible to perform polling of only valid images having video.

[0013]

As described above, according to the present invention, the center unit receives the presence / absence information of the video input from the terminal, and thereby receives the information from the video signal input terminal to which the video signal output device is not connected. since as brewing poll Shinano images, there is an effect that it is possible to perform good polling efficiency by shortening the polling time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a terminal.

FIG. 2 is a communication procedure diagram during a polling operation of the device of the present invention.

FIG. 3 is an operation flowchart of a center machine (1).

FIG. 4 is a flowchart of image display in the center machine (1).

FIG. 5 is a schematic diagram of a videophone device.

FIG. 6 is a communication procedure diagram during a polling operation of the conventional device.

[Explanation of symbols]

 1 center device 3 terminal device 5 video signal output device 6 video signal input terminal

Claims (1)

(57) [Claims] 1. A terminal having a plurality of video signal input terminals for connecting video signal output equipment, and polling an image signal connected to the terminal via a communication line and inputted to the plurality of video signal input terminals. Center that can do
In the television telephone apparatus and a chromatography machine, the center
The terminal sends an image status request to the terminal when making a logical connection made after the line connection with the terminal, and the video to the video signal input terminal transmitted from the terminal in response to the image status request. A videophone apparatus which receives input presence / absence information and performs polling without specifying the video signal input terminal without video input when polling with the terminal.