JP2001094624A - Protocol converter and communication system using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the occurrence of 'abnormal end' due to line interruption caused by deteriorated quality of a wired channel in FAX communication by a mobile phone. SOLUTION: A T-ADP (transmitter side protocol converter) 3-2 transmits a line interrupt signal (DCN signal) to an R-ADP (receiver side protocol converter) 3-3 to start a timer, and transmits a data communication release request to the R-ADP 3-3 when receiving a DCN acknowledgement signal from the R-ADP 3-3 or the timer expires. Upon the receipt of a line interrupt signal from the T-ADP 3-2, the R-ADP 3-3 transmits the line interrupt signal to an R-FAX (receiver side FAX) 3-4, and transmits a line interrupt signal transmission confirming signal to the T-ADP 3-2 and terminates the communication when receiving the data communication release request without starting the timer or the timer expires without reception of the data communication release request.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a protocol conversion apparatus in a digital portable car telephone type facsimile communication and a communication system using the same.

[0002]

2. Description of the Related Art In a digital portable car telephone system, a PSTN (Public Switched Telephone Network) is used.
(Fixed telephone network, public network)
Since the retransmission delay greatly fluctuates due to the characteristics of the wireless section, the throughput decreases. Because of this delay, T.D. Three
A problem arises in that a timer in protocol 0 (a protocol for FAX communication used in a wired line) times out.

In order to solve such a problem, the current PDC (Pers
onal Digital Cellular (digital car phone) FAX communication is based on T. The T.30 protocol is terminated by a protocol converter, and the sequence between the transmitting-side FAX (facsimile) and the transmitting-side protocol converter and the sequence between the receiving-side FAX and the receiving-side protocol converter are controlled independently. The delay of 30 protocol sections is reduced to prevent the timer from timing out.

[0004]

However, in the configuration of the conventional FAX communication system as described above, it is difficult to match the timing of the transmission-side sequence with the reception-side sequence, and therefore, the shift of the FAX phase between the transmission side and the reception side is difficult. May occur, and a fax communication error may occur.

[0005] As a practical problem, if a delay occurs in the image signal transmission of the receiving-side wired line, the FAX-protocol converter of the transmitting side and the FAX-protocol converter of the receiving side shift in the FAX transmission phase. Even though the protocol conversion device is transmitting image data to the reception-side FAX, the transmission-side protocol conversion device transmits a DCN (Disconnect) signal, which is a line disconnection signal, to the wireless section, and disconnects the line. When the receiving-side protocol converter receives the data communication release request signal, the line is disconnected even though image data is being transmitted to the receiving-side FAX, so there is a point to be solved in which FAX communication ends abnormally.

FIG. 2 shows an example of the above-described FAX communication abnormal end sequence in the conventional FAX communication system. In the figure, reference numeral 2-1 denotes a T-FAX (transmission side FA).
X), 2-2 denotes a T-ADP (transmission-side protocol conversion device), 2-3 denotes an R-ADP (reception-side protocol conversion device), and 2-4 denotes an R-FAX (reception-side FAX).

When the line quality in the wired section between the R-ADP 2-3 and the R-FAX 2-4 is poor, the R-FAX 2-4
Error occurs in the image signal received from the R-ADP 2-3.
G3-FAX ECM (Error
In the Correction Mode) mode, the R-FAX 2-4 requests the R-ADP 2-3 to retransmit the image signal.
It takes extra time to transmit the image signal from the ADP 2-3 to the R-FAX 2-4. If this time is long, the transmitting side (the T-FAX 2-1 and the T-ADP 2
-2), the fax transmission phase is shifted, and the above T-A
A line disconnection signal is sent from DP2-2 to R-ADP2-3. That is, R-ADP2-3 is
Despite the C phase (image signal transmission mode), T-
ADP2-2 goes into the E phase (line disconnection mode). The C phase (image signal transmission mode) and the E phase (line disconnection mode) are described in ITU-T Recommendation T.30. 30.

As described above, in the conventional FAX communication system and protocol conversion device, the line is disconnected when the data communication release request is received. As a result, when the line quality in the wired section is poor, R-ADP2-3 which is the protocol converter (base station side) is G3FAX
Although the image signal is being transmitted to the R-FAX 2-4, which is the receiving FAX, the R-ADP 2-3, which is the protocol conversion device (terminal side), disconnects the line, and the protocol conversion device (the base station side). 2-3 is a protocol converter (terminal side)
Upon receiving the line disconnection from 2-3, the FAX communication ends abnormally.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems.
An object of the present invention is to provide a protocol conversion device capable of avoiding abnormal termination of line disconnection that occurs when the quality of a wired line is poor, and a communication system using the same.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, a mobile station is built in or connected to a mobile station, connected to a network via a radio base station, and connected via a radio section. In the protocol converter for transmitting and receiving data signals by using the second protocol converter connected to the network side,
When a line disconnection signal is received from a first protocol conversion device built in or connected to the mobile station, and all of the transmitted data signals are transmitted to a destination communication device, the first Means for transmitting a transmission acknowledgment signal for the line disconnection signal to the protocol conversion device.

Here, the second protocol conversion device starts the timer after transmitting the acknowledgment signal, and receives a data communication release request from the first protocol conversion device during the timer startup. Alternatively, means for terminating communication when the timer has timed out may be provided.

Further, the second protocol conversion device includes:
When terminating the communication, the terminal itself may transmit a data communication release request to the first protocol converter.

Further, the second protocol conversion device includes:
The data signal may be converted into a facsimile communication protocol used on a wired line.

In order to achieve the above object, the invention according to claim 5 is a protocol conversion apparatus which is built in or connected to a mobile station, is connected to a network side via a radio base station, and transmits / receives a data signal via a radio section. Wherein the first protocol converter built in or connected to the mobile station transmits a line disconnection signal after transmitting all of the data signals, and the second protocol converter connected to the network side Means for receiving an acknowledgment signal for the disconnection signal.

Here, the first protocol conversion device is configured to start a timer after transmitting the line disconnection signal, and to receive the acknowledgment signal from the second protocol conversion device while the timer is running. Alternatively, a means for terminating communication when the timer has timed out may be provided.

Further, the first protocol conversion device comprises:
When terminating the communication, a request for releasing data communication is transmitted to the second protocol converter.

Further, the first protocol converter includes:
The data signal may be converted into a facsimile communication protocol dedicated to a wireless section.

In order to achieve the above object, a ninth aspect of the present invention relates to a first protocol conversion device built in or connected to a mobile station, and a first communication device connected to the first protocol conversion device. The mobile station transmitting a data signal transmitted from the first communication device to a wireless section, and the data signal transmitted to a second protocol converter connected to a network via a radio base station, The data signal is transmitted to the second communication device of the transmission destination via the second protocol conversion device, and the data signal transmitted from the first communication device is received by the second communication device. In the system, the first protocol converter transmits a line disconnection signal after transmitting all the data signals,
Means for activating a timer after transmitting the line disconnection signal, and receiving a delivery confirmation signal for the line disconnection signal from the second protocol converter during the timer activation, or when the timer has expired. Means for transmitting a data communication release request to the second protocol converter and terminating the communication, wherein the second protocol converter receives the line disconnection signal, and Means for transmitting the acknowledgment signal to the first protocol conversion device when a signal is sent to the second communication device; means for activating a timer after transmitting the acknowledgment signal; During the reception of a signal for releasing data communication from the first protocol conversion device, or when the timer has timed out, Characterized by comprising a means for terminating the transmission to communicate a release request of a data communication to the first protocol converter.

Here, the first communication device is a portable facsimile terminal, the second communication device is a facsimile device connected to a wired line, and the first protocol conversion device is the portable facsimile device. Means for converting the data signal sent from the terminal to a facsimile communication protocol dedicated to a wireless section, wherein the second protocol converter uses the data signal sent via the wireless section over a wired line. A means for converting to a facsimile communication protocol is provided.

[0020]

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

FIG. 1 shows a facsimile apparatus according to an embodiment of the present invention.
1 shows a configuration example of a communication network. In the figure, reference numeral 1-1 denotes a portable FAX terminal, 1-2 denotes a protocol converter (terminal side), 1-3 denotes a mobile phone terminal, 1-4 denotes a wireless base station (mobile phone network), 1-5. Is IWF (In
ter Working Function) A protocol converter (protocol converter in the exchange) (base station side), 1-6 is a wired line (PSTN), and 1-7 is a G3 standard FAX device (hereinafter, referred to as G3 FAX).

In FIG. 1, a portable FAX terminal 1-1 is
Mobile phone terminal 1-3 and protocol converter (terminal side) 1
-2 for transmitting and receiving FAX data.
When transmitting an image signal from the portable FAX 1-1 to the G3 FAX 1-7, the protocol converter (terminal side) 1-2 is connected to the portable FAX terminal 1 through a wired line interface.
Received from T.1 It converts the 30-procedure signal and the image signal into a FAX procedure signal and an image signal dedicated to the wireless section, and transmits them to the mobile phone terminal 1-3. The mobile phone terminal 1-3 transmits the FAX procedure signal and the image signal dedicated to the wireless section to the IWF protocol conversion device (base station side) via the wireless base station 1-4 connected wirelessly (mobile phone network). Send to 1-5.

IWF protocol converter (base station side) 1
-5 indicates that the above-mentioned FAX procedure signal and image signal dedicated to the wireless section are transmitted to the T.D. The signal is converted into a 30-procedure signal and an image signal and transmitted to the G3 FAX 1-7.

The portable fax terminal 1-1 is a G3 fax.
Similarly, when receiving an image signal from 1-7, the protocol conversion device (terminal side) 1-2 and the protocol conversion device (base station side) 1-5 convert a protocol and perform FAX communication.

The operation from the end of image signal transmission to the line disconnection, which is a feature of the present invention, will be described below.

FIG. 3 shows an FA according to an embodiment of the present invention.
4 shows an example of an X communication sequence. In FIG.
1 is T-FAX (sending FAX), 3-2 is T-ADP
(Transmission-side protocol converter) 3-3 is R-ADP
(Receiver protocol converter) 3-4 is R-FAX
(Receiving-side FAX).

As shown in FIG. 1, a T-ADP (transmitting-side protocol converter) 3-2 outputs a line disconnection signal (DCN signal) to an R-ADP (receiving-side protocol converter) 3-3.
When the DCN delivery confirmation signal is received from the R-ADP3-3, a data communication release request is sent to the R-ADP3-3.

The R-ADP (receiving-side protocol converter) 3-3 receives a line disconnection signal (DCN signal) from the T-ADP (transmitting-side protocol converter) 3-2.
A line disconnection signal is transmitted to the R-FAX (reception-side FAX) 3-4, and the fact that the reception side has shifted to the line disconnection mode is indicated by DC.
The T-ADP 3-2 is notified by the N acknowledgment signal.

However, in consideration of the case where the line disconnection signal in the wired section and the wireless section becomes invalid, the T-ADP (transmission side protocol converter) 3-2 transmits the line disconnection signal to the R-ADP.
(Reception-side protocol converter) After transmission to 3-3, and R-ADP 3-3 transmits a DCN acknowledgment signal to T-ADP
After the transmission in 3-2, a timer is provided to start timing a preset time. As a result, as described below,
FAX communication ends normally even when the phases on the transmitting side and the receiving side are shifted.

FIG. 4 is a flowchart showing an operation example of the transmission-side protocol converter (T-ADP) 3-2 in FIG. 3 when the line is disconnected.

First, the transmission-side protocol converter 3-2
When receiving the line disconnection signal (DCN signal) from the transmission-side FAX 3-1, the final image data is transmitted to the reception-side protocol converter 3-3 on the wireless side (step S4).
1) Transmit a line disconnection signal (DCN signal) to the wireless-side receiving-side protocol converter 3-3 (step S42).
At the same time, a timer T1 for counting the timing of sending a data communication release request to the wireless side is started (step S43).

Upon receiving the DCN acknowledgment signal from the receiving-side protocol converter 3-3 (step S44), the transmitting-side protocol converter 3-2 stops the timer T1, and the wireless-side receiving-side protocol converter 3-3. Then, a data communication release request is sent to No. 3 and the communication is terminated (step S46).

The transmission-side protocol converter 3-2
When the timer T1 times out (step S45) because the DCN delivery confirmation signal cannot be received and the timer T1 times out (step S45), a data communication release request is sent to the wireless-side receiving-side protocol converter 3-3 to end the communication (step S46). ).

FIG. 5 is a flowchart showing an operation example of the receiving-side protocol converter (R-ADP) 3-3 shown in FIG. 3 when the line is disconnected.

First, the receiving side protocol converter 3-3
When a line disconnection signal (DCN signal) is received from the transmitting-side protocol converter 3-2 on the wireless side, the receiving side F
After transmitting the final image data to the AX3-4, the receiving FAX3
4 at the same time as sending the DCN signal (step S5).
1) A DCN transmission acknowledgment signal is transmitted to the transmission-side protocol conversion device 3-2 (step S52), and a timer T2 for measuring the timing of sending a data communication release request to the wireless side is started (step S53).

Thereafter, upon receiving a data communication release request from the transmission protocol converter 3-2 on the radio side (step S54), the transmission protocol converter 3-2 on the radio side is received.
Sends a data communication release request to the timer, stops the timer T2, and ends the communication (step S56).

When a data communication release request cannot be received from the wireless-side transmitting-side protocol converter 3-2, and the timer times out (step S55), the wireless-side transmitting-side protocol converter 3-2 transmits data communication to the wireless-side transmitting-side protocol converter 3-2. A release request is sent, and the communication is terminated (step S56).

FIG. 6 shows a protocol converter connected to the mobile device (or built in the mobile device) for realizing the present invention, between the "protocol converter connected to the network side". Shows the functional blocks required for communication. In the figure, reference numeral 6-1 denotes a judgment circuit, and 6-2 denotes an EOP (end
of page) / DCN transmission unit, 6-3 is a data communication release request transmission unit, and 6-4 is a timer control unit.

Upon receiving the line disconnection signal (DCN signal) from the transmitting FAX 3-1, the decision circuit 6-1 transmits the EOP / line disconnection signal (DCN signal) transmission instruction after transmitting the final image data, and transmits the EOP / DCN transmission instruction. At the same time as outputting to the unit 6-2, an instruction to start the timer T1 is output to the timer control unit 6-4.

The EOP / DCN transmitting section 6-2 sends a line disconnection signal (DCN signal) to the receiving-side protocol converter 3-3 on the wireless side in response to the instruction. Further, in response to the timer start instruction, the timer control section 6-4 starts the timer T1.

After receiving the DCN delivery confirmation signal from the receiving side protocol converter 3-3, the decision circuit 6-1 outputs a timer stop instruction to stop the timer T1 to the timer control section 6-4.

The timer control 6-4 outputs a data communication release request transmission instruction to the data communication release request transmitting section 6-3 in response to a stop instruction of the timer T1 or a timeout of the timer T1. The data communication release request transmitting unit 6-3 transmits a data communication release request to the wireless side according to the instruction.

The circuit of the hardware configuration of FIG. 6 operates according to the flowchart of the transmitting-side protocol converter of FIG.

FIG. 7 shows the communication between the protocol converter connected to the network and the "protocol converter connected to the mobile side (or built in the mobile unit)" for realizing the present invention. Shows the functional blocks required for In the figure, reference numeral 7-1 denotes a judgment circuit, 7-2 denotes a DCN acknowledgment signal transmission unit, 7-3 denotes a data communication release request transmission unit, 7
-4 is a timer control unit.

Upon receiving the line disconnection signal (DCN signal) from the wireless-side transmitting-side protocol converter 3-2, the determining circuit 7-1 transmits the final image data to the receiving-side FAX 3-4 and then transmits the DCN signal. At the same time, it outputs a DCN acknowledgment signal transmission instruction to the DCN acknowledgment signal transmission unit 7-2 and outputs an instruction to start the timer T2 to the timer control unit 7-4.

The DCN acknowledgment signal transmitting section 7-2 sends the DCN to the transmitting side protocol converter 3-2 in response to the instruction.
Transmit the delivery confirmation signal. Also, the timer control unit 7-4
Starts the timer T2 for measuring the timing of transmitting the data communication release request to the wireless side in response to the timer start instruction.

After receiving the data communication release request from the transmission protocol converter 3-2 on the wireless side, the determination circuit 7-1 outputs an instruction to stop the timer T2 to the timer control section 7-4.

The timer control 7-4 issues a data communication release request transmission instruction in response to a stop instruction of the timer T2 or a timeout of the timer T2.
Output to 3. In response to this instruction, the data communication release request transmitting unit 7-3 responds to the instruction by the transmission protocol converter 3 on the wireless side.
-2, a data communication release request is sent to end the communication.

The circuit of the hardware configuration shown in FIG. 7 operates according to the flowchart of the receiving side protocol converter shown in FIG.

(Other Embodiments) The protocol converter according to the present invention may be provided with both the functions shown in FIGS. 6 and 7 as an integral unit. In this case, the operation of FIG. 4 is performed when connecting (or incorporating) to the mobile device side, and the operation of FIG. 5 is performed when connecting to the network side.

An object of the present invention is to provide a recording medium (storage medium) recording software program codes for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer for the system or the apparatus. Needless to say, the present invention is also achieved when the CPU (or the CPU or the MPU) reads out and executes the program code stored in the recording medium. In this case, the program code itself read from the recording medium realizes the function of the above-described embodiment, and the recording medium on which the program code is recorded constitutes the present invention.
As a recording medium for recording the program code and for recording variable data such as a table, for example, a floppy disk (FD), a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, or the like can be used.

[0052]

As described above, according to the present invention,
In the facsimile communication by the mobile phone, there is an effect that it is possible to avoid abnormal termination of the line disconnection that occurs when the quality of the wired line is poor.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration example of a FAX communication network according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a FAX communication abnormal termination sequence in a conventional FAX communication method.

FIG. 3 is a diagram illustrating an example of a facsimile communication sequence according to an embodiment of the present invention.

4 is a transmission-side protocol converter (T-AD) shown in FIG.
It is a flowchart which shows the operation example at the time of line disconnection of P) 3-2.

FIG. 5 is a diagram showing a receiving-side protocol converter (R-AD) shown in FIG. 3;
It is a flowchart which shows the operation example at the time of line disconnection of P) 3-3.

FIG. 6 is a diagram illustrating a protocol conversion device connected to the mobile device (or built in the mobile device) for realizing the present invention, which is necessary for communication between the “protocol conversion devices connected to the network side”; FIG. 2 is a block diagram illustrating various functional blocks.

FIG. 7 is a diagram illustrating a protocol conversion device connected to the network for realizing the present invention, which is necessary for communication between “protocol conversion devices connected to the mobile side (or built in the mobile device)”; It is a block diagram showing a functional block.

[Explanation of symbols]

 1-1 Portable FAX Terminal 1-2 Protocol Conversion Device (Portable Terminal Side) 1-3 Mobile Phone Terminal 1-4 Wireless Base Station 1-5 Protocol Conversion Device (Base Station Side) 1-6 PSTN (Public Network) 1- 7 G3 FAX 2-1 T-FAX (transmitting FAX) 2-2 T-ADP (transmitting protocol converter) 2-3 R-ADP (receiving protocol converter) 2-4 R-FAX (receiving FAX) 3-1 T-FAX (transmitting-side FAX) 3-2 T-ADP (transmitting-side protocol converter) 3-3 R-ADP (receiving-side protocol converter) 3-4 R-FAX (receiving-side FAX) 6- 1 Judgment circuit 6-2 EOP / DCN transmission unit 6-3 Data communication release request transmission unit 6-4 Timer control unit 7-1 Judgment circuit 7-2 DCN delivery confirmation signal transmission unit 7-3 Data communication release request transmission unit -4 timer control unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/32 H04L 13/00 307A (72) Inventor Mitsuru Murata 2-10-1, Toranomon, Minato-ku, Tokyo F-term in NTT Mobile Communication Network Co., Ltd. (reference) 5K067 AA23 AA26 BB04 DD11 DD52 EE02 EE10 EE32 HH05

Claims (10)

[Claims] 1. A protocol conversion device which is built in or connected to a mobile station, connected to a network side via a radio base station, and transmits / receives a data signal via a radio section, wherein a second protocol connected to the network side is provided. The conversion device receives a line disconnection signal from the first protocol conversion device built in or connected to the mobile station, and, when transmitting all of the transmitted data signals to the destination communication device, A protocol conversion device, comprising: means for transmitting an acknowledgment signal for the line disconnection signal to the first protocol conversion device. 2. The means for activating a timer after transmitting the acknowledgment signal, receiving a request to release data communication from the first protocol conversion apparatus during activation of the timer, 2. The protocol conversion device according to claim 1, further comprising means for terminating communication when the timer has timed out. 3. The second protocol converter according to claim 2, wherein the second protocol converter itself transmits a data communication release request to the first protocol converter when terminating the communication. Protocol converter. 4. The protocol conversion device according to claim 1, wherein the second protocol conversion device converts the data signal into a facsimile communication protocol used on a wired line. 5. A protocol conversion device built in or connected to a mobile station, connected to a network through a radio base station, and transmitting and receiving a data signal through a radio section, comprising: The protocol conversion device comprises: means for transmitting a line disconnection signal after transmitting all the data signals; and means for receiving a delivery confirmation signal for the line disconnection signal from a second protocol conversion device connected to the network. A protocol conversion device, comprising: 6. The first protocol conversion device, means for starting a timer after transmitting the line disconnection signal, and receiving the acknowledgment signal from the second protocol conversion device while the timer is running, or 6. The protocol conversion device according to claim 5, further comprising: means for terminating the communication when the timer has timed out. 7. When ending communication, the first protocol conversion device sends a request to release data communication to the second protocol conversion device.
The protocol converter according to claim 6, wherein the protocol converter is transmitted to the protocol converter. 8. The protocol conversion device according to claim 5, wherein the first protocol conversion device converts the data signal into a facsimile communication protocol dedicated to a wireless section. 9. A first protocol conversion device built in or connected to a mobile station, a first communication device connected to the first protocol conversion device, and a data signal transmitted from the first communication device. The mobile station transmitting to the wireless section,
The data signal is sent to a second protocol conversion device connected to the network side via a wireless base station, and the data signal is further sent to a second communication device of a transmission destination via the second protocol conversion device. In the communication system, wherein the data signal transmitted and received from the first communication device is received by the second communication device, the first protocol conversion device transmits a line disconnection signal after transmitting all the data signals. Means for transmitting a line disconnection signal; means for starting a timer after transmitting the line disconnection signal; and receiving a delivery confirmation signal for the line disconnection signal from the second protocol converter during the timer activation, or the timer is a timer. Means for transmitting a data communication release request to the second protocol conversion device when the communication is out of communication, and terminating the communication. Means for receiving the line disconnection signal and transmitting the acknowledgment signal to the first protocol conversion device when all the data signals have been transmitted to the second communication device; Means for activating a timer after transmitting the acknowledgment signal; and receiving a signal for releasing data communication from the first protocol conversion device during activation of the timer, or when the timer has timed out. Means for transmitting a data communication release request to the first protocol converter and terminating the communication. 10. The first communication device is a portable facsimile terminal, the second communication device is a facsimile device connected to a wired line, and the first protocol conversion device is the portable facsimile terminal. Means for converting the data signal sent from the wireless communication section into a facsimile communication protocol dedicated to a wireless section, wherein the second protocol converter uses the data signal sent via the wireless section over a wired line. 10. The communication system according to claim 9, further comprising means for converting a communication protocol.