JP2007043419A - Communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continue communication procedures of facsimile communication even if the facsimile machine executes facsimile communication via an IP network with an echo canceller function. <P>SOLUTION: When a phase inversion circuit 12 of a main control section 1 of the facsimile machine 20 detects the phase inversion of a 2,100 Hz signal (YES in S19), the main control section 1 determines that an ANSam signal in an ITU-T recommendation V.34 mode (S20) is detected, but when the circuit 12 detects no phase inversion (NO in S19), the main control section 1 determines that a CED signal of facsimile communication (S21) is detected. When the main control section 1 determines that the CED signal is detected, the main control section 1 responds to a DIS signal transmitted from an opposite facsimile machine in succession to the CED signal (S32 to S43), and when the main control section 1 determines that the detection of the ANSam signal (NO in S34) is detected, the main control section 1 responds to a succeeding DIS signal (S32 to S35) without responding to the DIS signal transmitted from the opposite facsimile machine in succession to the ANSam signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a facsimile apparatus for performing facsimile communication with a counterpart facsimile apparatus via, for example, an IP network.

  As a fax modem for transmitting a facsimile image signal via a public telephone line, a conventional ITU-T recommendation V.16 having a maximum data rate of 14.4 kbps. ITU-T Recommendation V.4, called the “Super G3”, which is faster than a fax modem in 17 communication mode and has a maximum data rate of 33.6 kbps. A fax modem of 34 communication mode has been put into practical use.

  On the other hand, recently, not only data communication such as the Internet but also telephone communication and facsimile communication have been performed using a so-called IP network, which is a communication network using communication procedures of the Internet protocol. That is, facsimile communication is performed between a pair of opposing facsimile apparatuses via an IP network 50 that performs communication using, for example, an RTP, UDP, or IP protocol. FIG. 2 is a line configuration diagram when is connected to the facsimile machine 20A of the other party via the IP network 50 and the public telephone network 30. FIG.

  In FIG. 2, the NCU (Network Control Unit) 11 of the facsimile machine 20 </ b> A of the other party is connected to the NCU 41 of the media gateway apparatus 40 via the public telephone network 30. The media gateway device 40 is a device that performs mutual conversion between an analog signal and a digital signal. The media gateway device 40 is a VoIP terminal adapter device (also referred to as a VoIP gateway device) via a router device 51, an IP network 50, and a router device 52. 60. Here, the VoIP terminal adapter device 60 is also a device that performs mutual conversion between an analog signal and a digital signal, like the media gateway device 40. Furthermore, the NCU 51 of the VoIP terminal adapter device 60 and the NCU 11A of the counterpart facsimile machine 20A are connected. That is, facsimile communication via the public telephone network 30 and the IP network 50 is performed by a pair of opposing facsimile apparatuses 20 and 20A, and signal conversion is performed by the two gateway apparatuses 40 and 60.

  V. In the 34 mode communication, for full-duplex communication, an exchange such as a gateway device is connected to the V.C. When an ANSam signal used in 34-mode communication is detected, the echo canceller may be turned off. The echo canceller remains off and When communication in the 17th mode or lower is performed, the termination flag of the FSK signal (CFR) sent by the own device is erroneously recognized as the FSK signal sent from the sending side terminal at the time of high / low speed identification of the receiving side terminal. There is a problem that a low-speed standby occurs, and even when an original high-speed signal is received, the FSK signal standby timeout occurs, resulting in a communication error.

  In order to solve the above problems, for example, in Patent Document 1, V. In order to provide a facsimile machine capable of performing 34-mode communication without any trouble, the facsimile machine is ITU-T Recommendation V.3. A fax modem 10 having a communication function of 34 communication modes is provided. Here, when making a call, the main control unit 1 checks the facsimile number of the other party with reference to the transmission side IP network check table, and when the call is made via the IP network, makes a call to the other party and sends an ANSam signal. When a DIS signal is detected after detecting the signal, the next DIS signal is detected without responding to the detected DIS signal, and a DCS signal as a response signal is transmitted. Therefore, even if an IP network switch or the like turns off the echo canceller by the ANSam signal, a predetermined silent time is generated, so that the echo canceller can be restored and image communication such as facsimile communication in the normal G3 communication mode is possible. Become.

Japanese Patent Application Laid-Open No. 2003-259099.

  The echo canceller described above detects the 2100 Hz signal in the facsimile communication signal, detects the presence or absence of phase inversion, and switches on / off the echo canceller function. The 2100 Hz signal is used for the CED signal and the ANSam signal. However, the transmission of this signal does not always match the protocol applied in actual facsimile communication, and the following troubles occur frequently. Yes.

  A facsimile apparatus 20A having a G3 mode facsimile apparatus 20 in which the transmission side performs half-duplex data communication and a so-called super G3 mode in which the reception side performs full-duplex data communication (that is, having an ITU-T recommendation V.34 mode). If the receiving side facsimile apparatus 20A sends out the ANSam signal, the echo canceller function provided in the IP network 50 becomes invalid based on the 2100 Hz signal, and the transmitting side facsimile apparatus 20 cannot demodulate the signal. However, the communication procedure of facsimile communication is interrupted.

  The object of the present invention is to solve the above problems and provide a facsimile apparatus capable of properly continuing the communication procedure of facsimile communication even when facsimile communication is performed via an IP network having an echo canceller function. There is to do.

A facsimile apparatus according to the present invention is a facsimile apparatus that performs facsimile communication with a destination facsimile apparatus via an IP network.
A phase inversion circuit that receives a 2100 Hz signal from the facsimile machine of the other party and detects whether the received 2100 Hz signal has undergone phase inversion;
When the phase inversion of the 2100 Hz signal is detected by the phase inversion circuit, the ITU-T recommendation V. Control means for determining that a CED signal for facsimile communication is detected when it is determined that a 34-mode ANSam signal has been detected but phase inversion is not detected.

  In the facsimile apparatus, when the control means determines that the CED signal has been detected, the control means responds to a DIS signal sent from the counterpart facsimile apparatus following the CED signal.

  Further, in the facsimile apparatus, when the control means determines that the ANSam signal has been detected, the control means does not respond to the DIS signal sent from the facsimile apparatus of the other party following the ANSam signal, and does not respond to the next DIS signal. It is characterized by responding.

  Therefore, according to the facsimile apparatus of the present invention, when the phase inversion of the 2100 Hz signal is detected by the phase inversion circuit, the ITU-T Recommendation V. Control means for determining that a CED signal for facsimile communication has been detected when phase inversion is not detected while determining that an ANSam signal in 34 mode has been detected. In the facsimile apparatus, the control means comprises the CED When it is determined that a signal has been detected, the control means responds to the DIS signal sent from the facsimile machine of the other party following the CED signal, and when the control means determines that the ANSam signal has been detected, Subsequently, it responds to the next DIS signal without responding to the DIS signal sent from the facsimile machine of the other party. Therefore, the echo canceller function that is turned off by the first ANSam signal in the IP network exchange is turned on again, and in response to the second DIS signal, the transmitting facsimile apparatus cannot demodulate the signal. The problem that the communication procedure of facsimile communication is interrupted can be solved, and the communication procedure of facsimile communication can be continued properly.

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

<Embodiment>
FIG. 1 is a block diagram showing a configuration of a facsimile machine 20 including a facsimile modem 10 having a phase inversion circuit 12 for a 2100 Hz signal according to an embodiment of the present invention. Also in this embodiment, the facsimile apparatus 20 is assumed to be connected to the facsimile apparatus 20A of the other party via the IP network 50 and the public telephone network 30 as shown in FIG. As is well known, facsimile communication may be performed by connecting to the facsimile machine 20A of the other party only through the telephone network 30.

  The facsimile apparatus 20 of this embodiment includes a phase inversion circuit 12 in the facsimile modem 10 that receives a 2100 Hz signal from the counterpart facsimile apparatus 20A and detects whether or not the received 2100 Hz signal has undergone phase inversion. 20 detects the phase inversion of the 2100 Hz signal by the phase inversion circuit 12 (YES in step S19 in FIG. 4), the ITU-T recommendation V.20. It is determined that the 34 mode ANSam signal has been detected (step S20). On the other hand, if the phase inversion is not detected (NO in step S19), it is determined that the CED signal for facsimile communication has been detected (step S21). When the main control unit 1 determines that the CED signal is detected, the main control unit 1 responds to the DIS signal sent from the facsimile machine of the other party following the CED signal (steps S32 to S43), and the ANSam. When it is determined that a signal has been detected (NO in step S34), it responds to the next DIS signal (steps S32-S35) without responding to the DIS signal sent from the counterpart facsimile machine following the ANSam signal. It is characterized by.

  In FIG. 1, a facsimile apparatus 20 includes a facsimile modem 10 having a conventional G3 system facsimile communication function and a phase inversion circuit 12 for a 2100 Hz signal. The main control unit 1 is specifically composed of a CPU, and is connected to the following hardware units via the bus 13 to control them, and executes various software functions to be described later. The image reading unit 2 reads a document with a scanner using a CCD or the like, and outputs dot image data converted into black and white binary. The image recording unit 3 is an electrophotographic printer or the like, and prints out image data received from another facsimile apparatus by facsimile communication as a hard copy and records it. The display unit 4 is a display device such as a liquid crystal display device (LCD) or a CRT display, and displays the operation state of the facsimile device 20 and displays image data of a document to be transmitted and received image data. .

  The operation unit 5 includes character keys necessary for operating the facsimile apparatus 20, a dial keypad, a speed dial key, a one-touch dial key, various function keys, and the like. In addition, you may comprise so that a part or all of the various keys of this operation part 5 may be substituted by making the above-mentioned display part 4 into a touch panel system.

  The ROM 6 stores in advance various software programs that are necessary for the operation of the facsimile apparatus 20 and are executed by the main control unit 1. Here, the programs are at least used in the facsimile transmission processing of FIGS. 3 to 5. Includes programs. The RAM 7 is configured by SRAM, flash memory, or the like, and is used as a working area for the main control unit 1 to store temporary data generated when the program is executed. When a flash memory is used as the RAM 7, the contents of the data are not lost even when the power is cut off due to a power failure, movement of the device, or the like. The image memory 8 is composed of a DRAM or the like, and stores image data to be transmitted or received image data. Note that the RAM 7 and the image memory 8 may be constituted by a hard disk memory.

  The fax modem 10 is a modem connected to the public telephone line L and having a function of a fax modem for normal facsimile communication. The fax modem 10 demodulates data of outgoing telephone number information received as an FSK signal and sends it to the main control unit 1. Output. Further, the facsimile modem 10 includes the phase inversion circuit 12 for the 2100 Hz signal as described above. The phase inversion detection circuit 12 detects the 2100 Hz signal out of the received signal by band filtering using a band pass filter, and then synchronously reproduces the phase inversion of the signal based on the previously received 2100 Hz. Detection is performed by comparing the phase of the generated 2100 Hz signal with the reference signal.

  The NCU 11 is a hardware circuit that performs closing and opening operations such as a DC loop of the analog public telephone line L and has an automatic dial function, and connects the fax modem 10 to the public telephone line L as necessary. Here, the NCU 11 detects the ID receiving terminal activation signal and the normal telephone call signal in the outgoing telephone number notification service, and transmits the primary response signal and the secondary response signal in the outgoing telephone number notification service as necessary. can do. The NCU 11 may be connected to a baseband transmission type digital line (for example, an ISDN line) via a predetermined terminal adapter and a DSU (Subscriber Line Termination Unit: Digital Service Unit).

  The facsimile apparatus 20 of the present embodiment configured as described above has a modem control function based on the ringing tone of an IP telephone in addition to a normal facsimile communication function such as the G3 system. In the facsimile communication function, the dot image data read by the image reading unit 2 is encoded by software in accordance with an encoding method such as MH, MR, or MMR defined in the facsimile communication standard, and then the counterpart facsimile machine On the other hand, the encoded data received from the facsimile machine of the other party is also decoded into image data by software and output from the image recording unit 3 as a hard copy. The image memory 8 stores the image data as necessary, and conversely outputs the stored image data as necessary.

  Furthermore, a communication procedure in the V34 mode capable of data communication such as facsimile communication at high speed will be described. When data communication is performed with a communication terminal device such as a facsimile device, a modem device conforming to the communication procedure of the recommended V17 mode of the ITU-T (International Telecommunication Union-Telecommunication Standardization Sector), for example, is used. Then, it is performed in accordance with the procedure defined in the recommendation T30, which is also a G3 standard facsimile communication procedure. In addition, an ultra-high speed communication procedure (hereinafter referred to as V34 mode communication procedure) with a maximum transmission rate of 33.6 kbps conforming to the recommendation V34 has been put into practical use. During communication execution, it is possible to specify the communication speed according to the current line status, specifically S / N (signal to noise power ratio) and bandwidth on the receiving side. In this way, the communication speed is changed so that transmission is performed at the communication speed specified on the receiving side. When data communication is performed using the communication procedure in the V34 mode, the actual communication speed is determined by performing the pre-procedure in the same recommended V8 communication procedure.

  FIG. 3 is a flowchart showing a facsimile transmission process executed by the main control unit 1 of the facsimile apparatus 20 of FIG.

  In step S1 of FIG. 3, first, a calling process for calling the counterpart facsimile machine 20A is executed, and a tone detection process for detecting a tone signal from the counterpart facsimile machine 20A or the network in step S2. In step S3, it is determined whether or not the tone detection result has already been detected. If YES, the process proceeds to step S4. If NO, the process proceeds to step S5. In step S4, after the facsimile transmission process of FIG. 4 is executed, the line is opened in step S6 and the facsimile transmission process ends. On the other hand, in step S5, after waiting for redialing, the line is opened in step S6 and the facsimile transmission process is terminated.

  FIG. 4 is a flowchart showing a tone detection process (S3) which is a subroutine of FIG.

  In step S11 of FIG. 4, first, a phase inversion detection circuit initialization process for initializing the phase inversion detection circuit 12 is executed. In step S12, a tone detection initialization process for initializing parameters for tone detection is executed. In S13, a monitoring timer initialization process for initializing the monitoring timer is executed, and the process proceeds to Step S14. In step S14, it is determined whether a tone signal is detected. If NO, the process proceeds to step S15. If YES, the process proceeds to step S17. In step S15, for example, it is determined whether or not the 60-second T0 timer has expired. If NO, the process returns to step S14. If YES, the process proceeds to step S16. In step S16, after waiting for redialing, the process returns to the original main routine.

  In step S17, it is determined whether or not a busy tone signal is detected. If YES, the process proceeds to step S17. If NO, the process proceeds to step S18. In step S18, it is determined whether or not a 2100 Hz signal is detected. If NO, the process returns to step S14. If YES, the process proceeds to step S19. In step S19, it is determined whether or not phase inversion is detected by the phase inversion detection circuit 12. If YES, the process proceeds to step S20. If NO, the process proceeds to step S21. In step S20, after determining that the ANSam signal has been detected, the process returns to the original main routine. On the other hand, in step S21, after determining that the CED signal has been detected, the process returns to the original main routine.

  FIG. 5 is a flowchart showing a facsimile transmission process (S4) which is a subroutine of FIG.

  In step S31 of FIG. 5, first, various parameter initialization processing is executed, and the process proceeds to step S32. In step S31, the initial value of the DIS1 miss flag DF is set based on the tone detection result in the process of FIG. 4, and when the CED signal is detected, the DIS1 miss flag DF is set to 1, while ANSam When the signal is detected, the DIS miss flag DF is reset to 0. In step S32, it is determined whether a DIS signal has been detected. If YES, the process proceeds to step S34. If NO, the process proceeds to step S33. In step S33, it is determined whether or not a T1 time (a so-called T1 timer, T1 is 35 to 45 seconds) has elapsed. If YES, the process returns to the original routine. Return to S32.

  In step S34, it is determined whether or not the tone detection result is CED signal detection. If YES, the process proceeds to step S37, and if NO, the process proceeds to step S35. In step S35, it is determined whether the DIS signal has been missed once flag DF is 1. It is determined whether or not the flag has been set. If YES, the process proceeds to step S37. If NO, the process proceeds to step S36. In step S36, the DIS signal missed once flag DF is set to 1, and then the process returns to step S32. After step S37, a normal facsimile communication procedure is executed. In step S37, a DCS signal is transmitted. In step S38, a TCF signal is transmitted. In step S39, a CFR signal is received. In step S40, image data is transmitted. Send it out. Further, an EOP signal is transmitted in step S41, an MCF signal is received in step S42, a DCN signal is transmitted in step S43, and the process returns to the original routine.

  As described above, when the main control unit 1 of the facsimile apparatus 20 detects the phase inversion of the 2100 Hz signal by the phase inversion circuit 12 (YES in step S19 in FIG. 4). ITU-T recommendation V. It is determined that the 34 mode ANSam signal has been detected (step S20). On the other hand, if the phase inversion is not detected (NO in step S19), it is determined that the CED signal for facsimile communication has been detected (step S21). When the main control unit 1 determines that the CED signal is detected, the main control unit 1 responds to the DIS signal sent from the facsimile machine of the other party following the CED signal (steps S32 to S43), and the ANSam. When it is determined that a signal has been detected (NO in step S34), it responds to the next DIS signal (steps S32-S35) without responding to the DIS signal sent from the counterpart facsimile machine following the ANSam signal. Therefore, the echo canceller function that is turned off by the first ANSam signal in the switch of the IP network 50 is turned on again, and in response to the second DIS signal, the transmitting facsimile apparatus 20 can demodulate the signal. Therefore, the problem that the communication procedure of facsimile communication is interrupted can be solved, and the communication procedure of facsimile communication can be continued properly.

<Modification>
In the above embodiment, an example of the facsimile apparatus 20 has been described. However, the present invention is not limited to this, and for example, a telephone connected to a public network such as an IP telephone network, a public telephone network, or a public digital circuit network, The present invention can be applied to communication terminal devices including data communication devices.

  As described in detail above, according to the facsimile apparatus of the present invention, when the phase inversion of the 2100 Hz signal is detected by the phase inversion circuit, the ITU-T recommendation V. Control means for determining that a CED signal for facsimile communication has been detected when phase inversion is not detected while determining that an ANSam signal in 34 mode has been detected. In the facsimile apparatus, the control means comprises the CED When it is determined that a signal has been detected, the control means responds to the DIS signal sent from the facsimile machine of the other party following the CED signal, and when the control means determines that the ANSam signal has been detected, Subsequently, it responds to the next DIS signal without responding to the DIS signal sent from the facsimile machine of the other party. Therefore, the echo canceller function that is turned off by the first ANSam signal in the IP network exchange is turned on again, and in response to the second DIS signal, the transmitting facsimile apparatus cannot demodulate the signal. The problem that the communication procedure of facsimile communication is interrupted can be solved, and the communication procedure of facsimile communication can be continued properly.

1 is a block diagram illustrating a configuration of a facsimile machine 20 including a facsimile modem 10 having a 2100 Hz signal phase inverting circuit 12 according to an embodiment of the present invention. FIG. 2 is a line configuration diagram when the facsimile apparatus 20 of FIG. 1 is connected to a destination facsimile apparatus 20A via an IP network 50 and a public telephone network 30. 3 is a flowchart showing a facsimile transmission process executed by a main control unit 1 of the facsimile apparatus 20 of FIG. It is a flowchart which shows the tone detection process (S3) which is a subroutine of FIG. It is a flowchart which shows the facsimile transmission process (S4) which is a subroutine of FIG.

Explanation of symbols

1 ... main control part,
2. Image reading unit,
3 ... image recording unit,
4 ... display part,
5 ... operation part,
6 ... ROM,
7 ... RAM,
8 ... Image memory,
10. Fax modem,
11, 11A ... NCU,
12: Phase inversion detection circuit,
13 ... Bus
20, 20A ... facsimile machine,
30 ... public telephone network,
40. Media gateway device,
41 ... NCU,
50 ... IP network,
51, 52 ... router device,
60 ... VoIP terminal adapter device,
61 ... NCU,
L: Public telephone line.

Claims (3)

In a facsimile machine that performs facsimile communication with the other party's facsimile machine via the IP network,
A phase inversion circuit that receives a 2100 Hz signal from the facsimile machine of the other party and detects whether the received 2100 Hz signal has undergone phase inversion;
When the phase inversion of the 2100 Hz signal is detected by the phase inversion circuit, the ITU-T recommendation V. A facsimile apparatus comprising: control means for determining that a 34 mode ANSam signal has been detected, but not detecting phase inversion, and determining that a CED signal for facsimile communication has been detected.   2. A facsimile apparatus according to claim 1, wherein said control means responds to a DIS signal sent from a facsimile apparatus of the other party following said CED signal when determining that said CED signal has been detected. When the control means determines that the ANSam signal has been detected, the control means does not respond to the DIS signal sent from the facsimile machine of the other party following the ANSam signal, but responds to the next DIS signal. The facsimile apparatus according to claim 1 or 2.

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