JPH0818945A - Data transmission method and data transmitter - Google Patents

Abstract

PURPOSE:To obtain the data transmission method able to properly respond to many transmission request signals even when many transmission request signals are received or a transmission request signals are successively received by the transmitter. CONSTITUTION:Transmission request signals R1-R8 received at any time are detected periodically at intervals of a prescribed period T and when the same data request is in existence in the same period, the requests are integrated into one request to transform the signals R1-R8 into transmission request signals Q1-Q6 produced discretely. Recorded video data V are continuously read based on the transformed transmission request signals Q1-Q6 and data streams DS1-DS6 corresponding to the transmission request signals Q1-Q6 are outputted in parallel. The data streams DS1-DS6 are sent corresponding to the received transmission request signals R1-R8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission method and a data transmission device for transmitting data recorded in a recording device in response to a request, and more particularly to an audio signal and a video signal (hereinafter referred to as a network) via a network. Called AV signal)
The present invention relates to a data transmission method and a data transmission apparatus which are preferable for use in an information supply system that must immediately respond to a large number of transmission requests that are input at any time, such as the above-mentioned distribution service.

[0002]

2. Description of the Related Art Services for providing various types of information via networks have begun to be started. As one of such information providing services, an AV signal distribution service called video on demand (VOD) is expected. This is a large amount of AV such as movies and TV programs.
This is a service in which data is recorded on a recording medium such as a disk in a service center and distributed in response to a request from a viewer. In order to provide such a service, data transmission is started from an arbitrary time on demand, and
What is needed is a data delivery device that can continue to deliver multiple data streams in response to multiple requests.

The structure of a data transmission device for distribution service of time series data such as video data, which has been used so far, will be described with reference to FIG. FIG. 8 is a diagram showing the configuration of the data transmission device. The data transmission device 80 is
It is composed of a recording device 81 and an output unit 82. Recording device 8
Reference numeral 1 is a recording medium for recording time-series data, which is composed of a large-capacity hard disk device or the like. Output unit 82
Accesses the recording device 81 in accordance with the input transmission request signal, reads the time-series data, and sequentially outputs the data.

The state of the time series data distributed by this data transmission device will be described with reference to FIG. FIG.
It is a figure which shows the time-series data delivered, (A) is a figure which shows the time-series data delivered, (B) is a figure which shows the data stream currently sent according to the input sending request signal. As shown in FIG. 9 (A), the time-series data V has a configuration in which seven blocks A to G are successively arranged. These seven blocks A to G are time series data V, respectively.
Is evenly divided into 1/7 and is time-series data having a length of time T.

FIG. 9B shows a data transmission state when the transmission request signals R81 to R88 are input to the time series data V. Since the data transmission device 80 starts transmitting the time series data V from the time when the transmission request signals R81 to R88 are input, the data streams DS81 to DS88 shown in FIG. 9B are generated. In this state, for example, when the data read position at the time when the transmission request signal R88 is input is shown on the time series data V,
As shown by the arrow in FIG. Transmission request signal R8
Since 2 and R83 are signals that are input at the same time, the same data can be read, but the data transmission device 8
0 reads out data at 7 locations at a time within a predetermined time.

[0006]

In the above-mentioned data transmission device, a maximum of n is required for n transmission request signals.
It was necessary to send out a single data stream, and for that purpose, it was necessary to read n times the data amount of the original time series data for the unit time per unit time. That is, in order to respond to a larger number of transmission request signals, a larger number of data streams had to be generated, and therefore a large amount of data, which was almost proportional to the number of the data streams, had to be read.
Therefore, no matter how fast the recording device is used,
When a huge number of transmission request signals are concentrated, the data transmission device is in a punctured state, and a state in which proper processing cannot be performed occurs.

Further, in the above-mentioned data transmission device, since data existing at irregular positions of time series data must be simultaneously read in order to generate a plurality of data streams, access time becomes long. ,
There was a problem that data could not be read efficiently. Further, in order to read a large amount of data, the recording device needs to use a recording device that can be accessed at high speed. However, such a high performance recording apparatus with a short access time is very expensive. Therefore, there has been a demand for realizing a data transmission device capable of coping with a large number of transmission request signals by using a low-priced recording device with a low speed access.

Therefore, an object of the present invention is to provide a data transmission method capable of appropriately responding even if a large number of transmission request signals input at arbitrary times are input or concentrated, and
It is to provide a data transmission device. Another object of the present invention is to provide a data transmission device having a recording means capable of efficiently reading out data and thereby realizing a recording device which can be realized even by using a recording device having a normal access speed, even if not particularly high speed. Especially.

[0009]

In order to solve the above problems, in the present invention, even if a large number of transmission requests are input, the number of data streams read from the recording device is the same so as not to increase in proportion. Sending requests that request the same data input within a cycle can be handled by reading the data once. Further, even if a large number of transmission requests are concentrated, a predetermined maximum number of data streams can handle those transmission requests. In addition, the data is arranged and recorded in a position where it is continuously read as much as possible to shorten the access time.

Therefore, the data transmission method of the present invention is
With respect to the time-series data recorded in the recording means, a request for sending the time-series data, which is normally input from a large number of request sources at any time, is periodically detected at a predetermined cycle, and the same data request is made in the same cycle. If there is, it is a data transmission method in which the reading process is performed once, and the time-series data of the recording means is continuously transmitted to each request source.

Further, the data transmission apparatus of the present invention has a recording means in which at least one type of time series data is recorded and a transmission request signal of arbitrary time series data input from the request source at any time. Transmission request detection means for detecting periodically, data reading means for continuously reading time series data corresponding to the periodic transmission request signal from the recording means, and the read time series data for the periodical data. And a data transmission unit for continuously transmitting to each request source based on the transmission request signal.

Further, the data transmission apparatus of the present invention has a recording means in which at least one kind of time series data is recorded and a transmission request signal of arbitrary time series data input from the request source at any time. Transmission request detecting means for periodically detecting, data reading means for continuously reading out time series data recorded in the recording means at a predetermined cycle, and the periodically sending out the read time series data And data transmission means for continuously transmitting data to each request source based on the request signal.

[0013] Specifically, the recording means arranges and records the data of each block at a position where continuous access or simultaneous access is possible for blocks obtained by dividing the time-series data into time intervals of the predetermined cycle. To do. In addition, specifically, the recording unit parallelizes each block with respect to a segment obtained by further dividing a block obtained by dividing the time-series data into time intervals of the predetermined period into predetermined data suitable for reading data once. In order to be readable, the segments of each block are mixed and each segment is continuously arranged and recorded in the order of each block.

Preferably, the recording means includes a plurality of recording devices capable of independently reading the recording data, and a selection means for sequentially selecting the recording devices from which the data is read according to the access load state of each recording device. Have. Specifically, the time series data is a signal including a video signal and / or a sound signal. Further, preferably, the predetermined detection cycle is set to a time within the response waiting time from the input of the transmission request signal to the reception of the requested data, which is the maximum allowable in the AV signal distribution service.

[0015]

According to the present invention, by assigning a transmission request input within a predetermined time T to one transmission request, a transmission request input at an arbitrary time is periodically transmitted with the predetermined time T as a cycle. It is converted into a signal, and data is read out and transmitted based on the periodic signal. as a result,
Even if the transmission requests are input most frequently, they have intervals of time T, and the maximum number of data streams is limited to the number obtained by dividing the total time of time series data by the predetermined time T. . Further, the recording means of the data transmission device of the present invention records the time series data by a method suitable for reading the time series data of the data transmission device of the present invention. That is, each block and each segment constituting the time-series data are arranged and recorded so that they can be continuously accessed or simultaneously accessed. Therefore, the access time when reading data can be made very short.

[0016]

Example will be described with reference to FIGS about data transmission apparatus of the first embodiment of the first embodiment the present invention. FIG. 1 is a diagram showing the configuration of the data transmission device of the first embodiment. The data transmission device 10 is
The recording unit 11, the request detecting unit 12, the reading unit 13, and the sending unit 14 are included.

The configuration and operation of each unit will be described. The recording unit 11 is a recording medium for recording time series data,
It consists of a large capacity hard disk drive. The request detection unit 12 synchronizes a transmission request signal that is input at any time at random times from a plurality of terminal devices 50 connected by a request input line 51 with a synchronization signal of a predetermined cycle, and discretely in that cycle. Converted to a generated send request signal. The converted periodic sending request signal is read by the reading unit 13 and the sending unit 1.
4 is input.

The reading unit 13 starts the reading of the time-series data in response to the periodic transmission request signal input from the request detection unit 12, and thereafter, continuously outputs the time-series data until the output of the series of time-series data is completed. Is read out and output to the sending unit 14. Since the length of one time series data is sufficiently longer than the cycle of the transmission request signal, the reading unit 13
A plurality of time series data streams having different read start times are output in parallel. Therefore, the reading unit 13 simultaneously reads the data at different positions of the time series data.

The term "simultaneous reading" means that reading is performed at the same time when a predetermined time is taken as a unit. The reading unit 13 reads, for example, 1-second time-series data in 1 / m second by one access, buffers it, and then outputs it as 1-second continuous data. Therefore, in reality, each data is sequentially read in a time division manner, but when viewed in units of 1 second, it can be said that a plurality of data are simultaneously read. Therefore, in this example, data at a maximum of m points can be read simultaneously, and m different data streams are generated.

The transmission unit 14 associates each data stream input from the reading unit 13 with the periodic transmission request signal input from the request detection unit 12, and each terminal device 50 that is the request source of each transmission request. To the data delivery line 52.

Next, with reference to FIG. 2, a state in which video data is recorded as time-series data in the data transmission apparatus of the first embodiment and the video data is transmitted in response to a transmission request signal. It will be specifically described. 2A and 2B are views showing video data sent from the data sending apparatus 10 of the first embodiment, FIG. 2A shows video data, and FIG. 2B shows a data stream sent according to a send request signal. It is a figure. The video data V, which is time-series data illustrated here, is video data composed of seven blocks A to G each having a time T, as shown in FIG.

It will be described that when a transmission request signal is input to the data transmission device 10, video data is read out based on the signal and transmitted as a data stream. First, as shown in FIG. 2B, the transmission request signals R1 to R8 input at arbitrary times are converted into the transmission request signals Q1 to Q6 in synchronization with the synchronization signal of the cycle T. That is, the signal R1 is converted into the signal Q1 and the signal R2 is converted into the signal Q2. Also, the signals R3 and R4 are
Since they are input within the same period within the time T, they are both converted into the signal Q3. Similarly, the signals R5 and R6 are converted into signals Q4 and Q5, respectively, and the signals R7 and R8 are both converted into signal Q6.

Next, based on the transmission request signals Q1 to Q6 generated at intervals of at least the predetermined period T or more,
The reading unit 13 sequentially starts reading data, and sequentially outputs the video data streams DS1 to DS6. In the reading section 13, a plurality of blocks must be read in order to send out these data streams DS1 to DS6. For example, in Figure 2.
As shown by the arrow in (A), at the time when the signal Q6 is input, the block G is sent to send the data stream DS2, the block E is sent to send the data stream DS3, and the block E is sent to send the data stream DS4. Block D for sending the data stream DS5 and block A for sending the data stream DS6.

The data streams DS1 to DS6 are
In the sending unit 14, the sending request signals Q1 to Q8 are associated with each other and sent as a response to those request signals. That is, the data streams DS1, DS2, DS
4, DS5 are transmission request signals R1, R2, R5, R6, respectively.
Is output as a response to. Also, the data stream DS
3 and DS6 are output as responses to the transmission request signals R3 and R4 and the transmission request signals R7 and R8, respectively.

As described above, the video data V composed of the seven blocks A to G sends the data stream, and therefore these blocks must be read at the same time. Therefore, the time for reading the individual blocks during the period T needs to be 1/7 or less of the period T. Further, the data stream transmitted in response to the transmission request signals R1 to R8 is the time for waiting for synchronization, that is,
The response may be delayed by the period T at the maximum. The video data V may be recorded in the recording unit 11 by any recording method and any data arrangement. However, as described above, it is important to read out as quickly as possible in order to cope with long-time video data, shorten the response waiting time, and secure an operation margin. For that purpose, regarding the data arrangement method in the first embodiment,
This will be described with reference to FIG.

FIG. 3 is a diagram showing the data arrangement when the time series data of the first embodiment is recorded on the hard disk, showing the state in which the data on the magnetic disk 40 is being read by the magnetic head 41. Is. As shown in FIG. 3, the video data V is continuously recorded on the magnetic disk 40 for each of the blocks A to G. By recording in such an arrangement, when reading the same block, it is sufficient to read data from consecutive positions, so that the access speed can be increased.

As described above, according to the data transmission apparatus of the first embodiment, the transmission request signal input at any time at any time is periodically detected at a predetermined cycle, and based on the cyclic signal. Data is being read and sent. Therefore, the transmission request signals input in the same cycle can be integrated into one transmission request signal, so that the data can be efficiently read. Further, as a result, even if a large number of transmission requests are input, the maximum number of data to be read at the same time can be determined, so that a data transmission device that can respond to an arbitrary number of transmission requests can be realized. Further, by recording the time-series data in the recording unit with the data arrangement as in the first embodiment, it becomes possible to perform video data for a longer time or synchronization in a shorter cycle, that is, quick response.

[0028] will be described with reference to FIGS about data transmission device of the second embodiment of the second embodiment the present invention. FIG. 4 is a diagram showing the configuration of the data transmission device of the second embodiment. The data transmission device 20 is
The recording unit 21, the request detecting unit 22, the reading unit 23, and the sending unit 24 are included. The recording unit 21 is a recording medium for recording time-series data and is composed of a large-capacity hard disk device. The request detection unit 22 receives from the plurality of terminal devices 50 connected by the request input line 51,
A transmission request signal that is input at random times is synchronized with a synchronization signal having a predetermined cycle, and is converted into a transmission request signal that is discretely generated in that cycle. The converted periodic transmission request signal is input to the transmission unit 24.

The reading section 23 sequentially reads the time series data from the recording section 21 and outputs it to the sending section 24. The reading unit 23 starts reading the time-series data with a read signal having a predetermined cycle generated in the internal circuit of the reading unit 23, and thereafter continuously reads the time-series data until the output of the series of time-series data is completed. Output. Since the length of one time-series data is sufficiently longer than the cycle of the read signal, the reading unit 23 needs to output a plurality of time-series data streams having different read start times in parallel, and the reading unit 23 Data at different positions of the time series data are read out simultaneously. The meaning of the simultaneous reading is the same as in the first embodiment.

The transmitting unit 24 allocates the data stream input from the reading unit 23 to the periodic transmission request signal input from the request detecting unit 22, and the data distribution line to each requesting terminal device 50. It is a sending means for sending out via 52. As described above, the reading unit 23
Regardless of whether or not there is a transmission request, a new data stream is generated at regular intervals T. Therefore, the sending unit 2
4 assigns a data stream newly read from the beginning of the time-series data to the transmission request signal input within the time T and outputs it.

Next, the data transmission device 2 of the second embodiment
0, video data is recorded as time series data, and a state in which this video data is transmitted in response to a transmission request signal will be specifically described with reference to FIG. 5A and 5B are views showing video data sent from the data sending device 20 of the second embodiment, FIG. 5A shows video data, and FIG. 5B shows a data stream sent according to a send request signal. It is a figure. The video data V illustrated here is composed of seven blocks A to G each of time T, as shown in FIG.

In the data transmission device 20 of the second embodiment, as shown in FIG. 2B, the reading of video data is sequentially started by the signals Q11 to Q18 of a predetermined cycle T generated inside the reading section 23. Then, a plurality of data streams DS11 to DS18 are generated. That is, the data streams DS11 to DS11 whose read positions are different by the time T
The DS 18 is generated regardless of whether or not there is a transmission request. Then, in the transmission section 24, the input transmission request signal R
Data streams DS11 to DS1 for 1 to R8
8 are appropriately associated and transmitted as a response to those request signals.

As described above, in the data transmitting apparatus 20 of the second embodiment, the reading unit 23 always generates a new data stream at a predetermined cycle, and the transmitting unit 24 selects and outputs the data stream according to the transmission request signal. are doing. This is equivalent to the state in which the transmission request signal is input every cycle in the data transmission apparatus 10 of the first embodiment, but a circuit for generating a transmission request signal synchronized with a predetermined synchronization signal from the transmission request signal is unnecessary. become.

FIG. 6 shows a recording method of the video data V suitable for use in the data transmitting apparatus of the second embodiment.
Will be described with reference to. 6A and 6B are views showing the arrangement of data when recording the video data of the second embodiment on a hard disk, where FIG. 6A shows the video data and FIG. 6B shows the data on the magnetic disk as a magnetic head. It is a figure which shows the state currently read by. As shown in FIG.
The video data V composed of two blocks A to G is
Each block is further divided into nine segments A1 to A9,
It is subdivided into B1 to B9, .... This subdivided segment is a unit for reading data. That is, within the period T, the segments A1, B1 to F1, G1, A2
G2, ..., A9 to G9 are read in a time-divisional order. As a result, the seven blocks A to G are read simultaneously in the time T.

Therefore, as shown in FIG. 6B, the order of reading the video data V on the magnetic disk 40 is as follows.
That is, the data A1, B1 to F1, G1, A2 to G
If the data is recorded in the order of 2, ..., A9 to G9, the magnetic head 41 only has to read the data sequentially and sequentially, and the access time can be extremely shortened without the need for random access. Therefore, according to the data transmission device of the second embodiment, it is possible to use a recording medium such as a magnetic tape which is sequentially accessed.

As described above, according to the data transmission apparatus of the second embodiment, regardless of the presence or absence of the transmission request signal, a plurality of data streams whose read positions are separated by the time T are generated and the data transmission request signal is responded to. Data stream is selected and output. As a result, in the reading, it is not necessary to judge whether to read or control read data. All the time series data may be sequentially read out in a predetermined order. Therefore, the control circuit for accessing the data is simplified and the access time is shortened. Therefore, when the number of transmission requests is very large and the data is read in almost every cycle, the second
The data transmission device of the embodiment is suitable. Further, by recording the time-series data in the recording section with the data arrangement as shown in FIG. 6, it becomes possible to perform video data for a longer time, synchronization in a finer cycle, that is, quick response.

[0037] will be described with reference to FIG. 7 for the data delivery device of the third embodiment of the third embodiment the present invention. FIG. 3 is a data transmission device 3 of the third embodiment.
It is a figure which shows the structure of 0. The data transmission device 30 includes a recording unit 31, a request detecting unit 32, a selecting unit 35, and a reading unit 3.
3 and a sending unit 34. The recording unit 31 includes a plurality of recording devices 31a to 31c. Request detector 3
2. The configurations and operations of the reading unit 33 and the sending unit 34 are the same as those of the request detecting unit 12, the reading unit 13, and the sending unit 14 of the first embodiment. The data transmission device 30 of the third embodiment,
Based on the read signal from the reading unit 33, the selecting unit 35 selects the recording devices 31a to 31c or the data read by the recording devices and outputs the selected data to the reading unit 33.

With such a configuration, the recording devices 31a-3
1c, the data is read out almost in parallel and the selection unit 3
By controlling the data transfer by 5, it is possible to reduce the access time by reducing the overhead such as the data seek time and the rotation waiting time, which depends on the recording device. In addition, when the recording device 31 is configured to be accessible from a plurality of data transmission devices, or is configured such that writing can be performed at the same time while reading,
It is also possible to have a configuration in which data is transmitted with priority over a recording device with a light load. In addition, each of the recording devices 31a to 3
1c includes blocks A to G of the time-series data described above, depending on the usage pattern and reading method of the data transmission device.
, Segments A1 to A9, B1 to B9, ..., G1
~ G9 may be arranged at any place. Also,
You may make it record in multiple recording devices redundantly.

In the above-described first to third embodiments, the transmission request for one type of time series data recorded in the recording section and the data transmission in response thereto have been described. However, the recording unit may have a configuration in which an arbitrary number of other types of time-series data are recorded. In that case, for each time series data,
The data transmission processing of this embodiment is independently performed in parallel. Further, in this embodiment, the input transmission request signal is a signal requesting transmission from the beginning of the time series data. However, it may be a signal requesting transmission from any place or transmission to any place.

[0040]

According to the present invention, the maximum number of data streams to be read is determined on the basis of the predetermined time T when the transmission request signals input at any time are integrated into one transmission request signal. Therefore, even if a large number of transmission request signals are input or concentrated, the number does not exceed the maximum number, and a data transmission method capable of appropriately responding even when there are a large number of transmission requests, and A data transmission device can be provided.

Further, when the time-series data is arranged and recorded so as to be suitable for the data reading method of this data transmission device, the access time for reading the data can be shortened. As a result, it is possible to realize a data transmission device that can efficiently read data and can respond to a transmission request that is input at any time, even if a recording device that has a relatively low access speed is used.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a data transmission device according to a first embodiment of the present invention.

2A and 2B are diagrams showing video data transmitted from the data transmission device shown in FIG. 1, FIG. 2A being a diagram showing video data, and FIG. 2B being a diagram showing a data stream transmitted in accordance with a transmission request signal. Is.

FIG. 3 is a diagram showing a method of recording video data in a recording section of the data transmission device shown in FIG.

FIG. 4 is a diagram showing a configuration of a data transmission device according to a second embodiment of the present invention.

5A and 5B are diagrams showing video data transmitted from the data transmission device shown in FIG. 4, FIG. 5A showing video data, and FIG. 5B showing a data stream transmitted according to a transmission request signal. Is.

6 is a diagram showing a method of recording video data in a recording section of the data transmission device shown in FIG.

FIG. 7 is a diagram showing a configuration of a data transmission device according to a third embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a conventional data transmission device.

9 is a diagram showing time-series data transmitted from the data transmission device shown in FIG. 8, (A) showing time-series data, and (B) showing a data stream transmitted in accordance with a transmission request signal. FIG.

[Explanation of symbols]

 10, 20, 30 ... Data sending device 11, 21, 31 ... Recording unit 12, 22, 32 ... Request detection unit 13, 23, 33 ... Readout unit 14, 24, 34 ... Sending unit 35 ... Selection unit 40 ... Magnetic disk 41 ... Magnetic head 50 ... Terminal device 51 ... Request input line 52 ... Data distribution line 80 ... Data sending device 81 ... Recording unit 82 ... Output unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Shiotani 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (8)

[Claims] 1. A request for sending arbitrary time series data of time series data recorded in a recording means, which is input at an arbitrary time from a request source, is periodically detected at a predetermined cycle, and is sent in the same cycle. A data transmission method in which when the same data is requested, it is continuously transmitted to each request source by one reading process. 2. A recording means in which at least one kind of time series data is recorded, and an arbitrary portion of a certain kind of time series data recorded in the recording means which is inputted at an arbitrary time from a request source. The transmission request signal of the time-series data of which is periodically detected at a predetermined cycle, and the time-series data corresponding to the periodic transmission request signal detected by the transmission request detection means is recorded. Data reading means for continuously reading from the means, and time-series data read by the reading means for continuously sending data to respective request sources based on the sending request signal detected by the sending request detecting means And a data sending device having means. 3. A recording means for recording at least one kind of time-series data, and an arbitrary portion of a certain kind of time-series data recorded in the recording means inputted at an arbitrary time from a request source. A transmission request detection unit that periodically detects a transmission request signal of time-series data at a predetermined cycle, and a data reading unit that continuously reads the time-series data recorded in the recording unit at a predetermined cycle, A data transmission device comprising: time-series data read by the reading means; and data transmission means for continuously transmitting the time-series data to each request source based on the transmission request signal detected by the transmission request detection means. 4. The recording means arranges and records the data of each block in blocks where the time-series data is divided into time intervals of the predetermined cycle, at positions where continuous access or simultaneous access is possible. 2 or 3
The described data transmission device. 5. The recording means parallelizes each block with respect to a segment obtained by further dividing a block obtained by dividing the time-series data into time intervals of the predetermined cycle into predetermined data pieces suitable for one-time data reading. 4. The data transmission device according to claim 2, wherein the segments of each block are mixed so as to be readable, and the segments are successively arranged and recorded in the order of the respective blocks. 6. The recording means comprises a plurality of recording devices capable of independently reading recording data, and a recording device for reading data based on an access load state of each recording device from the plurality of recording devices. The data transmission device according to any one of claims 2 to 5, further comprising selection means for sequentially selecting. 7. The time series data is a signal including a video signal and / or a sound signal, or a signal including either one of them.
The data transmission device according to any one of the above. 8. A response from the input of a transmission request signal to the reception of requested data, which is the maximum allowable in the distribution service of the signal including the video signal and / or the sound signal. The data transmission device according to claim 7, wherein the data transmission device is set within a waiting time.