JP6375786B2 - Communication device - Google Patents

Description

  The present invention relates to a communication apparatus that performs communication using a telephone line.

  Conventionally, there are communication apparatuses that perform communication using a telephone line.

  In this type of communication apparatus, a configuration has been proposed in which power is supplied to the modem unit only when a telephone line is connected to the modem unit. In the communication device of Patent Document 1, a line voltage detection circuit for detecting the voltage of the telephone line is provided, and the telephone line is connected to the modem unit, and the voltage on the telephone line is detected by the line voltage detection circuit. The power source is supplied to the modem unit. When the telephone line is not connected to the modem unit and the voltage on the telephone line is not detected by the line voltage detection circuit, the supply of power to the modem unit is stopped.

JP 2000-341430 A

  However, in the communication device of Patent Document 1, it is necessary to supply power separately to the line voltage detection circuit in order to constantly monitor whether or not the telephone line is connected to the modem unit, thereby further reducing power consumption. It is desired.

  An object of the present invention is that when a ring signal is transmitted from the other party even if the modem part of the communication device is in a power-off state without always monitoring whether or not the telephone line is connected to the modem part. It is another object of the present invention to provide a communication apparatus that can automatically start the modem unit and does not need to always start the modem unit.

  In order to achieve the above object, a communication apparatus according to one aspect of the present invention includes a line connection terminal having two terminals connectable to a telephone line, one of the line connection terminals, and the first connection line. Connected to the other terminal of the line connection terminal via the second connection line, a first electrode and a second electrode, and the first electrode is connected to the first connection line. 1 capacitor, a third electrode having a third electrode and a fourth electrode, the third electrode being connected to the second connection line, and the second electrode passing through the first capacitor among the voltages applied to the telephone line A DC voltage converter that converts a potential difference between the AC voltage output from the AC voltage output from the fourth electrode through the second capacitor among the voltages applied to the telephone line to a DC voltage, Modem by DC voltage converted by voltage converter There is started.

  In a state where a telephone line is connected to the line connection terminal of the communication device, a DC voltage of about 48V is constantly applied. In addition, an AC signal is superimposed on the DC voltage in an electrical signal such as a ring signal sent from the other party to the communication device through a telephone line. The first capacitor and the second capacitor do not pass the DC voltage component that is always applied, but only allow the AC voltage component of the electrical signal transmitted from the counterpart side to pass. Then, the potential difference of the passed AC voltage component is converted into a DC voltage, and the DC voltage is supplied to the modem unit.

  Thereby, in the communication device of the present invention, even when the modem unit of the communication device is in a power-off state, the modem unit is automatically activated when a ring signal is transmitted from the partner side. Therefore, it is not necessary to always activate the modem unit.

  The communication apparatus is further connected to a commercial power source and provided between a power supply unit that outputs a DC voltage and a modem unit and the power supply unit, and connects or disconnects the modem unit and the power supply unit. A switch unit, and the modem unit outputs a predetermined signal in response to the supply of the DC voltage from the DC voltage conversion unit, and the switch unit connects the modem unit and the power supply unit by the predetermined signal. May be.

  The power supply unit and the modem unit are connected, and the voltage of the power supply unit is supplied to the modem unit. As a result, a stable voltage from the power supply unit can be supplied to the modem unit, and the modem unit can be operated stably.

  The communication apparatus further includes a control unit, the control unit is connected to the power supply unit via the switch unit, and the modem unit outputs a predetermined signal in response to the supply of the DC voltage from the DC voltage conversion unit. The switch unit may receive a predetermined signal and connect between the control unit and the power supply unit.

  Before the AC voltage is applied to the telephone line, no voltage is supplied from the power supply unit to the control unit, so that the control unit can be maintained in a stopped state. Therefore, the power consumption of the control unit can be suppressed. When an AC voltage is applied to the telephone line, the voltage of the power supply unit is supplied to the control unit, so that the control unit can be activated.

  The communication apparatus further includes an image forming unit, an operation unit, a main control unit that controls the image forming unit, and a sub control unit that detects an operation of the operation unit. In response to detection of a predetermined operation in the operation unit, the main control unit and the image forming unit are activated and a switch signal is output. The switch unit receives the switch signal, and receives a switch signal between the modem unit and the power supply unit. May be connected.

  According to this configuration, the main control unit and the sub control unit that are operated by the voltage supplied from the power supply unit are provided. When a predetermined signal is input from the modem unit to the sub-control unit in response to the supply of the DC voltage from the DC voltage conversion unit to the modem unit, the sub-control unit outputs a switch signal. When a switch signal is input from the sub control unit to the switch unit, the switch unit connects the modem unit and the power supply unit. Thereby, the voltage of the power supply unit is supplied to the modem unit. As a result, a stable voltage from the power supply unit can be supplied to the modem unit, and the modem unit can be operated stably.

  When the modem unit receives the ring signal, the main control unit and the image forming unit are activated. Therefore, it is not necessary to always activate the main control unit and the image forming unit. Therefore, power consumption by the main control unit and the image forming unit can be suppressed.

  Further, when the user operates the operation unit, the switch unit can be switched between the modem unit and the power supply unit to be connected or disconnected. As a result, regardless of whether or not the modem unit has received the ring signal, the voltage from the power supply unit can be supplied to the modem unit or the supply can be stopped.

  The DC voltage converter has a first input terminal, a second input terminal, a first output terminal, and a second output terminal, the first input terminal is connected to the second electrode, and the second input terminal is connected to the fourth electrode. It may include a diode bridge connected and having the second output terminal grounded.

  According to this configuration, the first input terminal of the diode bridge is connected to the second electrode of the first capacitor. The second input terminal of the diode bridge is connected to the fourth electrode of the second capacitor. Due to the function of the diode bridge, the polarity of the alternating voltage, which is the potential difference between the second electrode and the fourth electrode, can be made uniform.

  The direct-current voltage converter further includes a fifth electrode and a sixth electrode, the fifth electrode is connected to the first output terminal, one end is connected to the sixth electrode, and the other end is connected to the modem unit. A third connection line to be connected, a seventh electrode and an eighth electrode, the seventh electrode being connected to a first connection point located in the middle of the third connection line, and the eighth electrode being grounded And a capacitor.

  According to this configuration, the first output terminal of the diode bridge is connected to the fifth electrode of the resistance element, and the sixth electrode of the resistance element is connected to one end of the third connection line. The first connection point of the third connection line is connected to the seventh electrode of the third capacitor. The eighth electrode of the third capacitor is grounded. Thereby, the resistance element and the third capacitor constitute a low-pass filter that removes a high frequency component of a predetermined frequency or higher from the AC signal component and outputs a low frequency component of a frequency lower than the predetermined frequency from the output end.

  Therefore, the high-frequency component is removed from the full-wave rectified AC voltage output from the first output terminal of the diode bridge by the function of the low-pass filter, and is output to the third connection line.

  The DC voltage conversion unit may further include a Zener diode whose cathode is connected to the second connection point located on the modem unit side of the first connection point in the third connection line, and whose anode is grounded.

  According to this configuration, the second connection point of the third connection line is connected to the cathode of the Zener diode. The anode of the Zener diode is grounded. As a result, the DC voltage input between the anode and cathode of the Zener diode is reduced to one low voltage and output regardless of the magnitude. Therefore, the DC voltage output from the other end of the third connection line can be supplied to the modem unit as a voltage for driving the modem unit.

  The communication device may further include a diode having an anode electrically connected to the DC voltage conversion unit and a cathode electrically connected to the modem unit.

  According to this configuration, the diode is interposed between the DC voltage conversion unit and the modem unit. The anode of the diode is electrically connected to the DC voltage conversion unit, and the cathode of the diode is electrically connected to the modem unit. As a result, it is possible to prevent a current from flowing from the modem unit side to the DC voltage conversion unit.

  According to the present invention, in the communication device, even when the modem unit is in a power-off state, the modem unit can be automatically activated when a ring signal is transmitted from the other party. Therefore, it is not always necessary to monitor whether or not the telephone line is connected to the modem unit. Therefore, it is not necessary to always start the modem unit.

1 is a configuration diagram showing a main configuration of a facsimile apparatus according to an embodiment of the present invention. It is a graph which shows the process in which the ring signal input into the telephone line is converted into a DC voltage. It is a flowchart which shows the flow of operation | movement of modem IC. It is a flowchart which shows the flow of operation | movement of CPU. FIG. 6 is a configuration diagram illustrating a main configuration of an MFP according to a second embodiment. It is a flowchart which shows the flow of operation | movement of the modem IC which concerns on 2nd Embodiment. It is a flowchart which shows the flow of operation | movement of the sub CPU which concerns on 2nd Embodiment. It is a flowchart which shows the flow of operation | movement of main CPU which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Main components of facsimile machine>

  As shown in FIG. 1, the facsimile apparatus 1 as an example of a communication apparatus includes an image reading unit 10, an image forming unit 20, a modular jack 30 as an example of a line connection terminal, a modem unit 40, an operation panel 50, and an ASIC ( Application Specific Integrated Circuit) 60 is provided.

  The image reading unit 10 reads an image formed on a sheet from the sheet, and stores it in a RAM (not shown) as image data.

  The image forming unit 20 performs printing (color printing or monochrome printing) based on image data, and forms an image on a sheet. The image forming method may be an electrophotographic method or an inkjet method.

  The modular jack 30 is a terminal to which one end of a modular cable (not shown) is connected. The modular jack 30 has a first contact 31 and a second contact 32. By inserting the modular cable into the modular jack 30, one of the two office lines of the modular cable is connected to the first contact 31 and the other is connected to the second contact 32. The other end of the modular cable is connected to an exchange (not shown).

  The modem unit 40 includes a DAA (Direct Access Arrangement) 41 and a modem IC 42.

  The DAA 41 is connected to the modular jack 30 by a first connection line 43 connected to the first contact 31 of the modular jack 30 and a second connection line 44 connected to the second contact 32 of the modular jack 30. ing. When the modular cable is inserted into the modular jack 30, the DAA 41 detects the line voltage and detects that the telephone line is connected.

  The modem IC 42 controls communication via a telephone line.

  The operation panel 50 includes a display unit and an operation unit.

  A display part consists of a liquid crystal display, for example. Various information is displayed on the display unit.

  The operation unit includes various operation buttons. Various inputs are possible by pressing the operation buttons. The operation buttons include, for example, a transmission button for confirming various instructions (for example, fax transmission instruction), a cancel button for canceling various instructions, and a cross button for selecting a key displayed on the display unit , Numeric keypad for entering numbers and letters.

  An ASIC 60 as an example of a control unit includes a CPU 61. Facsimile communication data transmitted / received to / from the exchange is input / output to / from the ASIC 60 via the modem unit 40. The CPU 61 controls the image reading unit 10 and the image forming unit 20 by executing programs for various processes based on information input to the ASIC 60, and controls communication via the modem unit 40.

  The facsimile apparatus 1 includes a first capacitor 70, a second capacitor 71, a DC voltage converter 72, a low voltage power supply (LVPS) 73 as an example of a power supply unit, and a switch unit 74.

  The DC voltage conversion unit 72 includes a diode bridge 75, a resistance element 76, a third capacitor 77, a Zener diode 78, and a fourth capacitor 79.

  One electrode (an example of the first electrode) 80 of the first capacitor 70 is connected to the first connection line 43. The other electrode (an example of the second electrode) 81 of the first capacitor 70 is connected to the first input terminal 82 of the diode bridge 75.

  One electrode (an example of a third electrode) 83 of the second capacitor 71 is connected to the second connection line 44. The other electrode (an example of the fourth electrode) 84 of the second capacitor 71 is connected to the second input terminal 85 of the diode bridge 75.

  The first output terminal 86 of the diode bridge 75 is connected to one electrode (an example of a fifth electrode) 87 of the resistance element 76.

  The second output terminal 88 of the diode bridge 75 is grounded.

  The other electrode (an example of a sixth electrode) 89 of the resistance element 76 is connected to one end of the third connection line 90.

  The other end of the third connection line 90 is connected to an anode 92 of a first diode 91 as an example of a diode. The cathode 93 of the first diode 91 is connected to the power supply terminal 94 of the modem IC 42.

  One electrode (an example of a seventh electrode) 95 of the third capacitor 77 is connected to the first connection point 96 of the third connection line 90. The first connection point 96 is located in the middle of the third connection line 90. The other electrode (an example of the eighth electrode) 97 of the third capacitor 77 is grounded.

  Thereby, the resistance element 76 and the third capacitor 77 constitute a low-pass filter that removes a high-frequency component having a predetermined frequency or higher from the AC signal component and outputs a low-frequency component having a frequency lower than the predetermined frequency.

  The cathode 98 of the Zener diode 78 is connected to the second connection point 99 of the third connection line 90. The second connection point 99 is located closer to the first diode 91 than the first connection point 96 in the third connection line 90. The anode 100 of the Zener diode 78 is grounded.

  One electrode 101 of the fourth capacitor 79 is connected to the third connection point 102 of the third connection line 90. The third connection point 102 is located closer to the first diode 91 than the second connection point 99 in the third connection line 90. The other electrode 103 of the fourth capacitor 79 is grounded.

  The DC voltage converter 72 converts the AC signal component into a predetermined DC voltage.

  The plus terminal 105 of the LVPS 73 is connected to the second contact 106 of the switch unit 74. The minus terminal 107 of the LVPS 73 is grounded. The LVPS 73 is a power source for supplying operating power to the modem unit 40 and the ASIC 60. The LVPS 73 is connected to a commercial power source.

  The first contact 108 of the switch unit 74 is connected to the power supply terminal 109 of the ASIC 60 and the anode 111 of the second diode 110.

  The cathode 112 of the second diode 110 is connected to the power supply terminal 94 of the modem IC 42.

  Further, a signal line 113 from the modem IC 42 and a signal line 114 from the operation panel 50 are connected to the switch unit 74. The switch unit 74 is, for example, a semiconductor switch. When a switch signal is input via the signal line 113 from the modem IC 42 or the signal line 114 from the operation panel 50, the switch unit 74 is connected between the first contact 108 and the second contact 106. Closed. The switch unit 74 disconnects the first contact 108 and the second contact 106 when no switch signal is input via the signal line 113 from the modem IC 42 or the signal line 114 from the operation panel 50. Will be open. In the following, a switch signal being input or output is referred to as a switch-on signal being input or output, and a switch signal is not being input or output, a switch-off signal being input or output. That's it.

<Generation of modem IC startup voltage>

  The starting voltage of the modem IC 42 is generated by converting the ring signal flowing through the telephone line into a DC voltage by the first capacitor 70, the second capacitor 71, and the DC voltage converter 72.

  The ring signal flowing through the telephone line is a signal in which a DC voltage (bias) of about 48 V is superimposed on an AC voltage signal, as shown in FIG.

  Due to the functions of the first capacitor 70 and the second capacitor 71, as shown in FIG. 2B, the DC voltage is cut from the ring signal, and the electrode 81 of the first capacitor 70, the electrode 84 of the second capacitor 71, During this period, an AC voltage that is a potential difference between the electrode 81 of the first capacitor 70 and the electrode 84 of the second capacitor 71 is generated.

  Due to the function of the diode bridge 75, as shown in FIG. 2C, the polarity of the AC voltage, which is the potential difference between the electrode 81 of the first capacitor 70 and the electrode 84 of the second capacitor 71, is a single polarity. Are input to the resistance element 76.

  The alternating voltage input to the resistance element 76 is a low-frequency filter from which a high-frequency component has been removed as shown in FIG. 2D by the function of a low-pass filter constituted by the resistance element 76 and the third capacitor 77. Converted to AC voltage.

  This low-frequency AC voltage is converted to a constant voltage of 3.3 V by the function of the Zener diode 78 and input to the modem IC 42 as shown in FIG.

<Operation of modem IC>

  When a ring signal flows through the telephone line with the modular cable connected to the exchange connected to the modular jack 30, the first capacitor 70, the second capacitor 71, and the DC voltage conversion unit 72 cause the ring signal to become 3. It is converted to a DC voltage of 3V and input to the modem IC 42. As a result, the modem IC 42 is activated, and the process shown in FIG. 3 is executed in the modem IC 42.

  After activation, the modem IC 42 first outputs a switch-on signal to the signal line 113 (S1). As a result, the switch unit 74 is closed, and the power from the LVPS 73 is supplied to the ASIC 60 and the modem IC 42. Then, the CPU 61 is activated. Thereafter, the power from the LVPS 73 is used as the driving power for the modem unit 40.

  Then, the modem IC 42 executes communication processing started by the ring signal in cooperation with the CPU 61 (S2).

  Then, the modem IC 42 stands by until a communication end signal is received from the CPU 61 (S3: NO).

  When the communication end signal is received (S3: YES), the modem IC 42 outputs a switch-off signal to the switch unit 74 (S4). Thereby, the switch part 74 will be in an open state, and the electric power supply from LVPS73 to ASIC60 and modem IC42 will be stopped. Then, the CPU 61 and the modem IC 42 are stopped.

<CPU operation>

  When the CPU 61 is activated by switching the switch unit 74 from the open state to the closed state, the CPU 61 executes the process shown in FIG.

  When the CPU 61 is activated, the modem unit 40 receives a ring signal via a telephone line. Therefore, the CPU 61 executes communication control for the modem IC 42 (S11).

  When the communication is completed, the CPU 61 outputs a communication end signal to the modem IC 42 (S12).

<Operating power of modem IC>

  According to the ringing signal (ring signal) transmission conditions defined in Schedule 4 of the Telecommunication Equipment Rules for Business, the ring signal transmission voltage is (75-10) V (rms) or higher, (75 + 8) V ( rms) or less, and the fluctuation value is determined to be 100 V or less (wave height value ÷ value in √2).

  If the ring signal is a sinusoidal alternating current, the minimum value of the peak value (peak-to-peak value in the sine waveform) is 183.85 (V) according to the following equation (1).

  Vmin = (75-10) × 2 × √2 = 183.85 (V) (1)

  Since the fluctuation value is 100 (V) or less, the ring signal applied to the terminal device when the fluctuation value is taken into account is 83.85 (V) or more.

  Also, Article 13, Paragraph 2, Item 3 of the Regulations for Terminal Equipment, etc. defines that the impedance of the DC circuit when receiving a paging signal is 2 kΩ or more as an electrical condition of the DC circuit.

  Therefore, when the power for starting a circuit having a resistance value of 2 kΩ with the ring signal is calculated using the expected value of the ring signal when the fluctuation value is taken into account, the following expression (2) gives 3685.11 (mW )

P = V ² ÷ R = (83.85) ² ÷ 2k = 3685.11 (mW) (2)

  Many modem ICs can be driven with a power of 3685.11 (mW) or less. Therefore, it is possible to start the modem IC using the DC voltage converted from the ring signal.

<Effect>

  As described above, in the state where the telephone line is connected to the modular jack 30 of the facsimile apparatus 1, a DC voltage of about 48V is constantly applied. In the ring signal sent from the other party to the facsimile apparatus 1 through the telephone line, an AC voltage is superimposed on the DC voltage. The first capacitor 70 and the second capacitor 71 do not pass the DC voltage component that is always applied, but only pass the AC voltage component of the ring signal transmitted from the counterpart side. Then, the potential difference of the passed AC voltage component is converted into a DC voltage, and the DC voltage is supplied to the modem unit 40.

  Then, in the facsimile apparatus 1, even when the modem unit 40 is in a power-off state, the modem unit 40 is automatically activated when a ring signal is transmitted from the other party. Therefore, it is not necessary to always start the modem unit 40.

  The facsimile machine 1 further includes an LVPS 73 and a switch unit 74. The LVPS 73 is connected to a commercial power source and outputs a DC voltage. The switch unit 74 is provided between the modem unit 40 and the LVPS 73, and connects or disconnects the modem unit 40 and the LVPS 73. The modem unit 40 outputs a switch-on signal in response to the supply of the DC voltage from the DC voltage conversion unit 72. The switch unit 74 connects the modem unit 40 and the LVPS 73 in accordance with a switch-on signal.

  The LVPS 73 and the modem unit 40 are connected, and the voltage of the LVPS 73 is supplied to the modem unit 40. As a result, a stable voltage from the LVPS 73 can be supplied to the modem unit 40, and the modem unit 40 can be operated stably.

  The facsimile machine 1 further includes an ASIC 60. The ASIC 60 is connected to the LVPS 73 via the switch unit 74. The modem unit 40 outputs a switch-on signal in response to the supply of the DC voltage from the DC voltage conversion unit 72. The switch unit 74 sets the connection state between the ASIC 60 and the LVPS 73 in accordance with the switch-on signal.

  Since no voltage is supplied from the LVPS 73 to the ASIC 60 before the AC voltage is applied to the telephone line, the ASIC 60 can be maintained in a stopped state. Therefore, the power consumption of the ASIC 60 can be suppressed. When an AC voltage is applied to the telephone line, the voltage of the LVPS 73 is supplied to the ASIC 60, so that the ASIC 60 can be activated.

  The DC voltage conversion unit 72 includes a diode bridge 75. The diode bridge 75 has a first input terminal 82, a second input terminal 85, a first output terminal 86, and a second output terminal 88. The diode bridge 75 has a first input terminal 82 of the first capacitor 70. Connected to the electrode 81, the second input terminal 85 is connected to the electrode 84 of the second capacitor 71, and the second output terminal 88 is grounded.

  With the function of the diode bridge 75, the polarity of the AC voltage, which is the potential difference between the electrode 81 of the first capacitor 70 and the electrode 84 of the second capacitor 71, can be made uniform.

  The DC voltage conversion unit 72 further includes a resistance element 76, a third connection line 90, and a third capacitor 77. The resistance element 76 includes an electrode 87 and an electrode 89. The resistor element 76 has an electrode 87 connected to the first output terminal 86 of the diode bridge 75. One end of the third connection line 90 is connected to the electrode 89 of the resistance element 76, and the other end is connected to the modem unit 40 via the first diode 91. The third capacitor 77 has an electrode 95 and an electrode 97. In the third capacitor 77, the electrode 95 is connected to a first connection point 96 located in the middle of the third connection line 90, and the electrode 97 is grounded.

  Thereby, the resistance element 76 and the third capacitor 77 constitute a low-pass filter that removes a high frequency component of a predetermined frequency or higher from the AC signal component and outputs a low frequency component of a frequency lower than the predetermined frequency from the output end.

  Therefore, the high-frequency component is removed from the full-wave rectified AC voltage output from the first output terminal 86 of the diode bridge 75 by the function of the low-pass filter and output to the third connection line 90.

  The DC voltage converter 72 further includes a Zener diode 78. In the Zener diode 78, the cathode 98 is connected to the second connection point 99 located on the modem unit 40 side of the first connection point 96 in the third connection line 90, and the anode 100 is grounded.

  As a result, the DC voltage input between the anode 100 and the cathode 98 of the Zener diode 78 is reduced to one low voltage and output regardless of the magnitude. Therefore, the DC voltage output from the other end of the third connection line 90 (the end connected to the anode 92 of the first diode 91) is supplied to the modem unit 40 as a voltage for driving the modem unit 40. Can do.

  The facsimile apparatus 1 further includes a first diode 91 whose anode 92 is electrically connected to the DC voltage conversion unit 72 and whose cathode 93 is electrically connected to the modem unit 40.

  As a result, it is possible to prevent a current from flowing from the modem unit 40 side to the DC voltage conversion unit 72.

Second Embodiment

  As an example of the communication apparatus, an MFP (Multi-Function Peripheral) may be employed instead of the facsimile apparatus 1. In that case, the MFP may have the configuration shown in FIG. 5 instead of the configuration shown in FIG.

  As shown in FIG. 5, the MFP 201 includes an image reading unit 210, an image forming unit 220, a network interface (I / F) 230, a modular jack 240 as an example of a line connection terminal, a modem unit 250, an operation panel 260, and an ASIC 270. It has.

  The image reading unit 210 reads an image formed on the sheet from the sheet, and stores it as image data in a RAM (not shown).

  The image forming unit 220 performs printing (color printing or monochrome printing) based on image data, and forms an image on a sheet. The image forming method may be an electrophotographic method or an inkjet method.

  The network interface 230 is an interface for communication with an external device such as a PC connected to the LAN. The communication method may be a wireless communication method or a wired communication method.

  The modular jack 240 is a terminal to which a modular cable connected to an unshown exchange is connected. The modular jack 240 has a first contact 241 and a second contact 242. By inserting the modular cable into the modular jack 240, one of the two office lines of the modular cable is connected to the first contact 241 and the other is connected to the second contact 242.

  The modem unit 250 includes a DAA 251 and a modem IC 252 as an example of a modem circuit.

  The DAA 251 is connected to the modular jack 240 by a first connection line 253 connected to the first contact 241 of the modular jack 240 and a second connection line 254 connected to the second contact 242 of the modular jack 240. ing. When the modular cable is inserted into the modular jack 240, the DAA 251 detects the line voltage and detects that the telephone line is connected.

  The modem IC 252 controls communication via a telephone line.

  The operation panel 260 includes a display unit and an operation unit.

  A display part consists of a liquid crystal display, for example. Various information is displayed on the display unit.

  The operation unit includes various operation buttons. Various inputs are possible by pressing the operation buttons. The operation buttons include, for example, a transmission button for confirming various instructions (for example, fax transmission instruction), a cancel button for canceling various instructions, and a cross button for selecting a key displayed on the display unit , Numeric keypad for entering numbers and letters.

  The ASIC 270 includes a main CPU 271 as an example of a main control unit and a sub CPU 272 as an example of a sub control unit. Facsimile communication data transmitted / received to / from the exchange is input / output to / from the ASIC 270 via the modem unit 250. The main CPU 271 controls the image reading unit 210 and the image forming unit 220 by executing programs for various processes based on information input to the ASIC 270 and controls communication via the network interface 230. . The sub CPU 272 controls the image reading unit 210 and the image forming unit 220 by executing programs for various processes based on information input to the ASIC 270 and controls communication via the modem unit 250. . The main CPU 271 is activated by an activation signal from the sub CPU 272.

  The MFP 201 includes a first capacitor 281, a second capacitor 282, a DC voltage conversion unit 72, a low voltage power supply LVPS (Low Voltage Power Supply) 283 as an example of a power supply unit, and a switch unit 284.

  The DC voltage converter 72 has the same configuration as the DC voltage converter 72 shown in FIG. Therefore, in FIG. 5, parts corresponding to the respective parts of the DC voltage converter 72 shown in FIG. 1 are denoted by the same reference numerals as those parts. Description of the DC voltage converter 72 shown in FIG. 5 is omitted.

  One electrode (an example of the first electrode) 291 of the first capacitor 281 is connected to the first connection line 253. The other electrode (an example of the second electrode) 292 of the first capacitor 281 is connected to the first input terminal 82 of the diode bridge 75.

  One electrode (an example of a third electrode) 293 of the second capacitor 282 is connected to the second connection line 254. The other electrode (an example of a fourth electrode) 294 of the second capacitor 282 is connected to the second input terminal 85 of the diode bridge 75.

  The other end of the third connection line 90 is connected to the anode 296 of the diode 295. The cathode 297 of the diode 295 is connected to the power supply terminal 298 of the modem IC 252.

  A plus terminal 299 of the LVPS 283 is connected to the second contact 300 of the switch unit 284 and the ASIC 270. The minus terminal 301 of the LVPS 283 is grounded. The LVPS 283 is a power source for supplying operating power to the modem unit 250 and the ASIC 270. The LVPS 283 is connected to a commercial power source.

  The first contact 302 of the switch unit 284 is connected to the power supply terminal 298 of the modem IC 252 and the cathode 297 of the diode 295.

  Further, the signal line 303 from the sub CPU 272 is connected to the switch unit 284. The switch unit 284 is, for example, a semiconductor switch. The switch unit 284 is in a closed state in which the first contact 302 and the second contact 300 are connected when a switch-on signal is input via the signal line 303 from the sub CPU 272. The switch unit 284 is in an open state in which the first contact 302 and the second contact 300 are disconnected when a switch-off signal is input via the signal line 303 from the sub CPU 272.

  The modem IC 252 outputs an activation notification signal to the sub CPU 272 when the modem IC 252 is activated.

  The sub CPU 272 detects an input to the operation panel 260 when an instruction to execute a function of the MFP 201 such as an instruction to cancel the energy saving mode, a fax transmission instruction, a copy instruction, or an image reading instruction is input.

  The sub CPU 272 outputs a switch-on signal to the switch unit 284 when the activation notification signal is input from the modem IC 252. Further, when the sub CPU 272 receives an instruction to execute a function of the MFP 201 such as an instruction to cancel the energy saving mode, a fax transmission instruction, a copy instruction, or an image reading instruction on the operation panel 260 and detects the input, A switch-on signal is output to the switch unit 284.

<Operation of modem IC>

  When a ring signal flows through the telephone line in a state where the modular cable connected to the exchange is connected to the modular jack 30, the first capacitor 281, the second capacitor 282 and the DC voltage conversion unit 72 cause the ring signal to be 3. It is converted to a DC voltage of 3V and input to the modem IC 252. As a result, the modem IC 252 is activated, and the process shown in FIG. 6 is executed in the modem IC 252.

  After the activation, the modem IC 252 first outputs an activation notification signal to the sub CPU 272 (S21).

  Then, the modem IC 252 executes communication processing started by the ring signal in cooperation with the main CPU 271 (S22).

<Operation of sub CPU>

  While the MFP 201 is powered on, the sub CPU 272 of the ASIC 270 repeatedly executes the process shown in FIG.

  The sub CPU 272 determines whether an activation notification signal is input from the modem IC 252 (S31).

  When the activation notification signal is input (S31: YES), the sub CPU 272 outputs a switch-on signal to the signal line 303. As a result, the switch unit 284 is closed, and power from the LVPS 283 is supplied to the modem IC 252. Then, the driving power of the modem IC 252 is switched to the power from the LVPS 283.

  When the activation notification signal is not input (S31: NO), the sub CPU 272 determines whether or not a fax-on that is an instruction to activate the fax function of the MFP 201 is accepted as an input from the operation panel 260 (S32). ).

  When the fax-on is not accepted (S32: NO), the sub CPU 272 repeats the processes after step S31 described above.

  When fax-on is accepted (S32: YES), the sub CPU 272 outputs a switch-on signal to the signal line 303 (S33). As a result, the switch unit 284 is closed, and power from the LVPS 283 is supplied to the modem IC 252. Then, the driving power of the modem IC 252 is switched to the power from the LVPS 283.

  After outputting the switch-on signal to the signal line 303, the sub CPU 272 activates the main CPU 271 (S34).

  Then, the sub CPU 272 stands by until a communication end signal is received from the main CPU 271 (S35: NO).

  When the communication end signal is received (S35: YES), the sub CPU 272 stops the main CPU 271 (S36).

  Then, the sub CPU 272 outputs a switch-off signal to the signal line 303 (S37). As a result, the switch unit 284 is opened, and the supply of voltage from the LVPS 283 to the modem IC 252 is stopped. Then, the modem IC 252 is stopped.

<Operation of main CPU>

  When activated by the sub CPU 272, the main CPU 271 executes the processing shown in FIG.

  When the main CPU 271 is activated, the modem unit 250 receives a ring signal via a telephone line. Therefore, the main CPU 271 executes communication control for the modem IC 252 (S41).

  When the communication is completed, the main CPU 271 outputs a communication end signal to the sub CPU 272 (S42).

<Effect>

  The MFP 201 includes an image forming unit 220, an operation panel 260, a main CPU 271 that controls the image forming unit 220, and a sub CPU 272 that detects an operation from the operation panel 260.

  The sub CPU 272 executes a function provided in the MFP 201 such as input of a startup notification signal from the modem unit 250 or a predetermined operation on the operation panel 260, for example, an instruction to cancel the energy saving mode, a fax transmission instruction, a copy instruction, or an image reading instruction. Upon receiving the instruction input operation, the main CPU 271 and the image forming unit 200 are activated, and a switch-on signal is output to the signal line 303.

  The switch unit 284 receives the switch-on signal and connects between the modem unit 250 and the LVPS 283.

  As a result, the voltage of the LVPS 283 is supplied to the modem unit 250. As a result, a stable voltage from the LVPS 283 can be supplied to the modem unit 250, and the modem unit 250 can be stably operated.

  When the modem unit 250 receives a ring signal, the main CPU 271 and the image forming unit 220 are activated. Therefore, power consumption by the main CPU 271 and the image forming unit 220 can be suppressed.

  Further, when the user operates the operation panel 260, the switch unit 284 can switch between the modem unit 250 and the LVPS 283 between connection and disconnection. Thereby, the voltage from the LVPS 283 can be supplied to the modem unit 250 or can be stopped regardless of whether or not the modem unit 250 has received the ring signal.

<Modification>

  As mentioned above, although embodiment of this invention was described, this invention can also be implemented with another form.

  For example, in the above-described embodiment, when communication by the modem unit 250 is not performed, the main CPU 271 is stopped and the sub CPU 272 is activated. At this time, the operation clock of the sub CPU 272 may be made slower than the operation clock when communication by the modem unit 250 is performed. Thereby, the power consumption by the sub CPU 272 when the modem unit 250 is not communicating can be further reduced.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

DESCRIPTION OF SYMBOLS 1 Facsimile apparatus 30 Modular jack 31 1st terminal 32 2nd terminal 40 Modem part 43 1st connection line 44 2nd connection line 60 ASIC
70 First Capacitor 71 Second Capacitor 72 DC Voltage Converter 73 LVPS
74 Switch unit 75 Diode bridge 76 Resistor element 77 Third capacitor 78 Zener diode 80 Electrode 81 Electrode 83 Electrode 84 Electrode 82 First input terminal 85 Second input terminal 86 First output terminal 87 Second output terminal 87 Electrode 89 Electrode 90 First 3 connection lines 91 first diode 92 anode 93 cathode 95 electrode 96 first connection point 97 electrode 98 cathode 99 second connection point 100 anode 201 MFP
220 Image Forming Unit 260 Operation Panel 271 Main Control Unit 272 Sub Control Unit 283 LVPS
284 Switch part

Claims (8)

A line connection terminal having two terminals connectable to a telephone line;
A modem unit connected to one terminal of the line connection terminal via a first connection line, and connected to the other terminal of the line connection terminal via a second connection line;
A first capacitor having a first electrode and a second electrode, wherein the first electrode is connected to the first connection line;
A second capacitor having a third electrode and a fourth electrode, wherein the third electrode is connected to the second connection line;
Among the voltages applied to the telephone line, the AC voltage that passes through the first capacitor and is output from the second electrode, and the voltage that is applied to the telephone line passes through the second capacitor and is output from the fourth electrode. A DC voltage conversion unit that converts a potential difference between the AC voltage and the DC voltage to a DC voltage;
With
The modem unit is activated by the DC voltage converted by the DC voltage conversion unit.
Communication device. The communication device according to claim 1,
In addition,
A power source connected to a commercial power source and outputting a DC voltage;
A switch unit that is provided between the modem unit and the power supply unit, and that connects or disconnects the modem unit and the power supply unit;
With
The modem unit outputs a predetermined signal in response to the supply of the DC voltage from the DC voltage conversion unit,
The switch unit connects the modem unit and the power supply unit by the predetermined signal.
Communication device. The communication device according to claim 2,
In addition,
Control unit,
With
The control unit is connected to the power supply unit via the switch unit,
The modem unit outputs the predetermined signal in response to the supply of a DC voltage from the DC voltage conversion unit,
The switch unit receives the input of the predetermined signal and connects between the control unit and the power supply unit.
Communication device. The communication device according to claim 2,
In addition,
An image forming unit;
An operation unit;
A main control unit for controlling the image forming unit;
A sub-control unit that detects an operation of the operation unit;
With
The sub-control unit receives the input of the predetermined signal or detection of a predetermined operation in the operation unit, activates the main control unit and the image forming unit, and outputs a switch signal,
The switch unit receives the switch signal and connects between the modem unit and the power supply unit.
Communication device. The communication device according to any one of claims 1 to 4,
The DC voltage converter is
A first input terminal; a second input terminal; a first output terminal; and a second output terminal, wherein the first input terminal is connected to the second electrode, and the second input terminal is connected to the fourth electrode. A diode bridge having the second output terminal grounded;
Communication device. The communication device according to claim 5,
The direct current voltage converter further includes:
A resistance element having a fifth electrode and a sixth electrode, wherein the fifth electrode is connected to the first output terminal;
A third connection line having one end connected to the sixth electrode and the other end connected to the modem unit;
A third capacitor having a seventh electrode and an eighth electrode, wherein the seventh electrode is connected to a first connection point located in the middle of the third connection line, and the eighth electrode is grounded.
Communication device. The communication device according to claim 6,
The direct current voltage converter further includes:
A cathode is connected to a second connection point located closer to the modem unit than the first connection point in the third connection line, and includes a Zener diode whose anode is grounded.
Communication device. The communication device according to any one of claims 1 to 7,
In addition,
A diode whose anode is electrically connected to the DC voltage converter and whose cathode is electrically connected to the modem;
Comprising
Communication device.

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