RU2504098C2 - Method of providing fax service, internetworking function unit and terminal - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: after sending a multipage signal message to a called terminal, if a service layer of a called side internetworking function (IWF) unit does not receive message confirmation from the called terminal within a first time threshold, the service layer of the called side IWF unit generates the message confirmation and sends that message confirmation to a modem of the called side IWF; after receiving the CONNECT message from the modem of the called side, the service layer of the called side IWF receives the fax data sent by the modem of the called side IWF and stores said data of the next page in a buffer; and if the service layer of the called side IWF receives the message confirmation from the called terminal before the buffer overflows, the service layer of the called side IWF sends the received CONNECT message and the fax data in the buffer to the called terminal.

EFFECT: correct use of the fax service in a satellite link.

11 cl, 4 dwg

Description

Technical field

The present invention relates to the field of wireless communications, namely, to a method for providing a facsimile service, an interworking function unit, and a terminal.

State of the art

Due to the small space-time constraints and good real-time performance, wireless communication is becoming the most widely used communication method by users today. It allows you to provide many services of various kinds, such as voice, data, facsimile, etc. With the constant expansion of the field of human economic activity, the requirements for the service area, usability and flexibility of mobile communications are also growing, and this is the beginning of the use of satellites in this area.

The advantages of satellite communications are quite obvious: long range communications - communications can be carried out at any range in the area covered by the beam transmitted by the satellite; communication is resistant to interference associated with terrestrial phenomena; and can be installed in a short time. Satellite communications, however, have several disadvantages that need to be overcome, for example, delay and phase jitter, which affect traditional wireless services, for example, packet data service; and some services, such as a facsimile service, cannot be used correctly on a satellite link.

Since the delay in the satellite communication line is relatively large and is about 700 ms for signal transmission in both directions, taking into account the system delay, we can assume that a second delay is present in the satellite communication line in total. With such a relatively large delay, if data loss occurs, then the level of the transmission control protocol (TCP) will take more than 1 second to transmit one packet, and this problem is very difficult to circumvent even if TCP / IP (IP is the Internet protocol, Internet Protocol) has high processing efficiency. The facsimile service, however, is a synchronous transmission procedure that imposes certain requirements on time points, both when negotiating communication parameters and when transmitting data, and especially when negotiating communication parameters between pages of a multi-page fax message. Therefore, as soon as an excess of data appears or the coordination signal is delayed, the traditional facsimile procedure cannot function correctly, and accordingly, the facsimile service in the satellite communication line cannot be provided.

SUMMARY OF THE INVENTION

The present invention provides a method for providing a facsimile service, an interworking function unit, and a terminal for correctly using a facsimile service in a satellite communication line.

To solve the technical problem described above, the present invention proposes a method for providing facsimile communication services, including the following: after the service level of the called party's inter-working function (IWF) block transmits a multi-page signal to the called terminal, if confirmation the message was not received from the called terminal before the first time threshold, the service level of the called party IWF unit generates a message confirmation and transmits generated evidence supporting the message to the modem unit IWF called party; after the service level of the called party IWF block receives the CONNECT message transmitted by the called party modem, the service level of the called party IWF block receives the fax data transmitted by the modem of the called party IWF and stores the mentioned fax data in the buffer, and if the service level of the called party IWF receives confirmation of a message from said called terminal to buffer overflow, service level of called party IWF block transmits said received CONNECT message and facsimile buffer data to said called terminal.

Also, the method described above may have the following distinctive feature: if the service level of the called party IWF does not receive a message confirmation from the called terminal, before the buffer overflows, the current connection is disconnected.

Also, the method described above may have the following distinguishing feature: said buffer stores only one page of facsimile data.

Also, the method described above may have the following distinctive feature: after the service level of the called party's IWF block transmits an End Of Procedures message to said called terminal, if a message confirmation is not received from the called terminal before the second time threshold , the service level of the called party IWF unit generates a message confirmation and transmits this generated message confirmation to the modem of the called party IWF block, and also transmits a DISCONNECT message ("disconnected ") transmitted by the modem of the called party IWF to the called terminal.

Also, the method described above may have the following distinctive feature: rejection by the service level of the IWF block of the called side of the filling bits occurring at least a predetermined number of times in a row from the fax data transmitted by the modem of the called side IWF block.

The present invention also provides a method for providing a facsimile service, comprising the following: if the called terminal does not receive a confirmation message from the facsimile device of the called party after receiving the multi-page signal from the service level of the called party interworking function (IWF) unit, generating said a message confirmation terminal and transmitting this message confirmation to the called party IWF, saving the current fax data page le, not fully transmitted by the called party facsimile device, in the buffer and continuously transmitting the current page of facsimile data to the called party facsimile device.

The method described above may also have the following distinguishing feature: after the called terminal receives the multi-page signal, the method also includes receiving a new page of facsimile data transmitted by the service level of the called party IWF, and when the current facsimile data page , which is transmitted at the current moment of time, is transmitted in full and a confirmation message is received from the facsimile device of the called party, a new data page is transmitted facsimile communication in the facsimile device of the called party.

The present invention also provides an interworking function block (IWF) including a service level and a modem, wherein

the mentioned level of services includes:

a transmission unit configured to transmit a multi-page signal to the called terminal; and also configured to send a CONNECT message and facsimile data in the buffer to said called terminal, if a message confirmation from said called terminal is received before the buffer overflows;

a generating and transmitting unit configured so that: if a message confirmation from the called terminal is not received before the first time threshold occurs, after the said unit has transmitted a multi-page signal, the generating and transmitting unit generates a message confirmation and transmits this generated message confirmation to mentioned modem; and

a receiving unit configured to receive a CONNECT message and facsimile data transmitted from said modem, and to store this facsimile data in a buffer.

Also, the IWF may have the following distinguishing feature: the service level of said IWF also includes a disconnect configured to disconnect the current connection if a message acknowledgment returned from the called terminal is not received before the buffer overflows.

Also, the IWF unit may have the following distinctive feature: said modem is configured to receive a confirmation message sent from said formation and transmission unit, and is also configured to send a CONNECT message and facsimile data to a reception unit.

The present invention also provides a facsimile terminal, including:

a reception unit configured to receive a multi-page signal from a service level of an interworking function (IWF) unit, as well as configured to receive facsimile data transmitted by an IWF unit service level;

a generating and transmitting unit configured to generate a message confirmation and transmit this message confirmation to a service level of said IWF if the message confirmation is not received from the facsimile device to the called party after receiving a multi-page signal from the service level of said IWF;

a buffering unit configured to store the current page of facsimile data that is not completely transmitted to the facsimile device of the called party in a buffer; and

a transmission unit configured to transmit said facsimile data to the called party's facsimile device, wherein said facsimile data includes a current facsimile data page currently stored in the buffer.

Compared with the prior art, the method and apparatus of the present invention implement a facsimile service in a satellite communication line and allow to achieve a result consisting in the possibility of the correct use of a facsimile service in a satellite communication line, which was not possible at the existing level of technology, while also improving compatibility of wireless communication systems.

Brief Description of the Drawings

Figure 1 illustrates the use of a CDMA system in a satellite link and corresponding protocol layers;

FIG. 2 is a flowchart for typical coordination during a process performed between transmitting one page of facsimile data and transmitting the next page of facsimile data when implementing a digital facsimile service;

Figure 3 is a flowchart of a procedure performed by the called party IWF between adding one page and adding another page in accordance with the present invention; and

4 is a flowchart of a procedure performed by a called party terminal between adding one page and adding another page in accordance with the present invention.

Preferred Embodiments of the Present Invention

The present invention proposes the following solution: in the coordination procedure performed between receiving the current page and the next page on the receiving side of the facsimile, the system and the terminal interact with each other and continue to work correctly even with excess data by generating a virtual signal and opening a temporary buffer with to adapt to transmission with relatively high delays. The present invention can be applied to provide facsimile services not only in a satellite communication line, but also in other communication lines having a relatively high delay (for example, where the signal transmission delay in both directions can reach about 500 ms).

Figure 1 illustrates the provision of facsimile services in a satellite communication line and the corresponding hierarchical protocol system, the main elements of the system are: calling party fax machine, calling party terminal, calling party interworking function (IWF) block, called party IWF block, the called terminal and the fax machine of the called party, and FIG. 1 illustrates only one - the calling or called side, while the opposite side includes devices similar yustrirovannym and not shown in Figure 1. Moreover, the fax machine of the calling party and the fax machine of the called party, in addition to the fax machines themselves, can be other facsimile devices capable of realizing facsimile communication. In bold in FIG. 1, the protocol layer undergoes changes in the present invention. The IWF unit (called party IWF and called party IWF) includes a service level and a modem with a fax function, which is hereinafter referred to briefly as “modem”. The modem is used to modulate, demodulate data and process AT commands, for example, matching some commands at the service level of the IWF block. The modem, as a rule, includes software for processing fax protocols and a chip with a fax function, while the mentioned chip with a fax function consists of CSMV6 chips and is the equivalent of a modem pool (consisting of 6 modem chips). During data transmission, the calling party fax machine transmits data to the calling terminal, the calling terminal transmits data to the calling side IWF, the calling side IWF transmits data to the called side IWF, and the called side IWF transmits data to the called terminal, and then the called terminal transmits data to the called party's fax machine. In this case, the calling terminal transmits data to the service level of the calling side IWF unit, and the service level of the calling side IWF unit transmits data to the modem with the facsimile function of the called party IWF unit by means of the modem with the facsimile function of the calling party IWF unit, and then the modem with the facsimile function the called party IWF block transmits this data to the service level of the called party IWF block.

In the present invention, the following technical scheme is applied.

The establishment of communication, the termination of communication and the transition between the states of the current TCP / IP transmission are kept unchanged and are in accordance with the requirements defined in the TCP / IP protocol; the basic interaction procedure for coordinating the facsimile services defined in the traditional facsimile protocol and the sequence of its execution were also kept unchanged, with the following changes being made:

A) The called-party IWF block discards zero bits ("0") of padding that occur in the data a certain number of times in a row.

Namely, the service level of the called party IWF block discards the fill bits that occur a certain number of times in a row in the facsimile data transmitted by the modem of the called party IWF block, while the mentioned fill bits are usually zero ("0"),

A certain number of zero fill bits are added to the data transmitted by the modem of the called party IWF block to the service level of the called party IWF block; in accordance with the specification of the ITU-T protocol T.4, the presence of fill bits does not affect the printing of real data in the fax machine, therefore, a certain number of fill bits are discarded to prevent the transfer of unnecessary data to the terminal; the number of discarded fill bits depends on the fill method used in the modem of the IWF block.

B) In the process of negotiating the communication between pages on the called side, if the called terminal receives the MultiPage Signal (MPS) message transmitted from the service level of the called side IWF, it generates and transmits a message confirmation (Message Confirmation, MCF) the service level of the called party IWF, regardless of whether he received the MCF from the fax machine on the called side or not, at the same time it saves the data of the current page that is not completely transmitted to the fax machine on the receiving side, in a temporary buffer to ensure continuous data transfer; if the called terminal receives data of the next page transmitted at that time from the IWF of the called party, it receives this data in the standard way, while it does not transmit data of the next page until the data of the current page has been completely transmitted and received MCF from the fax machine on the called side.

C) In a communication negotiation process between pages on the called side, after the service level of the called party IWF transmits a multi-page signal to the called terminal, if it has not yet received the MCF from the called terminal within a certain period of time, it forms an MCF and transmits this MCF to the called party's IWF block modem. After the service level of the called party IWF block receives the CONNECT message (“connected”) from the modem of the called side IWF block, it stores the next page data transmitted by the modem of the called side IWF block in a temporary buffer, and if it receives the MCF from the called terminal to overflow of the temporary buffer, it sends the CONNECT message and the data in the temporary buffer to the called terminal; and if he does not receive the MCF from the called terminal until the temporary buffer overflows, he breaks the current connection in accordance with the standard procedure.

Proposed in the present invention, a method of providing facsimile services in a satellite communication line includes the following steps.

Step 110, the calling terminal reliably transmits the facsimile negotiation message and data to the facsimile application layer of the calling party IWF through the radio interface and all protocol layers, and processes said negotiation message and data in accordance with the facsimile communication protocol; after processing the data of one page, if this page is the last page, proceeds to step 120, otherwise, go to step 130.

Step 120, the calling party IWF and the calling terminal operate in accordance with the standard protocol procedure; after the service level of the called-side IWF block receives an End of Procedures (EOP) message from the modem of the called-side IWF block, it transmits it to the called terminal; if it does not receive MCF messages from the called terminal before the second time threshold, the service level of the called side IWF unit generates an MCF message and transmits it to the modem of the called side IWF block, while it sends a Disconnect Disconnect (DCN) message to the called terminal, taken from the called side IWF block modem. After the called terminal receives the DCN message, it first determines whether the data has been transmitted to the called party's fax machine completely or not, and ends the call in the standard way, if so; otherwise, it does not end the call until the data has been completely transferred; and then proceeds to step 150.

Step 130, the calling party IWF and the calling terminal operate in accordance with the standard protocol procedure; after the service level of the called party IWF block receives the MPS message, it transmits this message to the called terminal, and if it does not receive the MCF message from the called terminal before the first time threshold, the service level of the called side IWF block generates an MCF message and transmits this a message in the service level modem of the called party IWF, while it saves the message "CONNECT" transmitted by the modem of the called party IWF; at this time, the modem of the called side IWF block transmits the next page data to the service level of the called side IWF block, and the service level of the called side IWF block opens a temporary buffer for storing this data, and if it receives the MCF message from the called terminal until the temporary buffer is full, the service level the called party IWF transmits a “CONNECT” message and the data to the called terminal; and if the service level of the called party IWF does not receive the MCF message from the called terminal until the temporary buffer is full, it disconnects the connection in accordance with the standard procedure.

If the service level of the called side IWF block has already generated the MCF and transmitted it to the modem of the called side IWF block, then when it receives the MCF from the called terminal before the buffer overflows, the called side IWF block service level does not transmit the received MCF to the modem of the called side IWF block.

The size of said buffer typically includes only one page of facsimile data, but the present invention is not limited to this.

Step 140, the called terminal performs the following operation: after the called terminal receives the MPS message from the service level of the called party IWF, if it receives the MCF from the called party fax machine (this means that this page has been completely transmitted to the said fax machine ), then the MCF is transferred to the service level of the called party IWF; if he has not yet received the MCF from the called party fax machine, then the called terminal generates an MCF and transmits this MCF to the service level of the called party IWF block, at the same time it saves the data of the current page, which is not completely transmitted to the called party fax machine, in temporary buffer to ensure continuous data transmission to the called party's fax machine. If it receives subsequent facsimile data (for example, next page data) transmitted from the service level of the called party IWF, it receives data in a standard manner, namely, the called terminal receives the next page data after receiving the CONNECT message transmitted from the service level of the IWF the called party. After it completely transmits the data of the current page and receives the MCF from the fax machine of the called party, the called terminal transmits the data of the next page to the fax machine of the called party.

In this case, step 130 and step 140 can be performed in parallel.

Step 150, if there is another page, restarts from step 110; if this is the last page, then the procedure is completed in the standard way after receiving the EOP message from the terminal, if the terminal does not transmit EOP messages, they wait for a call to be reset when the waiting time from the modem of the called party IWF is exceeded and complete the procedure.

In the above procedure, the data transmitted from the modem of the called party IWF block to the service level of the called party IWF block is subject to the following processing: removal of zeros appearing n (n = 5) times in a row. The called party's IWF service level removes a certain number of consecutive fill bits from the fax data.

Consider, for example, an IWF unit and a terminal in a Code Division Multiple Acces (CDMA) system that provides digital facsimile services, in which case the Base Station Controller (BSC) and base transceiver system (Base Transceiver System, BTS) in the base station subsystem are connected via satellite link, however this case does not limit the present invention.

The negotiation procedure performed between the IWF and the terminal between page transfers on the satellite link includes the following steps:

Step 210, the calling terminal reliably transmits the facsimile negotiation message and data to the facsimile application layer of the caller’s IWF via the radio interface and all protocol layers (see FIG. 1), and processes said negotiation message and data in accordance with the facsimile communication protocol ( see figure 2); after processing the data of one page, if this page is the last page, proceeds to step 220, otherwise, go to step 230.

Step 220, the calling party IWF and the calling terminal operate in accordance with a standard protocol procedure; the service level of the called party IWF receives the “+ FET: 2” message (which is an EOP message in digital facsimile communication) and transmits it to the called terminal if it does not receive the “AT + FDR” message (which is an MCF message in digital facsimile communication) ) from the called terminal for a certain period of time, it generates the message “AT + FDR” and transmits it to the modem of the IWF block of the called party, and at the same time transmits the message “+ FHNG: 0” (which is a digital fax message DCN connection ), Transmitted IWF modem unit of the called party, the called terminal. After the called terminal receives the message “+ FHNG: 0”, it first determines whether the data has been transmitted to the called party's fax machine completely or not, and if so, it ends the call in the standard way; otherwise, it ends the call after the data has been completely transferred; proceeds to step 250.

Step 230; the calling party IWF and the calling terminal operate in accordance with a standard protocol procedure; after the service level of the called party IWF receives the “+ FET: 0” message (which is an MPS digital fax message) and transmits this message to the called terminal if it does not receive the “AT + FDR” message from the called terminal for 4 seconds (4 seconds are given solely as an example and are not a limitation of the present invention), the service level of the called party IWF unit generates an AT + FDR message and transmits this AT + FDR message to the service level modem of the called party IWF, about saves the message "CONNECT", transmitted from the IWF modem unit of the called party; at this time, the modem of the called side IWF block transmits data of the next page to the service level of the called side IWF block, and the service level of the called side IWF block opens a temporary buffer for storing this data, and if it receives the “AT + FDR” message from the called terminal until the temporary the buffer, the service level of the called-side IWF block transmits the “CONNECT” message and the mentioned data to the called terminal, and if it has not yet received the “AT + FDR” message from the called terminal after the temporary buffer is full, it breaks those uschee compound in accordance with the standard procedure; see figure 3.

Step 240, while performing step 230, the called terminal performs the following operation; after the called terminal receives the “+ FET: 0” message from the service level of the called party IWF, if it receives the “MCF” message from the called party fax machine, which means that the data on this page is transmitted to the called party fax machine in full, the message “AT + FDR” is transmitted to the called party IWF block service level; if at this moment the called terminal still has not received the “MCF” message from the fax machine of the called party, it generates the message “AT + FDR” and transmits this message to the service level of the called party IWF block, at the same time it saves the data of this page, which not completely transmitted to the called party fax machine, in a temporary buffer in order to ensure continuous transmission of data to the called party fax machine. If it receives the next page data transmitted by the service level of the called party IWF, it continuously receives this data in the correct manner, namely, after the called terminal receives the CONNECT message from the service level of the called party IWF, it receives the data of the next page, and after after the current page is completely transmitted and the message "MCF" is received from the fax machine of the called party, the called terminal transmits the data of the next page; if the CONNECT message from the service level of the called party IWF is not received in a timely manner, the called terminal terminates the current connection; also, if the MCF message from the called party fax machine is not received in a timely manner, the called terminal terminates the current connection. Details of this procedure are depicted in FIG.

Step 250, if there is another page, then you should restart from step 210; otherwise, the procedure ends in the standard way, if the EOR message is received from the terminal, and if the terminal does not transmit the EOP message, then the call should be waiting for the call to be completed when the waiting time from the modem of the called party IWF is exceeded and the procedure ends.

In the above procedure, data transmitted from the modem of the called party IWF unit to the service level of the called party IWF unit needs the following processing: removing zeros that occur 5 times in a row.

The present invention also provides an IWF unit that includes a service layer and a modem, wherein

the mentioned level of services includes:

a transmission unit that is used to transmit the multi-page signal to the called terminal; and is also used to send a connection message and facsimile data in the buffer to the called terminal if the message confirmation returned from the called terminal is received before the buffer overflows;

a generating and transmitting unit, which is used to generate a message confirmation and transmitting this message confirmation to said modem if a message confirmation has not been received from the called terminal before the first time threshold occurs after said transmission unit has transmitted a multi-page signal message;

a receiving unit, which is used to receive a CONNECT message and facsimile data transmitted from said modem, and to store this facsimile data in a buffer;

a disconnection unit, which is used to break the current connection if it does not receive a message confirmation from the called terminal before the buffer overflows; and

a data processing unit that is used to remove padding bits that occur at least a predetermined number of times in a row in facsimile data received by said reception unit.

The present invention also provides a terminal that includes:

a receiving unit, which is used to receive the multi-page signal from the service level of the IWF unit, and is also used to receive facsimile data transmitted from the service level of the IWF unit;

a generating and transmitting unit, which is used to generate a message confirmation and transmitting this message confirmation to the service level of the said IWF, if the message confirmation is not received from the called party facsimile device after receiving the multi-page signal from the service level of the IWF;

a buffering unit that is used to store in the buffer the current page of facsimile data that is not completely transmitted to the facsimile device of the called party; and

a transmission unit that is used for transmitting said facsimile data to a facsimile device of the called party, wherein said facsimile data includes a current facsimile data page stored in a buffer; it also transmits the next facsimile data page to the called party's facsimile if it has completely transmitted the current facsimile data page in the buffer and received a confirmation message from the called party's facsimile.

The above description is only preferred embodiments of the present invention, and does not limit its scope.

The present invention has other embodiments, and those skilled in the art can make, in accordance with the previous discussion, various modifications and changes without departing from the scope of the present invention, while all such possible modifications or changes fall within the scope of the claims.

Industrial applicability

The proposed method and device provide the ability to use facsimile services in a satellite communication line, which was not possible at the current level of technology, and increase the compatibility of wireless communication systems.

Claims (11)

1. A method of providing a facsimile service, in which: during a negotiation process between receiving a current page and a next page on a called side, after a service level of a block of an interworking function (IWF) of a called side transmits a multi-page signal to a called terminal if the first message confirmation is not received from the called terminal before the first time threshold, the service level of the called party IWF unit generates a second message confirmation and Reda is a second confirmation message to the IWF modem unit of the called party;
after the service level of the called party IWF block receives the CONNECT message transmitted by the called party modem, the service level of the called party IWF block receives the fax data of the next page transmitted by the modem of the called party IWF, and stores this fax data of the next page in to the buffer, and if the service level of the called party IWF receives the first acknowledgment of the message from the called terminal to the buffer overflow, then the service level of the called IWF the party transmits said received CONNECT message and said next page facsimile data in a buffer to said called terminal. 2. The method according to claim 1, in which if the service level of the called party IWF does not receive the first message acknowledgment from the called terminal to the buffer overflow, the current connection is disconnected. 3. The method of claim 1, wherein said buffer stores only one page of facsimile data. 4. The method according to claim 1, in which: after the service level of the called-party IWF block transmits an End Of Procedures message to said called terminal, if said first confirmation message is not received from the called terminal before the second time threshold , then the service level of the called-side IWF block generates the second message acknowledgment and transmits this generated message confirmation to the called-side IWF block modem, and also transmits the DISCONNECT message transmitted by the modem to the block IWF of the called party, the called terminal. 5. The method according to any one of claims 1 to 4, further comprising: dropping by the service level of the called side IWF block the fill bits occurring at least a predetermined number of times in a row from the fax data transmitted by the modem of the called side IWF block. 6. A method of providing a facsimile communication service in which:
if the called terminal does not receive the first acknowledgment of the message from the called party facsimile device after receiving the multi-page signal from the service level of the called party interworking function (IWF) block, said called terminal generates a second message acknowledgment and transmits this second message acknowledgment to the IWF of the called party, stores in the buffer the current page of facsimile data, which is not completely transmitted by the facsimile device of the called Orons, and continuously transmits the current facsimile data page to the called party's facsimile device. 7. The method of claim 6, wherein, after said called terminal receives said multi-page signal message, the method also includes: receiving a new page of facsimile data transmitted by a service level of the called party IWF, and when the current data page the facsimile message that is currently being transmitted is completely transmitted and the first acknowledgment of the message from the called party facsimile device is received, the transmission of a new page of facsimile data to the facsimile device the called party’s connection. 8. An interworking function block (IWF) comprising a service level and a modem, wherein said service level includes:
a transmission unit, configured to send a multi-page signal to the called terminal during a negotiation process between receiving the current page and the next page; and also configured to send the CONNECT message and facsimile data of the next page in the buffer to the called terminal, if the first acknowledgment of the message from the called terminal is received before the buffer overflows;
a generation and transmission unit, configured to form, during the coordination between the reception of the current page and the next page, a second message confirmation and transmission of this generated message confirmation to said modem, if the aforementioned first message confirmation from the called terminal is not received before the first time threshold after how said transmission unit has transmitted a multi-page signal; and
a receiving unit configured to receive a CONNECT message and said facsimile data of the next page from said modem and to store this facsimile data of the next page in a buffer. 9. The block of claim 8, in which the service level of said IWF block also includes a disconnect block configured to terminate the current connection if said first message acknowledgment from the called terminal is not received before the buffer overflows. 10. The unit of claim 8, wherein said modem is configured to receive a message confirmation from said forming and transmitting unit, and is also configured to send a CONNECT message and facsimile data to the receiving unit. 11. Facsimile terminal, including:
a reception unit configured to receive a multi-page signal from a service level of an interworking function (IWF) unit, as well as configured to receive facsimile data from a service level of an IWF;
a generating and transmitting unit configured to generate a second message confirmation and transmit this message confirmation to a service level of said IWF if the first message confirmation is not received from the called party facsimile device after receiving said multi-page signal from the service level of said IWF;
a buffering unit configured to store in the buffer the current page of facsimile data that is not completely transmitted to the facsimile device of the called party; and
a transmission unit configured to transmit said facsimile data to the called party's facsimile device, wherein said facsimile data includes a current facsimile data page currently stored in the buffer.

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