JPS634740B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a facsimile terminal network connection system, and particularly to a facsimile terminal network connection method for connecting a facsimile terminal accommodated in a telephone switching network and a facsimile terminal accommodated in a data switching network using a packet switching method. This invention relates to a facsimile terminal network connection method.

One type of switching network that accommodates facsimile terminals is the telephone switching network shown in FIG. That is, each facsimile terminal 3 is connected to each other via a telephone switching network 1 consisting of a telephone exchange 2 and lines, and facsimile devices that communicate via this telephone network are subject to the International Telegraph and Telephone Advisory Committee. (hereinafter abbreviated as CCITT) has issued the following recommendations and is working towards international standardization.

(1) Recommendation T.2; Group 1, which uses a telephone line to transmit an ISO A4 size document in approximately 6 minutes (2) Recommendation T.3; Group 2, which transmits the same in approximately 3 minutes (3) Recommendation T.4: Group 3, which transmits the above in about 1 minute.Recommendation T.30 has also been issued as a transmission procedure when accommodating the above facsimile terminals in a telephone switching network.

Facsimile exchange using telephone exchange networks is the most widespread, as seen in the international standardization mentioned above.
This switched network is economical and suitable for terminal-to-terminal communication with relatively small traffic characteristics because it can utilize the regional spread of the telephone network.

However, since it is a switched telephone network, it takes a long time to connect a call, on the order of minutes, there are limits to transmission quality, and half-duplex communication makes line usage inefficient.

In order to address this shortcoming of the telephone switching network,
A new data network, shown in the figure, has been constructed. That is, each facsimile terminal 13 is interconnected from a packet switch 12 and a line via a packet switching network 11, and CCITT Recommendation X.25 has been issued regarding the interface between the terminal and the network. This new data network based on the packet switching method will
Call connection time in seconds, improved transmission quality through error retransmission, full duplex communication and packet multiplex communication to improve line usage efficiency, broadcast communication using file 14, proxy reception, priority control, storage of copies, etc. It has features such as service support functions.

However, since the packet switching network has a narrower regional spread than the telephone switching network and is constructed using new resources, communication costs are high for terminals with small-scale traffic characteristics.
Furthermore, in order to join a packet switching network,
It is necessary to add the terminal control unit TC shown in FIG. 2 and change the connection interface function of the terminal to one that can accommodate the packet switching network, which increases the cost of the terminal itself.

In order to compensate for the above-mentioned drawbacks, an inter-network connection system between a telephone switching network and a packet switching network has been considered, in which the subscriber section of the packet switching network is configured with a telephone network, and the present invention also applies to this system. It is related.
The conventional inter-network connection system is a system in which a telephone exchange is accommodated in a packet switching network by providing a communication control device in its relay trunk.

However, this conventional network connection system has the following drawbacks.

(1) In an outgoing connection from a telephone network terminal to a packet network terminal, in order to specify the terminal accommodated for packet switching by dial connection, the dial number corresponding to the terminal accommodated in the packet switched network is sent to the telephone switched network. need to be introduced.

(2) For outgoing connections using dialed numbers, the connection time will be longer in broadcast communications with many destinations.

(3) To use relay trunks for inter-network connections,
Requires changes to existing telephone exchange network equipment. Furthermore, if the relay trunk interface differs depending on the switching network, it is necessary to change the communication control device to match the interface.

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to improve the interface conditions of the existing telephone switching network.
A facsimile system that allows a facsimile terminal via a telephone switched network to be accommodated in a packet switched network without changing the numbering system, and allows economical mutual communication between this terminal and the facsimile terminal accommodated in the packet switched network. The purpose is to provide a terminal network connection method.

The present invention provides a facsimile packet switching device that is inserted between a packet switching network and a telephone switching network and can be called as a single terminal from both switching networks. During inter-network communication, each terminal first calls this network. In addition to calling a remote packet converter and sending it the other party's terminal code and communication service information to have this device relay between networks, additional commands provided in CCITT's Recommendation T.30 are It is characterized in that the identification codes of the originating and terminating terminals and communication service information are transferred using the .

Hereinafter, the present invention will be explained in detail with reference to Examples.
FIG. 3 is a diagram showing an example of the network configuration of the system of the present invention, in which a facsimile packet converter 21, which is a feature of the present invention, is installed between the telephone switched network 1 and the packet switched network 11.
is provided. In the figure, path P1 is a connection within the packet switching network, path P2 is a connection within the telephone switching network, path P3 is a connection between both switching networks, and path P4 is a connection within the telephone switching network.
shows a connection route between each terminal of two telephone switching networks via the packet switching network 11.

FIG. 4 shows that when communicating from the subscriber facsimile terminal 3 of the telephone switching network 1 to the subscriber facsimile terminal 3 of the packet switching network 11 in the system of the present invention,
That is, it is a diagram showing a connection system in the case of route P3 in FIG. 3. However, although this figure shows an example of a store-and-switch network in which a message storage file 14 is connected to a packet switch 12, a packet-switch network that does not have such a message storage file 14 and is based only on the X.25 communication protocol can also be used. It goes without saying that this is within the scope of the present invention.

In FIG. 4 (in addition, sections ~ are shown as sections indicated by dotted lines), in the connection phase via the telephone switching network 1, in the telephone phases 1 and 2 of the same figure, from the facsimile terminal 3. When calling the facsimile packet switching device 21 by dialing the number assigned to it and establishing the connection path, TSI (transmitting station identification) and NSS (non-standard (Device) In response to a command, the originating terminal 3 notifies the facsimile packet conversion device 21 of the originating terminal identification code, the terminating terminal identification code, and the service code.

Using this notified information, the facsimile packet converter 21 notifies the packet exchange 12 of a connection request and the other party's terminal address in a packet, and after receiving the connectable packet (signal CFR), sends a request to the originating terminal. 3. Transmission to the packet exchange 12 via the telephone network 1 and the facsimile packet converter 21 is carried out in accordance with Recommendations T.30 and X.25. The message stored in the packet switch 12 is delivered to the other party's facsimile terminal 13 by store-and-forward transfer in a normal packet switch network.

FIG. 5 is a diagram showing a connection sequence when communicating from the facsimile terminal 13 joining the packet switching network 11 to the facsimile terminal 3 joining the telephone switching network. In the figure, the sections ~ indicate the sections indicated by dotted lines. This case is also almost the same as that shown in FIG. 4, but the communication between the facsimile terminal 3 connected to the telephone switching network 1 and the facsimile packet converter 21 completely complies with Recommendation T.30, and the originating terminal The key point of the present invention is that the identification code and the destination terminal identification code are transmitted by an additional command.

FIG. 6 is a block diagram showing an embodiment of a facsimile packet conversion device which is a feature of the present invention. In the figure, accommodation line 32 is a two-wire telephone switching network subscriber line, and accommodation line 33 is a four-wire packet switching network subscriber line. The role of this device is to adjust the physical conditions and logical connection conditions of both line interfaces.

The packet line control section 27, which controls the packet switched network subscriber line 33 via the packet line modem 28, is constructed of hardware and software modules that support levels 1 to 3 of Recommendation X.25. Facsimile line control unit 26
is comprised of hardware and software modules that support connection control of the low-speed modem 29 and transfer of facsimile image information by the high-speed modem 30 in accordance with Recommendation T.30. The network control device 25 performs control such as sending dial pulses or detecting a ringing bell during the calling sequence of the subscriber line 32 of the telephone exchange network. controlled by The line changeover switch 31 is connected to the network control device 25, the low speed modem 29 or the high speed modem 3.
0 and line 32 in accordance with Recommendation T.30. Central processing unit 22
In addition to controlling the exchange of image information between the facsimile line control unit 26 and the packet line control unit 27 via the common memory unit 23, it also controls the entire module including call control for calling and disconnecting.

With recent advances in microcomputer technology, the central processing section 22, facsimile line control section 2
6. It is possible to configure a multi-microprocessor by applying a microprocessor to each of the packet line control sections 27, and this device can be configured with relatively small-scale hardware.

As described above, according to the present invention, a general-purpose high-speed facsimile terminal can be accommodated in a packet switching network via a telephone switching network, and the line cost for subscribers of the packet switching network can be reduced. can. Furthermore, when accommodating data into a packet switching network, there is no need to provide a conversion device for each facsimile terminal, and it is sufficient to install as many facsimile packet conversion devices as the number of simultaneous connections, which reduces the cost of conversion devices per terminal. It can be reduced to a large extent.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the configuration of a facsimile communication system using a telephone switching network, Figure 2 is a diagram showing a system configuration of facsimile communication using a packet switching network, Figure 3 is a diagram showing an example of the network configuration of the system of the present invention, and Figure 4 is a diagram showing a system configuration of facsimile communication using a packet switching network. FIG. 5 is a diagram showing the connection sequence from the telephone switched network to the packet switched network in the method of the present invention. FIG. 6 is a diagram showing the connection sequence from the packet switched network to the telephone switched network in the method of the present invention. 1 is a block diagram showing an embodiment of a packet conversion device; FIG. 1... Telephone switching network, 3, 13... Facsimile terminal, 11... Packet switching network, 21... Facsimile packet converter.

Claims (1)

[Claims] 1. A facsimile packet conversion device having a function of relaying signals on both switched networks is provided between a telephone switched network and a packet switched network, and In the case of inter-network communication in which a message is sent from one terminal to a second terminal of a facsimile subscriber of the other switching network, the first terminal first calls the facsimile packet converter and transmits the message to the second terminal. After transferring the identification code and the message, the packet converter transfers the message to the second terminal, and within the telephone switching network, the identification code and other information of the first and second terminals are transferred. A facsimile terminal network connection method characterized in that information necessary for communication is transferred in a command frame attached to a communication protocol.