Facsimile apparatus.

Description: TECHNICAL FIELD [Detailed description of the invention]

[Industrial application field] The present invention relates to a facsimile machine, particularly a facsimile machine connected to a digital network in a communication network in which a digital network and an analog network are connected.

[Conventional technology] ISDN is a communication network that provides a wide variety of services such as telephone, data, and fax communication services, and information such as voice and image data is communicated via an information channel called B channel with a digital signal of 64 Kbps. Signaling information such as link control and call control used for communication with the network is transferred on the 16Kbps D channel. The public switched telephone network (PSTN) is currently widely used, but will be replaced by ISDN in the future. In the transitional period of replacement, ISDN and PSTN will coexist for a long period of time, and inter-network connection between the two networks will also be made. In the modulation / demodulation of G3 fax, the CCITT V.21 300bps modem is used for the procedure signal and the CCITT V.29 9600bps modem is used for the image signal, and the bandwidth used is 300HZ to 3.3KHZ. The ISDN fax machine uses the transmission analog signals of both modems to CCITT in the intercommunication with the G3 fax machine in the network connection between the ISDN and the PSTN. G.711 μ-law or A-law code is used to convert to a digital signal for transmission, and the received digital signal is converted to an analog signal with the code. Then, the transmitted / received digital signal is transferred to or from the telephone network via the B channel of ISDN. ISDN bearer services are defined in CCITT Recommendation I.211 and are classified as Voice, 3.12HZ Audio, 64KHZ Unrestricted Digital. 24. Voice is a telephone signal, 3.1KHZ audio is a data signal in the 3.1KHZ band such as G3 Faxis Milli, and 64KHZ unrestricted digital is a digital signal such as G4 Faxis Milli. As described above, ISDN recognizes whether the information flowing through the network is the voice of a telephone or the image data of a fax machine. The ISDN terminal executes the incoming call procedure as shown in Fig. 3. The network indicates to the incoming terminal by SET UP message the classification of voice signal, 3.1KHZ audio signal, or 64KHZ unrestricted digital signal as transmission capability. The receiving terminal checks the above-mentioned transmission ability and decides whether or not to respond. On the other hand, in the telephone network, only the end-to-end path is connected according to the telephone number requested by the calling terminal, and it is recognized whether the information flowing in the network is a voice signal or a faximiri image signal. Can not. Therefore, in the inter-network connection between the telephone network and ISDN, there is no distinction between voice and 3.1KHZ audio when making a call from the telephone network and receiving an incoming call to ISDN. This means that the ISDN fax machine cannot recognize whether the calling terminal is a telephone or a fax machine.

[Problems to be solved by the invention] As described above, when an incoming call is received from a public telephone network telephone or G3 fax, it is unknown whether the ISDN terminal is a call from the telephone or a fax, so should the incoming terminal answer with a fax signal? There was a problem that it was not possible to determine whether to notify the operator of the incoming call. The present invention provides a facsimile apparatus that eliminates the above-mentioned conventional drawbacks and appropriately performs facsimile communication regardless of whether an incoming call is received from a terminal of a digital network or an analog network via a digital network.

[Means to solve problems] In order to solve this problem, the facsimile apparatus of the present invention indicates the type of incoming call from the digital network in the communication network in which the digital network and the analog network are connected, and in the facsimile apparatus connected to the digital network. A receiving means for receiving an incoming message containing information, a digital facsimile communication means for communicating digital data via the digital network, and data received as digital voice data from the digital network are converted into analog signals. Whether or not the incoming call is from the analog network via the digital network based on the analog facsimile communication means that converts the analog signal into digital voice data and transmits it to the digital network and the incoming message received by the receiving means. And the identification means for detecting a signal related to analog facsimile communication from the data received as digital voice data from the digital network in the case of an incoming call from the analog network via the digital network, and the identification. It is characterized by comprising a control means for selectively starting a communication operation by the digital facsimile communication means or a communication operation by the analog facsimile communication means according to the identification by the means and the signal detection by the signal detection means.

[Example] FIG. 1 shows a block configuration diagram of a fax machine of an embodiment. 1 is a reader unit that reads documents, 2 is a main control unit that controls the entire system, 3 is a printer unit that prints, 4 is an ISDN interface unit that controls transmission / reception with ISDN, and 5 is a G4 fax B channel protocol. The G4CCU section that executes, 6 is the G3CCU section that executes the T.30 protocol of the G3 fax, 7 is the modem section that modifies and demolishes the T.30 protocol signal and the image signal of the G3 fax, and the CNG detection section 7a that detects the CNG signal. Be prepared. 8 converts between analog and digital signals. G.711 coordination section, 9 is the handset section of the telephone, 10 is the G.711 coordination section that converts audio signals and digital signals, 11 is the ISDN line, and 12 is the automatic reception switch. First, in the above configuration, the operation at the time of transmission will be described. The image data read by the reader unit 1 is transferred to the G4 CCU unit 5 in the G4 mode and to the G3 CCU unit 6 in the G3 mode. In the G4CCU section 5, the B channel protocol is added, and the B channel signal B is added to the ISDN interface section 4.₁Transferred as. In G3CCU section 6, protocol T.30 for G3 fax is added, modulated by modem section 7, converted to PCM signal by codec section 8, and B channel signal B is added to ISDN interface section 4.₂Transferred as. In the hand set unit 9, the voice is converted into an electric signal, and the code unit 10 converts the B channel signal B.₃Is transferred to the ISDN interface section 4. The ISDN interface section 4 includes ISDN D-channel protocol layer 1 (CCUTT recommendation I.430), layer 2 (CCUTT recommendation I.441), layer 3 (CCUTT recommendation I.451), and B-channel protocol layer 1 (CCUTT recommendation I.451). Follow the procedure according to .430). D-channel protocol layer 1 and B-channel protocol layer 1 are physical electrical rules and channel multiplexing rules, and D-channel protocol layer 2 is a link control procedure rule with the network, and the D-channel protocol. Layer 3 defines a call control procedure for connecting to a communication partner. The ISDN interface unit 4 connects with a communication partner by the D channel protocol, and after the connection is completed, the information from the G4CCU unit 5, the G3CCU unit 6 or the handset unit 9 is transmitted from the ISDN line 11 via the B channel. Next, the case of an incoming call will be described. The signal received from the ISDN line 11 is separated into a D channel and a B channel by the ISDN interface unit 4, and the B channel information is converted into an analog signal by the G4 CCU unit 5 or the coding unit 8, and the modem unit 7 and the CNG detection unit 7a It is converted into an analog signal by the B3CCU unit 6 or the coordination unit 10 and transferred to the handset unit 9 via the above. Then, the image signals from the G4 CCU unit 5 and the G3 CCU unit 6 are printed and output to the printer unit 3 by the main control unit 2. FIG. 2 shows a flowchart of an incoming call operation of the fax machine of the present embodiment. First, when there is an incoming call from the network in step S20, the ISDN call control procedure is executed by the ISDN interface unit 4 in FIG. In step S21, one of voice, 3.1KHZ audio, and 64KHZ unrestricted digital is recognized by the transmission capability information element in the SET UP message in Fig. 3. In step S22, whether or not the call is received from the telephone network is identified by the progress identifier information element in the SET UP message. The operations of steps S21 and S22 are also executed by the ISDN interface unit 4 of FIG. If there is no incoming call from the telephone network, proceed to step S27 to communicate with the ISDN terminal. If there is an incoming call from the telephone network, the CNG detection unit 7a in FIG. 1 detects the CNG signal in step S23, and the detection result is notified to the G3CCU unit 6 and further to the main control unit 2. Here, the CNG signal will be described. CCITT Recommendation T.30 specifies the G2 and G3 fax machine protocols for telephone networks. The communication procedure of the G3 fax machine is shown in Fig. 4. In T.30, the CNG signal is defined as follows. (1) The calling station of the non-voice terminal first transmits the CNG signal. (2) Required for automatic calling terminals, option for manual terminals. (3) Sine wave with frequency 1100 ± 38HZ (4) On for 0.5 seconds, off for 3 seconds. In step S23, this CNG signal is detected, for example, as follows. <Detection of sine wave with frequency 1100HZ> There are the following two methods for detecting the frequency of 1100 HZ, which is the condition of (3) above. One is to compare the analog waveform of the input signal with the reference potential by a comparator, differentiate the output from this comparator by a differentiating circuit, count the interval between the differential pulses when the input signal crosses the reference potential, and calculate the frequency. To detect. The other is to detect 1100HZ by the PLL circuit. <Signal width detection> As a method of detecting on for 0.5 seconds and off for 3 seconds, which is the condition of (4) above, when the frequency is detected by the differential pulse, the time during which the differential pulse is input is measured within a predetermined interval. On the other hand, in the case of a PLL circuit, it is possible by measuring the time length of the output waveform. In the above, on for 0.5 seconds was detected, but the following 3 seconds can be turned off in the same way. The conditions for detecting CNG are the above two conditions (3) and (4), but in reality, it is sufficient to detect only the frequency of (3). If a CNG signal is detected, the process proceeds to step S25, the communication partner is determined to be a G3 fax machine, and communication is performed according to the G3 communication procedure shown in FIG. If no CNG signal is detected, the process proceeds to step S24, and the main control unit 2 in Fig. 1 determines whether the automatic reception switch 12 is in the ON state. In the automatic reception mode, the process proceeds to step S25 to perform G3 communication. If it is not in the automatic reception mode, proceed to step S26 to notify the operator of the incoming call. In this embodiment, the fax machine connected to the telephone network is G3, but the fax machine of the telephone network may be G1 or G2 fax machine. This is because the fax machine also transmits a CNG signal in the same manner as the G3 fax machine. Further, the determination of the incoming data by detecting the CNG signal of this embodiment is also effective in the communication between G3 fax machines. Further, the CNG detection unit is placed in the modem unit for the purpose of simplifying the circuit, and the present invention is not limited to this. As described above, when there is an incoming call from the telephone network, the CNG signal is detected, and if it is detected, it is determined that the communication partner is the fax machine of the telephone network, so that the communication between the telephone and the fax machine is performed. This has the effect of reducing communication failures due to mode mismatch.

[Effect of the invention] INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a facsimile apparatus that appropriately performs facsimile communication regardless of whether an incoming call is received from a terminal of either a digital network or an analog network via a digital network. That is, digital facsimile communication can be performed for incoming calls from the digital network, and analog facsimile communication can be appropriately performed for incoming calls from the analog network via the digital network without the need for manual operation by the operator. Can be done.

[Simple explanation of drawings]

FIG. 1 is a block configuration diagram of the fax machine of this embodiment. FIG. 2 is a flowchart showing an incoming call operation of the fax machine of this embodiment. Figure 3 shows the ISDN incoming procedure, FIG. 4 is a diagram showing a communication procedure of G3 fax machine. In the figure, 1 ...... reader part, 2 ...... main control part, 3 ...... printer part, 4 ...... ISDN interface part, 5 .... .. G4CCU part, 6 ...... G3CCU part, 7 ...... Modem part, 7a ...... CNG detection part, 8 ...... Coordination part, 9 ... ... Handset part, 10 ... Coordination part, 11 ... ISDN line, 12 ... Automatic reception interface.