JPS627287A - Still picture transmission - Google Patents

Abstract

PURPOSE:To perform extremely easier emergent interruption general broadcasting than that of a conventional method by setting interrupting channels in plural logic channels on shared transmission paths, and providing a command to select an interrupting channel. CONSTITUTION:An initial conditions, it is considered that terminals #1, 2 and #5 are connected to (0), (1) channels and the terminal #4 to 0.3 channels. In such a case, (0) channel is always commonly connects to whole channels. Under this situation, once TA (3, 1) commands are delivered through the channel (0), the whole terminals receive them but neglected except the terminal #3 as the result of decoding. At the terminal #3, a connecting channel turn to the channels (1) and also is set as T channel. Similarly a terminal #4 is connected with the channels 1 by the TA (4, 1) commands and are set as T channels. Thus, whole terminals #1-#5 go to a group which receives the general broadcast through the channels (1) and is TXA data are delivered, the whole terminals #1-#5 will receive the data to realize the interrupting general broadcasting.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to stationary transmission in a network in which a center station having an image data bank and a plurality of terminals are connected by a single shared transmission path (air waves may also be used). This invention relates to an image transmission method.

[Conventional technology]

The conventional technology will be explained assuming the network shown in FIG. In the figure, 10 is a center station (hereinafter referred to as the center) having an image data bank, 11 to 15 are terminals,
It is assumed that each terminal has terminal addresses #1 to #5.

Each terminal 11 to 15 is connected to the center 1 via a shared transmission line 16.
Connected to 0. On the other hand, data flowing on this transmission path 16 has a packet structure as shown in FIG.

This packet is composed of a header section 21 and a data section 22, and the header section 21 includes a channel field 23.
exists. This channel field 23 indicates the value of the logical channel to which the packet is transmitted, and each terminal uses this value to determine which logical channel each packet belongs to. As a result, multiple logical channels can be set even though it is physically a single shared transmission path. Among the plurality of logical channels, one channel that is always connected to all terminals is defined and defined as a common channel. Data sent through the common channel is received by all terminals. In this example, the operation will be explained for five terminals #1 to #5, but it is assumed that there are actually many other terminals.

Next, the operation will be explained.

When broadcasting a group of terminals, first the following command is sent to connect the terminals to the desired channel.

CA (n, m): Connect m channels to the terminal with terminal address n.

When a terminal with a terminal address n receives the above command sent using a common channel, it receives and decodes data that is subsequently transmitted via an m channel, that is, a packet whose channel field value is m. Note that if n is omitted, all terminals that receive this command are connected to channel m. The command is actually transmitted in the data section 22 of the packet as shown in FIG.

The operation of group broadcasting will be explained with reference to FIG.

First, in the initial state, only the O channel, which is a common channel, is connected to each terminal (301).

When the CA (1, 1) command is sent through channel O, all terminals receive it, but as a result of decoding, channel 1 is connected to terminal #l, and other terminals maintain their previous state (302). . From now on, terminal #1 will use channel 0
and channel 1 data will be received. Similarly,
CA (2,1), CA (3,2), CA (4,3
), CA (5,1) through channel 0, terminal #2 is sent to channel 1 . Channel 2 to #3, Channel 3 to #4. Channel 1 is connected to #5 (302-306). This will cause the terminal #
1. #2. #5 becomes one group that receives the broadcast.

Here, by sending data called TXA once through channel 1, terminals #1, #2, and so on are transmitted once. Since they are received simultaneously at #5, group broadcasting is realized (307
). Also, when transmitting TXB through channel 2, terminal #
Similarly, when data TXC is sent through channel 3, it is received only by terminal #4 (309).

Next, it is assumed that all terminals #1 to #5 broadcast emergency data called TXD. After this data TXD is urgently (interrupted) broadcast-received by all terminals #1 to #5, each terminal is returned to the previous reception connection channel. To perform this series of operations, first connect CA (3, 1) through the 0 channel,
Send the CA (4°1) command to terminal #3. #
4 to channel 1 (310, 311). As a result, terminals #1 to #5 become a group that receives broadcasting on channel 1. In this state, when TXD is sent through channel 1, it is received by all terminals #1 to #5 (312).

However, since the emergency (interruption) simultaneous broadcast is completed at this point, in order to return each terminal to the previous connection state, the CA
It is necessary to send commands (3, 2) and CA (43) (313, 314), and for this purpose, the center 10 manages the connection channels of each terminal before emergency broadcast (interrupt broadcast). need to be.

[Problem that the invention seeks to solve]

In this way, in the conventional method, when broadcasting an emergency interrupt broadcast, it is necessary for the center to manage the connection channels of each terminal before broadcasting the interrupt broadcast, and it is also necessary to revert to the previous connection state after broadcasting the interrupt. It was necessary to send a connection command to restore the connection.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a still image transmission method that can easily perform group simultaneous broadcasting (interruption broadcasting) of terminals.

[Means for solving the problem] For this purpose, the present invention provides
The center dynamically sets an interrupt channel (hereinafter referred to as T channel) from among a plurality of logical channels.

[Effect]

In this invention, the terminal connected to the T channel is
Afterwards, when the reception and decoding of the data transmitted through the T channel is completed, the T channel is automatically reconnected to the previous channel, and as a result, emergency interrupt broadcasting is possible.
The center does not send a reconnection command to the previous connection channel to the terminal (this can be easily done).

〔Example〕

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

The configuration diagram of a system for realizing an embodiment of the present invention is similar to that shown in FIG. 1, and terminal #1. #2. #5 is 1, terminal #3 is 2, terminal #4
shall have 3. In this embodiment, for the sake of explanation, the number of terminals is five, but it is assumed that there are actually many other terminals.

Each terminal is connected to the center 10 by a shared transmission path 16, and the data flowing on the transmission path 16 has a packet structure as shown in FIG. 2, as described above. Further, a packet is composed of a header section 21 and a data section 22, and a channel field 23 is present in the header section 21. A plurality of logical channels are set on a single shared transmission line 16, and among these, a channel that is always connected to all terminals is defined as a common channel.

Next, the operation will be explained.

The following commands are defined as commands transmitted from the center 10 to the terminals.

TA (n, m): Connect m channel to the terminal with terminal address n as T channel.

A terminal that has completed receiving and decoding data transmitted through a channel connected as a T channel automatically
It is assumed that the connection is reconnected to the connection channel before connection by the A command. This command is actually transmitted in the data section 22 of the packet as shown in FIG.

The actual operation will be explained with reference to FIG. First, in the initial state, terminal #1. #2. #5 is 0.1 channel, terminal #
It is assumed that terminal #3 is connected to the 0.2 channel, and terminal #4 is connected to the 0,3 channel.

Here, channel 0 is a common channel that is always connected to all terminals (401). In this state TA(3,1)
When a command is sent through channel 0, all terminals receive it, but as a result of decoding, it is ignored by terminals other than terminal #3. At terminal #3, the connection channel is changed to channel 1 and set as the T channel (402).

Similarly, the TA(4,1) command connects terminal #4 to channel 1 and sets it as the T channel (403)
. Now all terminals #1 to #5 are in a group that receives broadcasting through channel 1, and now T
When the data XA is sent, it is received and decoded by all terminals #1 to #5, and then transmitted to terminals #3. In #4, the channel 2 and channel 3 of the previous connection are automatically returned to realize interrupt broadcasting (404.405).

Next, when the command T A (2) is sent through channel 1, since the n field is omitted, terminal #1 connected to channel 1. #2゜All data of #5 is connected to channel 2 as T channel (406
). Then, when data TXB is sent to channel 2, terminal #1. #2゜#3. Since #5 is a group, it is received and decoded simultaneously, and then terminals #1, #2 and #5 return to channel 1, which was the previous connection (40
7,408).

In this way, in this embodiment, when simultaneously broadcasting emergency interrupts, a T channel dedicated to interrupts is set up, and each terminal automatically returns to the state before the interrupt after the interrupt. Broadcasting can be performed much more easily than in the past.

〔Effect of the invention〕

As described above, in the present invention, an interrupt channel is set among a plurality of logical channels on a shared transmission path, and a command is provided to specify it. Therefore, simultaneous broadcasting of emergency interrupts is much easier than before. There are some effects that can be done.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a transmission network system according to a conventional system and an embodiment of the present invention, Fig. 2 is a diagram showing the structure of a transmission packet in the system, and Fig. 3 is a command transmission format in an embodiment of the present invention. FIG. 4 is a diagram illustrating the transmission of interrupt broadcasting in an embodiment of the present invention, and FIG. 5 is a diagram illustrating the command transmission format of the conventional example.
FIG. 6 is a diagram showing the state of transmission during broadcasting in a conventional example. 10... Center, 11-15... Receiving terminal, 16
. . . Shared transmission path, 21 . . . Header section of the transmission packet, 22 . . . Data section of the transmission packet, 23 . . . Channel field of the transmission channel. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) When transmitting packets of still image data from a center station that has a still image data bank to multiple terminals via a single shared transmission path with multiple logical channels set up, an interrupt channel is used as a network At the same time, transmit a command to temporarily connect the interrupt channel to a desired terminal, and use the interrupt channel to transmit still image data in an emergency.
A still image transmission method characterized by broadcasting interrupts all at once.