JPS6260868B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an information transmission system having a plurality of private line systems using, for example, facsimiles as terminals.

[Technical background of the invention and its problems]

In the past, multiple facsimile terminals were installed within the same workplace such as a factory or office, and facsimile communication was rarely performed within the same premises, but now many terminals are installed distributed within the same business establishment. For example, it is desired to be able to communicate between departments and sections. In addition, this private branch facsimile communication system must be connected to other private branch facsimile communication systems via a general public communication line (public telephone line) like a normal private telephone.

However, although public communication lines can actually be used over a fairly wide band, for example 300Hz
There are legal restrictions to use it only in the audio frequency band of ~4KHz. If the internal line facsimile communication system were to be based on low-speed equipment whose frequency band corresponds to the above band, image information could be sent directly to the public communication line via the private branch exchange. This is undesirable as it reduces the efficiency of use. On the other hand, high-speed machines use a frequency band that is much wider than the voice frequency band, and if an extension facsimile communication system using this is used, image information cannot be sent directly to a public communication line. However, extension communication lines can also be used in a frequency band much wider than the voice frequency band, and it is desirable to improve the efficiency of use of extension communication lines as an extension communication system for high-speed machines.

From this technical perspective, the inventors of the present invention developed a private line system that includes a plurality of facsimile terminals that transmit and receive image information at high speed compared to the transmission mode of image information on general public lines, and a system between these facsimile terminals. and an exchange means for connecting the facsimile terminal and the general public line;
means for converting image information on the general public line into a transmission mode of image information on the facsimile terminal, and converting image information on the facsimile terminal into a transmission mode of image information on the general public line. Furthermore, the present invention proposes a system characterized in that the switching means connects the facsimile terminal and the general public line via the converting means.

This system will be explained according to the drawings.
In FIG. 1, a plurality of terminals A ₁ -An can be connected to each other through a private branch exchange PBX, and can also be connected to a general public communication line O through a private branch exchange PBX and a data compression/expansion machine DCE.
I ₁ -In indicate private lines between each terminal A ₁ -An and the private branch exchange PBX. In the above, the data compression/expansion machine DCE is connected to a general public communication line O
When connected to the PBX, it is inserted into the transmission line at the PBX exchange.

The terminals A ₁ to An are installed in various configurations depending on the location requirements. For example, terminal A ₁ , An
is a telephone section t, a facsimile transmitting section f ₁ , and a facsimile receiving section
Consists of f ₂ . Further, the terminal A ₂ includes a telephone section t and a facsimile receiving section f ₂ . Terminal _A3 consists of a facsimile transmitting section _f1 and a facsimile receiving section _f2 , and does not have a telephone section. Terminals with full functions such as terminals A ₁ and An are installed in departments where both telephone calls and image transmission and reception are frequent, such as the general affairs department and the design department.
In addition, a terminal equipped with a facsimile receiving unit and telephone, such as terminal _A2 , is installed in a department such as a warehouse that only needs to receive slips. Terminals capable of only facsimile communication, such as the terminal _A3 , are installed, for example, in sales, accounting departments, etc. where invoices and the like are frequently sent and received.

The frequency bands used in the private lines are as shown in FIG. In other words, a band T of 0.3 to 4KHz is allocated to telephone calls, and a band T of 4K to 4KHz is allocated to facsimile communications.
A band F in a band 8 times the band T of 36KHz is allocated. The bandwidth of band F can be selected according to the compression ratio of the data compression/expansion machine. Considering that the current compression ratio is 1/5 to 1/8, it is 8 times the audio bandwidth mentioned above. The band width is appropriate. If more advanced data compression becomes possible in the future, the frequency band of the facsimile communication described above may be expanded.

According to the example described above, mutual communication between on-premises terminals can be performed at high speed over a wide band. In addition, when connecting to another private line facsimile communication system via a general public communication line, broadband data is subjected to a data compression/expansion machine and sent to the general public communication line as a signal in the audio frequency band. In other private line facsimile communication systems, the symbol is decompressed in a data compression/expansion machine, sent to the extension, and an image is created at the receiving terminal. That is, according to the present invention, it is possible to perform wideband, high-speed facsimile communication on a private line, and also to communicate with other private line facsimile communication systems via a general public communication line whose use is limited to the voice frequency band. can do.

In the embodiment shown in FIG. 1, only in the case of facsimile communication, a special tone or other identification code is added to the beginning of the signal to indicate that it is facsimile communication, and one of the terminals is connected to a general public line, Further, the data compression/expansion machine DCE may be inserted into the transmission path only when the identification circuit D detects this. In this way, telephone communication that does not require data compression/expansion will not go through the data compression/expansion machine, thereby increasing the efficiency of using the expensive data compression/expansion machine.

According to the above-mentioned system of the present invention, there is no need to install an expensive data compression/expansion machine for each terminal.
Since it is shared by many terminals, the entire system can be configured at a relatively low cost. In addition, the internal line, which was previously used only for telephone calls, can be shared with facsimile communications, greatly increasing the value of the internal line. Furthermore, since the terminals do not need to be equipped with a data compression/decompression function, they can be made relatively small and inexpensive, and can be easily distributed throughout the campus, making it possible to abolish or simplify the private delivery of documents, etc. within the campus. This speeds up communication using documents, etc.

However, when a plurality of such local private line systems are provided and the scale of the overall system increases, the system becomes complicated and the overall control becomes extremely complicated.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an information transmission method that eliminates the above-mentioned drawbacks and allows easier overall control of the system even when the system is composed of a plurality of local area line systems.

[Summary of the invention]

In an information transmission system in which small systems consisting of a plurality of information processing devices are locally arranged and information is sent and received between these small systems, the small systems are connected by a single transmission path via a switching means. In addition, during communication from an information processing device in the small system to an information processing device in another small system, the switching means switches information in the other small system from the information processing device in the small system to the information processing device in the other small system. It is characterized by prohibiting transmission to the processing device.

That is, within the first and second small systems,
The present invention is characterized in that it does not control all of the communications between N ₁ and N ₂ for N ₁ and N ₂ information processing devices, but is substantially limited to only one-to-one communications.

〔Effect of the invention〕

According to this invention, communication between a plurality of information processing devices is essentially limited to one-to-one communication by connecting the small systems through a single transmission path via a switching means, so the configuration is simple. become. or,
Control by the switching means does not require looking at the entire system (all of the multiple small systems); it is simply a control function that blocks calls from other terminals during communication from one information processing device. It is very easy to control. Moreover, communication between small systems is also performed reliably.

[Embodiments of the invention]

Next, an embodiment of the present invention will be described using FIG. 3. In this example, a system consisting of terminals A ₁ to An in a premises is set up as a small system, and communication between these terminals A ₁ to An is not performed, but communication between other premises line facsimiles is carried out via a general public communication line. It performs facsimile communication with the communication system, and replaces the configuration of the example shown in Fig. 1 with a PBX exchange and uses a changeover switch psw that selects any of the terminals A ₁ to An and connects it to the general public communication line O. is provided. The data compression/expansion machine DCE is inserted between the changeover switch and the communication line O. The above-mentioned changeover switch psw shall have a priority function, for example, when one terminal is communicating, it will have the function of blocking calls from other terminals, and when making a call, two switches will be set for communication line O. Time priority shall be given to prevent the above terminals from being connected. In the system of this embodiment, n-to-n communication is substantially one-to-one communication, and the switching means only has the above-mentioned temporal priority.
Its control becomes very easy. Furthermore, in this embodiment, it is possible to send and receive data via the general public communication line O using a high-speed terminal, thereby reducing line usage time during facsimile communication and reducing line usage fees. can. In addition,
By setting the changeover switch PSW so that it can be turned ON for all terminals at the time of reception, it can be operated as a simple broadcast communication receiver.

Furthermore, as shown in Figure 4, the frequency band used for the internal line line is divided into three frequencies: the telephone frequency band T from 0 to 4KHz, the facsimile transmission frequency band from 4K to 36KHz, and the facsimile reception band from 36K to 68KHz. By dividing the band into bands, telephone communication, facsimile transmission, and reception can be performed independently. That is, for example, in the terminal shown as _A1 in FIG. 1 or FIG. 3, during image transmission by the facsimile transmitter _f1 using the frequency band _F1 ,
When a facsimile communication call is made to this terminal, an image can be received by the facsimile receiving section _f2 using the frequency band _F2 .
In this embodiment as well, the extension line is connected to the external general public communication line via a data compression/expansion machine for both sending and receiving facsimile signals, and the data is compressed in a predetermined manner. The data is sent to the public communication line, decompressed and decompressed according to a predetermined compression, and sent to the extension.

The present invention is not limited to the above-mentioned examples. For example, the number of data compression/expansion machines attached to a private branch exchange PBX is not limited to one, but any number of them can be installed depending on the number of external lines connected to the private branch exchange, and the available data compression/expansion machine channels can be used. By doing this, you can minimize the number of busy times during facsimile communication. In addition, a buffer memory is attached to the data compression/expansion machine to temporarily store the compressed output and then transmit it according to the transmission conditions. By retransmitting according to the reception conditions, it is possible to adjust the transmission and reception speed and time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the internal line system that is the basis of the present invention, FIG. 2 is a diagram of the extension frequency band used therein, and FIG. 3 is a block diagram of an embodiment of the present invention. FIG. 4 is a diagram showing an example of the extension frequency band used. A ₁ ~An……terminal, I ₁ ~In……extension line,
PBX...private branch exchange, DCE...data compression/expansion machine, D...code identification circuit, O...general public communication circuit, T...telephone frequency band, F...facsimile frequency band.

Claims (1)

[Claims] 1. An information transmission method in which a plurality of small systems each consisting of a plurality of information processing devices each having at least a telephone section or a facsimile section are arranged locally and information is sent and received between these small systems. , the respective small systems are connected via a switching means, and the switching means is configured to connect the small systems so that the transmission from one information processing device in the small system is received earlier than the transmission from another information processing device. In this case, priority is given to the above 1.
enables communication between one information processing device and an information processing device in another system, and while the one information processing device is communicating, the other information processing device in the small system communicates with the other small system. An information transmission method characterized by prohibiting transmission to internal information processing devices.