JP6361429B2 - Facsimile machine - Google Patents

Description

  The present invention relates to a facsimile apparatus that can be connected to an external telephone, can detect an off-hook state of the external telephone, and can return from the power saving state based on the detection.

  2. Description of the Related Art In recent years, it is known that a facsimile machine uses a data access device (Data Access Arrangement, hereinafter referred to as “semiconductor DAA”) as an interface unit with a telephone line network. In addition, a method of using an external telephone connected to the facsimile apparatus and using the same telephone line for the facsimile apparatus and the external telephone is known.

  By the way, when a closed circuit is configured between the telephone line network, the facsimile apparatus, and the external telephone in conjunction with the off-hook of the external telephone receiver, the detected line voltage decreases, and the external telephone receiver becomes A facsimile apparatus that determines that an off-hook has occurred is known. In particular, Patent Document 1 includes a detection circuit that is connected to a telephone line network to a semiconducting DAA and detects a voltage fluctuation of the telephone line. A facsimile machine to be restored is disclosed.

JP 2014-36379 A

  Now, the line voltage has a fixed value depending on the country. For example, in Japan, the line voltage is 48V. However, the line voltage may be connected to a load such as a distributor or TA (Terminal Adapter) between the telephone line network and the facsimile apparatus. In this case, the line voltage supplied to the facsimile apparatus is reduced due to the resistance component of the load.

  Then, when the line voltage supplied to the facsimile apparatus is reduced, the line voltage fluctuation itself due to the off-hook of the handset of the external telephone is also reduced in proportion to the reduction of the line voltage. There is a problem that the facsimile apparatus cannot determine that the handset of the external telephone is off-hook, and cannot return from the power saving mode.

  The present invention has been proposed in view of the above-described problems, and even when the line voltage supplied to the facsimile apparatus is small, the off-hook of the external telephone is reliably detected and returned from the power saving mode. An object is to provide a facsimile machine.

  The facsimile apparatus according to the present invention includes a pair of line connection terminals, a data access unit, a pair of external telephone connection terminals, a modem unit, a current detection element, and a switch element. The pair of line connection terminals can be connected to a telephone line network. The data access unit has a voltage detection circuit. The voltage detection circuit is connected to each terminal of the pair of line connection terminals via the pair of first connection lines, and detects a fluctuation of the voltage between the pair of first connection lines that exceeds a specified value. The data access unit transmits and receives signals to and from the telephone line network via a pair of line connection terminals. The pair of external telephone connection terminals are a pair of terminals that can connect the external telephone to the telephone network. Each terminal is connected to a pair of first connection lines via a pair of second connection lines. The modem unit is connected to the data access unit, and modulates and demodulates signals transmitted and received via the data access unit. The current detection element detects a current flowing through the pair of second connection lines in response to the off-hook operation of the external telephone connected to the pair of external telephone connection terminals. The switch element is provided between the pair of first connection lines, and conducts between the pair of first connection lines in response to detection of current by the current detection element. The modem unit can transition between a normal mode in which power is supplied to the modem unit and a power saving mode in which power supply to the modem unit is suppressed compared to the normal mode. The voltage detection circuit detects a fluctuation exceeding a specified value by the conduction of the switch element. The data access unit transmits a transition signal instructing a transition from the power saving state to the normal state to the modem unit by detecting the fluctuation of the voltage detection circuit.

  Accordingly, the current element detects a current flowing through the pair of second connection lines in response to the off-hook of the external telephone connected to the pair of external telephone connection terminals. When the switch element is brought into conduction between the pair of first connection lines by the flowing current, the voltage between the first connection lines becomes zero, and thus the voltage detection circuit inevitably detects a fluctuation exceeding the specified value. It will be. Since the data access unit can transmit a signal instructing the modem unit to transition from the power saving mode to the normal mode, the facsimile apparatus can return from the power saving mode.

  The facsimile apparatus according to the present invention further includes a capacitor connected in series with the switch element between the pair of first connection lines.

  Thereby, since the capacitor is connected in series with the switch element, the terminals of the capacitor are connected to the pair of first connection lines according to the conduction of the switch element, and charging of the capacitor is started. As a result, the voltage between the pair of first connection lines changes from the original voltage before the switch element becomes conductive to a lower voltage, and then returns to the original voltage again after the capacitor is charged. Presents fluctuations. The voltage detection circuit can detect a transient voltage fluctuation from the original voltage to a low voltage. In addition, after the capacitor is charged, no current flows between the pair of first connection lines even if the switch element is in a conductive state. Even after detecting the required voltage fluctuation, current does not continue to flow and current consumption does not increase.

  In the facsimile apparatus according to the present invention, the current detection element is a light emitting element that emits light in response to a current flowing. The switch element is a phototransistor that is turned on by light emission of the light emitting element. The light emitting element and the phototransistor constitute a photocoupler.

  Accordingly, the current flowing through the pair of second connection lines can be detected by the light emitting element and the phototransistor provided in the photocoupler, and the voltage between the pair of first connection lines can be varied. By adding an electronic component called a photocoupler, it is possible to realize a configuration that reliably detects off-hook of an external telephone.

  In the facsimile apparatus according to the present invention, the light emitting element includes a first light emitting diode and a second light emitting diode. The first light emitting diode is provided in a current path flowing through the pair of second connection lines. The second light emitting diode is connected in parallel to the first light emitting diode, the anode is connected to the cathode side of the first light emitting diode, and the cathode is connected to the anode side of the first light emitting diode.

  Thus, the line connection terminal can be connected in either the positive or negative direction with respect to the positive / negative voltage of the line voltage of the telephone line network. Thereby, the positive / negative polarity of the voltage applied to a pair of 1st connection line may reverse, and the direction of the electric current which flows into a pair of 2nd connection line may reverse in connection with this. By providing the first light-emitting diode and the second light-emitting diode in a state of being connected in parallel, the current flowing through the pair of second connection lines can be detected regardless of the connection direction to the telephone line network.

  In the facsimile apparatus according to the present invention, the modem unit transmits a first operation clock signal to the data access unit when in the normal mode, and to the data access unit when in the power saving mode. A second operation clock signal having a frequency lower than that of the first operation clock signal is transmitted. The data access unit detects the voltage value between the pair of first connection lines by the voltage detection circuit while the first operation clock signal is transmitted from the modem unit, and at a predetermined interval based on the first operation clock signal. The voltage value is periodically transmitted to the modem unit. Further, while the second operation clock signal is transmitted from the modem unit, the voltage detection circuit detects whether or not the voltage fluctuation between the pair of first connection lines exceeds a specified value.

  Thus, in the normal mode, it is necessary not only to see the off-hook state of the external telephone, but also to see whether the line is connected or disconnected. For this reason, in the normal operation mode, the voltage value is periodically transmitted to the modem unit at a predetermined interval based on the first operation clock signal to check whether the line is connected or disconnected. Yes. On the other hand, in the power saving mode, it is not necessary to regularly check the voltage value regularly from the viewpoint of power saving. Accordingly, whether or not the voltage access circuit drives the data access unit with the second operation clock signal having a frequency lower than the frequency of the first operation clock signal and the voltage detection circuit exceeds a specified value between the pair of first connection lines. By detecting this, power saving can be achieved.

  The facsimile apparatus according to the present invention further includes a control unit and a display unit. When the control unit receives a transition signal from the data access unit by the modem unit and receives a return notification from the power saving mode transmitted from the modem unit, the external telephone is being used for the display unit. To indicate that it is.

  Thus, when the external telephone enters an off-hook state, the telephone line is occupied by the external telephone. Therefore, the fact that the external telephone is in use is displayed on the display unit of the facsimile apparatus. It is possible to notify the user who is using that the telephone line is occupied.

  According to the communication apparatus according to the present application, even when the line voltage supplied to the facsimile apparatus is small, the off-hook of the external telephone can be reliably detected.

1 is a diagram illustrating a circuit configuration of a facsimile apparatus according to an embodiment. It is a figure which shows the transition characteristic of the line voltage at the time of the conventional off-hook. It is a figure which shows the transition characteristic of the line voltage at the time of off-hook of embodiment. It is a flowchart which shows the transition between the normal mode and power saving mode in ASIC of embodiment. It is a flowchart which shows the power saving mode process of embodiment. It is a flowchart which shows the transition between the normal mode and power saving mode in the modem part of embodiment.

  FIG. 1 is a diagram showing a circuit configuration of a facsimile apparatus (hereinafter referred to as a FAX apparatus) 1 according to an embodiment of the present application. FIG. 1 shows the FAX apparatus 1 in a state where a telephone line network 60 and an external telephone 70 are connected.

  The FAX apparatus 1 includes a line connection terminal 11, a telephone connection terminal 12, a photocoupler 14, a capacitor 15, a diode bridge 16, a switch 17, a semiconductor DAA 20, a transformer 18, a modem unit 30, an ASIC 40, a ROM 43, a RAM 44, an operation unit 45, An image forming unit 46, an image reading unit 47, and a display unit 48 are provided.

  The line connection terminal 11 and the telephone connection terminal 12 are terminals provided so that lines and devices can be connected to the outside of the FAX apparatus 1, and are, for example, modular jacks. The line connection terminal 11 is connected to an exchange (not shown) via the telephone line network 60. The telephone connection terminal 12 is a terminal to which an external telephone 70 can be connected. The line connection terminal 11 has terminals 11A and 11B. The telephone connection terminal 12 has terminals 12A and 12B.

  The semiconductor DAA 20 includes a voltage monitoring unit 21, a line signal receiving circuit 22, a line signal sending circuit 23, a data input / output unit 24, a well-known ring detection circuit (not shown), and the like. The voltage monitoring unit 21 is connected to the telephone line network 60 via the line connection terminal 11. The terminal 11A and the voltage monitoring unit 21 are connected by a transmission path 13A. The terminal 11B and the voltage monitoring unit 21 are connected by a transmission path 13B. The voltage monitoring unit 21 detects a line voltage VS that is a voltage between the transmission paths 13A and 13B. The line signal receiving circuit 22 closes the telephone line network 60 when receiving a FAX. The line signal transmission circuit 23 closes the telephone line network 60 at the time of FAX transmission. The data input / output unit 24 performs A / D conversion and D / A conversion of FAX reception data and FAX transmission data. Further, at the time of FAX reception, a signal such as a ring detection signal transmitted from the ring detection circuit and FAX reception data output from the line signal reception circuit 22 are converted into serial data. Further, at the time of FAX transmission, a control signal for controlling the semiconductor DAA 20 output from the ASIC 40 and FAX transmission data are separated.

  The photocoupler 14 includes a phototransistor 14a and light emitting diodes 14b and 14c. The phototransistor 14a is connected between the transmission path 13A and the first terminal of the capacitor 15. The second terminal of the capacitor 15 is connected to the transmission path 13B. The node N1 on the transmission path 13A and the terminal 12A are connected by the transmission path 13C. The node N2 on the transmission path 13B and the terminal 12B are connected by the transmission path 13D. The light emitting diodes 14b and 14c are connected on the transmission path 13D. The anode of the light emitting diode 14b is connected to the terminal 12B side, and the cathode is connected to the node N2 side. The anode of the light emitting diode 14c is connected to the node N2 side, and the cathode is connected to the terminal 12B side. The diode bridge 16 is connected between the transmission paths 13A and 13B. As a result, the DC loop current that flows when the telephone network 60 is closed is rectified. The current rectified by the diode bridge 16 is input to the line signal receiving circuit 22 via the transmission path 13E. The transmission path 13E is connected to the line signal transmission circuit 23 via the switch 17. The switch 17 is controlled by the data input / output unit 24, and is turned off at the time of FAX reception and turned on at the time of FAX transmission.

  The modem unit 30 is connected to the semiconductor DAA 20 via the transformer 18. A clock unit 31 is also provided. The modem unit 30 performs modulation / demodulation of FAX reception data and FAX transmission data. The clock unit 31 modulates the clock signal CK1 or CK2 transmitted from the ASIC 40 to generate the clock signal CLK2 or CLK3. The clock signals CLK 2 and CLK 3 are transmitted to the data input / output unit 24 of the semiconductor DAA 20 via a transformer (not shown) different from the transformer 18.

  The ASIC 40 has a function of controlling the entire FAX apparatus 1. In addition, a CPU 41 and a clock generation unit 42 are provided. Further, the ROM 43, the RAM 44, the operation unit 45, the image forming unit 46, the image reading unit 47, and the display unit 48 are connected via the bus 49. The CPU 41 controls the operation unit 45, the image forming unit 46, the image reading unit 47, the display unit 48, and the like by executing various programs stored in the ROM 43. The ROM 43 stores a control program and various data. The RAM 44 is used as a main storage device for the CPU 41 to execute various processes.

  The operation unit 45 includes various keys and an operation panel. The various keys are, for example, a start key and a numeric keypad. The user can perform various operations using various keys and an operation panel. The image forming unit 46 is, for example, an ink jet printer. The image reading unit 47 reads the document inserted into the document insertion slot as image data. The display unit 48 includes a liquid crystal display, for example, and can display the operation state of the FAX apparatus 1.

  When the external telephone 70 is in an on-hook state, a switch (not shown) built in the external telephone 70 is off, and the external telephone 70 is electrically disconnected from the FAX apparatus 1. In FAX reception, when the FAX apparatus 1 receives FAX reception data, the FAX reception data is transmitted to the modem unit 30 via the semiconductor DAA 20 and the transformer 18. The FAX reception data is demodulated by the modem unit 30, transferred to the ASIC 40, and stored in the RAM 44. The FAX reception data stored in the RAM 44 by the image forming unit 46 is image-formed.

  Incidentally, the FAX apparatus 1 has a normal mode and a power saving mode. In the normal mode, the ASIC 40, the modem unit 30, and the semiconductor DAA 20 operate based on a predetermined clock signal. On the other hand, in the power saving mode, the modem unit 30, the data input / output unit 24, and the voltage monitoring unit 21 operate based on a clock signal having a frequency lower than that in the normal mode. Further, the image forming unit 46, the image reading unit 47, the line signal receiving circuit 22, and the line signal sending circuit 23 are stopped.

  explain in detail. In the normal mode, the clock signal CK 1 is transmitted from the clock generation unit 42 to the clock unit 31. Then, the clock signal 31 is generated in the clock unit 31 and transmitted to the data input / output unit 24. Furthermore, the clock signal CLK 2 is transmitted from the data input / output unit 24 to the voltage monitoring unit 21, the line signal receiving circuit 22, and the line signal sending circuit 23. On the other hand, in the power saving mode, the clock signal CK <b> 2 is transmitted from the clock generation unit 42 to the clock unit 31. Then, a clock signal CLK3 is generated in the clock unit 31, and the clock signal CLK3 is transmitted to the data input / output unit 24. Further, the clock signal CLK 3 is transmitted from the data input / output unit 24 to the voltage monitoring unit 21. Here, the frequency of the clock signal CK2 is lower than that of the clock signal CK1. Further, the frequency of the clock signal CLK3 is lower than that of the clock signal CLK2, for example, about several tenths.

  Now, when the handset of the external telephone 70 is off-hooked, a switch (not shown) built in the external telephone 70 is turned on, and a closed circuit is formed between the telephone network 60 and the external telephone 70. A current flows to the external telephone 70, and the line voltage VS decreases from the on-hook state. In general, the line voltage VS in the off-hook state is about half of the line voltage VS in the on-hook state. In the normal mode, the line voltage VS is detected by the voltage monitoring unit 21 every predetermined time of 100 msec, for example. If the detected line voltage VS is lower than a predetermined value set in advance, the ASIC 40 determines that the external telephone 70 has been off-hooked. On the other hand, in the power saving mode, the function of the voltage monitoring unit 21 is limited in order to reduce the current consumption, and the fluctuation range ΔVS of the line voltage VS can be detected, but the voltage value of the line voltage VS is set. It cannot be detected. Therefore, when the external telephone 70 is off-hooked in the power saving mode, the modem unit 30 notifies the ASIC 40 of the return to the normal mode triggered by the voltage monitoring unit 21 detecting the voltage fluctuation range ΔVS that is equal to or greater than the specified value. To do.

  The transition characteristics of the line voltage VS in the power saving mode in the conventional FAX apparatus 1 are shown in FIG. In the on-hook state, since the circuit is not closed, no current flows, and the line voltage VS is substantially equal to the power supply voltage VL. Here, the power supply voltage VL is a voltage value applied from the telephone line network 60 to the line connection terminal 11. The conventional FAX apparatus 1 does not include the photocoupler 14 and the capacitor 15. For this reason, when the external telephone 70 is off-hooked at the time t1, the line voltage VS decreases and becomes the voltage VLext at the time t2. The voltage VLext is determined by the power supply voltage VL, the resistance value of the feed resistance of the telephone network 60, and the resistance value of the resistance of the external telephone 70. Next, when the external telephone 70 is on-hooked at time t3, the line voltage VS becomes the power supply voltage VL again. Here, the voltage monitoring unit 21 is set to detect a fluctuation range ΔVS that is equal to or greater than the specified value X. That is, when the line voltage VS becomes equal to or lower than the voltage VL-X, the voltage monitoring unit 21 detects the fluctuation range ΔVS. The specified value X is 20V, for example. This value is a voltage that can detect that the external telephone 70 is off-hook when the power supply voltage VL is 48V. This is because when the power supply voltage VL is 48V, the voltage VLext is about half, ie, about 24V. That is, the fluctuation range ΔVS is 24V, which is equal to or greater than the specified value X. However, when the power supply voltage VL is low, for example, 24V, the voltage VLext is about half, ie, about 12V. That is, the fluctuation range ΔVS is 12V and does not exceed the specified value X. For this reason, it does not become the voltage VL-X or less that the voltage monitoring unit 21 can detect. FIG. 2 shows a case where the power supply voltage VL is as low as 24V, for example. In addition, when the power supply voltage VL is low, a load such as a distributor or a TA is connected between the telephone network 60 and the FAX apparatus 1 when used in a country other than Japan where the power supply voltage VL is set low. There are cases.

  Next, returning to FIG. 1, the circuit operation of the embodiment when the external telephone 70 is off-hook will be described. Hereinafter, a case where the positive electrode side of the power supply voltage VL is connected to the terminal 11A and the negative electrode side is connected to the terminal 11B will be described as an example. Further, it is assumed that the negative side voltage is the ground voltage.

  When the external telephone 70 is off-hooked, the circuit is closed and current flows. That is, a current flows through a path that passes through the terminal 11A, the node N1, the terminal 12A, the external telephone 70, the terminal 12B, the light emitting diode 14b, the node N2, and the terminal 11B. Then, the light emitting diode 14b emits light. The phototransistor 14a of the photocoupler 14 receives the light from the light emitting diode 14b, and the phototransistor 14a is turned on. At this time, no charge is accumulated in the capacitor 15. For this reason, when the phototransistor 14a is turned on, the transmission path 13A is connected to the first electrode of the capacitor 15 and is short-circuited to the transmission path 13B via the capacitor 15 in which charge is not accumulated. As a result, the voltage of the line voltage VS, which is the voltage between the transmission paths 13A and 13B, temporarily decreases to near the ground voltage.

  The transient characteristic of the line voltage VS in the embodiment is shown in FIG. The case where the supply voltage VL is 24 V, which is the same as the conventional example shown in FIG. The line voltage VS in the on-hook state is the power supply voltage VL. When the external telephone 70 is off-hooked at time t4, the line voltage VS temporarily decreases to near the ground voltage, and eventually becomes the voltage VLext. Then, when the external telephone 70 is on-hooked again at time t6, it returns to the voltage VL again.

  At time t5, the line voltage VS becomes VL-X, and the voltage monitoring unit 21 can detect the fluctuation range ΔVS that is the specified value X. When the voltage monitoring unit 21 detects the fluctuation range ΔVS that is the specified value X, the detection signal is transmitted to the modem unit 30 via the data input / output unit 24 and the transformer 18. When the modem unit 30 receives the detection signal, the modem unit 30 transmits a return notification to the ASIC 40. When the ASIC 40 receives the return notification, the ASIC 40 returns from the power saving mode to the normal mode. Details will be described later. When the phototransistor 14a is turned off in the on-hook state, the capacitor 15 is discharged through a current path (not shown).

  Next, the circuit operation of the embodiment when the polarity of the power supply voltage VL is reversed will be described with reference to FIG. The polarity of the supply voltage VL supplied to the line connection terminal 11 may be changed depending on the type of the exchange.

  When the external telephone 70 is off-hooked, the circuit is closed and current flows. That is, a current flows through a path that passes through the terminal 11B, the node N2, the light emitting diode 14c, the terminal 12B, the external telephone 70, the terminal 12A, the node N1, and the terminal 11A. Then, the light emitting diode 14c emits light. The phototransistor 14a of the photocoupler 14 receives the light from the light emitting diode 14c, and the phototransistor 14a is turned on. For this reason, when the phototransistor 14a is turned on, the transmission path 13A is short-circuited with the first electrode of the capacitor 15, whereby the voltage of the transmission path 13A temporarily rises to near the supply voltage VL. As a result, a voltage fluctuation greater than the specified value X occurs in the line voltage VS.

  Next, switching processing from the normal mode to the power saving mode and from the power saving mode to the normal mode will be described. 4 and 5 are flowcharts of processing performed by the ASIC 40. FIG. 6 is a flowchart of processing performed by the modem unit 30.

  First, the flowchart shown in FIG. 4 will be described. When the FAX apparatus 1 is powered on, processing is started in the normal mode. Further, a power saving mode return flag and an external telephone off-hook flag described later are turned off. The ASIC 40 outputs the clock signal CK1 from the clock generation unit 42 to the clock unit 31 of the modem unit 30 (S2). Next, the image forming unit 46 and the image reading unit 47 start driving (S4). Next, it is determined whether or not the external telephone off-hook flag is turned on (S6). The external telephone off-hook flag is a flag indicating a usage state of the external telephone 70. If the external telephone off-hook flag is on, the external telephone 70 is off-hook and indicates that it is in use. Further, if the external telephone off-hook flag is off, it indicates that the external telephone 70 is on-hook and not used. In response to determining that the external telephone off-hook flag is on (S6: YES), the display unit 48 displays that the external telephone 70 is in use (S8), and turns off the external telephone off-hook flag. Then, the process proceeds to step S12. On the other hand, in response to determining that the external telephone off-hook flag is off (S6: NO), normal mode processing (S10) is performed, and the process proceeds to step S12. Here, the normal mode process (S10) is a process of performing FAX transmission / reception.

  In step S12, it is determined whether the ASIC 40 has received a power saving mode transition instruction (S12). The power saving mode transition instruction is, for example, a signal transmitted to the ASIC 40 by operating the operation unit 45 when the user wants to switch to the power saving mode. In response to determining that the power saving mode transition instruction has been received (S12: YES), the process proceeds to step S14. On the other hand, in response to determining that the power saving mode transition instruction has not been received (S12: NO), the process returns to step S10 and normal mode processing (S10) is performed. In step S14, the power saving mode return flag is turned off (S14). In addition, the power saving mode shift instruction is transferred to the modem unit 30. Here, the power saving mode return flag is a flag used to determine whether or not the ASIC 40 returns from the power saving mode to the normal mode. Next, the clock signal transmitted to the clock unit 31 of the modem unit 30 is switched from the clock signal CK1 to the clock signal CK2 having a low frequency (S16). Next, the image forming unit 46 and the image reading unit 47 are stopped. Next, power saving mode processing is performed (S20).

  The power saving mode process is shown in FIG. First, it is determined whether or not there is a return notification transmitted from the modem unit 30 (S32). In response to determining that there is a return notification (S32: YES), since the external telephone 70 is in use, the external telephone off-hook flag is turned on (S34), and the process proceeds to step S36. In response to determining that there is no return notification (S32: NO), since the external telephone 70 is not used, it is determined whether a FAX reception signal has been received (S38). When the FAX apparatus 1 receives a FAX reception signal, the semiconductor DAA 20 first receives the FAX reception signal, and the received FAX reception signal is transmitted to the ASIC 40 via the modem unit 30. In response to determining that the FAX reception signal has been received (S38: YES), the process proceeds to step S36. On the other hand, in response to determining that the FAX reception signal is not received (S38: NO), it is determined whether or not the operation panel of the operation unit 45 is operated (S40). In response to determining that the operation panel 45 of the operation unit 45 has been operated (S40: YES), since it is determined that the user performs FAX transmission, a return instruction is transmitted to the modem unit 30, and the process proceeds to step S36. . On the other hand, in response to determining that the operation panel 45 of the operation unit 45 has not been operated (S40: NO), since it is determined that the user does not perform FAX transmission, the process proceeds to step S22 shown in FIG. In step S36, in order to return from the power saving mode to the normal mode, the power saving mode return flag is turned on (S36).

  Returning to FIG. 4, in step S22, it is determined whether or not the power saving mode return flag is turned on. In response to determining that the power saving mode return flag is turned on (S22: YES), the process returns to step S2 to return to the normal mode. On the other hand, in response to determining that the power saving mode return flag is turned off (S22: NO), the process returns to step S20 to continue the power saving mode.

  Next, a flowchart of processing performed by the modem unit 30 shown in FIG. 6 will be described. This is performed in parallel with the flowchart performed by the ASIC 40 shown in FIGS. Steps S56, S60, S64, and S72 are performed in conjunction with steps S2, S12, S16, and S32 performed by the ASIC 40 shown in FIGS. The processing procedure shown in the flowchart is stored in hardware.

  When the FAX apparatus 1 is turned on, processing is started. First, normal mode writing is performed in a register (not shown) built in the modem unit 30 (S52). In the modem unit 30, the normal mode or the power saving mode is written to the register. Then, the following processing is performed according to the mode written in the register.

  It is determined whether or not the power saving mode is written in the register (S54). When it is determined that not the power saving mode but the normal mode is written in the register (S54: NO), the clock signal CLK2 is transmitted to the semiconductor DAA 20. This process is performed in response to the output of the clock signal CK1 performed by the ASIC 40 in step S2 (FIG. 4). Next, the line voltage VS detected by the voltage monitoring unit 21 of the semiconductor DAA 20 is obtained every predetermined time (S58). The voltage monitoring unit 21 detects the line voltage VS in synchronization with the clock signal CLK2 every predetermined time. The modem unit 30 and the ASIC 40 perform the following processing not shown in FIGS. The modem unit 30 transmits the acquired line voltage VS to the ASIC 40. The ASIC 40 monitors the received line voltage VS, determines that the external telephone 70 has been off-hooked in response to determining that the line voltage VS has dropped below a predetermined voltage, and turns on the external telephone on-hook flag. To do.

  Next, it is determined whether or not there is a power saving mode transition instruction from the ASIC 40 (S60). This process is performed in conjunction with step S12 (FIG. 4). That is, the ASIC 40 transfers the power saving mode shift instruction to the modem unit 30 in response to determining that the power saving mode shift instruction has been received (S12: YES). When receiving the power saving mode transition instruction, the modem unit 30 determines that there is a power saving mode transition instruction (S60: YES). In response to determining that there is an instruction to shift to the power saving mode (S60: YES), the power saving mode is written to the register (S62). Next, in order to switch to the power saving mode, the process returns to step S54. On the other hand, in response to determining that there is no instruction to shift to the power saving mode (S60: NO), the process returns to step S56 in order to continue the normal mode.

  On the other hand, when it is determined that the power saving mode is written in the register (S54: YES), the clock signal CLK3 having a frequency lower than that of the clock signal CLK2 is transmitted to the semiconductor DAA 20 (S64). ). This process is performed in response to the output of the clock signal CK2 performed by the ASIC 40 in step S16 (FIG. 4). Next, the semiconductor DAA 20 determines whether or not the fluctuation range ΔVS of the specified value X or more is detected (S66). The voltage monitoring unit 21 of the semiconductor DAA 20 transmits a detection signal to the modem unit 30 when detecting the fluctuation range ΔVS of the specified value X or more. Therefore, when the modem unit 30 receives the detection signal, the semiconductor DAA 20 determines that the fluctuation range ΔVS of the specified value X or more is detected (S66: YES). In response to determining that the semiconductor DAA 20 has detected the fluctuation range ΔVS that is equal to or greater than the specified value X (S66: YES), the external telephone 70 is in use and the process proceeds to step S72 to return to the normal mode. .

  In step S72, a return notification is first transmitted to the ASIC 40 in order to return to the normal mode. In response to this processing, in step S32 (FIG. 5), the ASIC 40 determines that there is a return notification from the modem unit 30. Next, the process proceeds to step S74. On the other hand, in response to determining that the semiconductor DAA 20 has not detected the fluctuation range ΔVS equal to or greater than the specified value X (S66: NO), it is determined whether a return instruction is transmitted from the ASIC 40 (S70). This process is performed in response to step S40 (FIG. 5). That is, the ASIC 40 transmits a return instruction to the modem unit 30 in response to the determination that the user performs FAX transmission. In response to determining that the return instruction has been transmitted (S70: YES), the process proceeds to step S74 in order to return to the normal mode. On the other hand, in response to determining that the return instruction has not been transmitted (S70: NO), the process returns to step S64 in order to continue the power saving mode.

  In step S74, the clock signal CLK2 is transmitted to the semiconductor DAA 20. Next, the normal mode is written to the register (S76), and the process returns to step S54 to return to the normal mode.

  Here, the transmission paths 13A and 13B are an example of a pair of first connection lines. The transmission paths 13C and 13D are an example of a pair of second connection lines. The telephone connection terminal 12 is an example of a pair of external telephone connection elements. The voltage monitoring unit 21 is an example of a voltage detection circuit. The semiconductor DAA 20 is an example of a data access unit. The light emitting diodes 14b and 14c are examples of current detection elements. The phototransistor 14a is an example of a switch element. The ASIC 40 is an example of a control unit. The detection signal is an example of a transition signal.

As mentioned above, according to above-mentioned embodiment, there exist the following effects.
The FAX apparatus 1 includes a line connection terminal 11, a telephone connection terminal 12, a semiconductor DAA 20, a modem unit 30, and a photocoupler 14. The line connection terminal 11 includes terminals 11A and 11B and can be connected to the telephone line network 60. The semiconductor DAA 20 has a voltage monitoring unit 21. The voltage monitoring unit 21 is connected to the terminals 11A and 11B of the line connection terminal 11 via transmission paths 13A and 13B, respectively. In addition, a fluctuation of the voltage between the transmission paths 13A and 13B that exceeds the specified value X is detected. The semiconductor DAA 20 transmits / receives signals to / from the telephone line network 60 via the line connection terminal 11. The telephone connection terminal 12 includes terminals 12A and 12B, and an external telephone 70 can be connected to the telephone line network 60. The terminal 12A of the telephone connection terminal 12 is connected to the transmission path 13A via the transmission path 13C. The terminal 12B of the telephone connection terminal 12 is connected to the transmission path 13B via the transmission path 13D. The modem unit 30 is connected to the semiconductor DAA 20 and modulates and demodulates signals transmitted and received through the semiconductor DAA 20. The photocoupler 14 includes a phototransistor 14a and light emitting diodes 14b and 14c. The light emitting diodes 14b and 14c are provided in the transmission path 13D. In response to the off-hook of the external telephone 70 connected to the telephone connection terminal 12, the light emitting diode 14b or 14c detects a current flowing through the transmission path 13D. The phototransistor 14a is provided between the transmission paths 13A and 13B, and conducts between the transmission paths 13A and 13B in response to detection of a current by the light emitting diode 14b or 14c. The modem unit 30 can transition between a normal mode in which power is supplied to the modem unit 30 and a power saving mode in which power supply to the modem unit is suppressed compared to the normal mode. The voltage monitoring unit 21 detects a fluctuation that is greater than or equal to the specified value X by the conduction of the phototransistor 14a. The semiconductor DAA 20 transmits a detection signal instructing the modem unit 30 to transition from the power saving mode to the normal mode by detecting the fluctuation of the voltage monitoring unit 21.

  Thereby, the light emitting diodes 14b and 14c detect the current flowing through the transmission paths 13C and 13D when the external telephone 70 connected to the telephone connection terminal 12 is off-hooked. When the phototransistor 14a conducts between the transmission paths 13A and 13B due to the flowing current, the voltage between the transmission paths 13A and 13B becomes zero, so the voltage monitoring unit 21 inevitably has a fluctuation of the specified value X or more. Will be detected. Since the semiconductor DAA 20 can transmit a signal for instructing the modem unit 30 to transition from the power saving mode to the normal mode, the FAX apparatus 1 can return from the power saving mode.

  Further, a capacitor 15 connected in series with the phototransistor 14a is provided between the transmission paths 13A and 13B.

  Thereby, since the capacitor 15 is connected in series with the phototransistor 14a, the terminals of the capacitor 15 are connected between the transmission paths 13A and 13B in response to the conduction of the phototransistor 14a, and charging of the capacitor 15 is started. Is done. As a result, the voltage between the transmission paths 13A and 13B changes from the original voltage before the phototransistor 14a becomes conductive to a lower voltage, and then returns to the original voltage again after the capacitor 15 is charged. Presents voltage fluctuations. The voltage monitoring unit 21 can detect a transient voltage fluctuation from the original voltage to a low voltage. Further, after the capacitor 15 is charged, no current flows between 13A and 13B even if the phototransistor 14a is in a conductive state. Even after detecting the required voltage fluctuation, current does not continue to flow and current consumption does not increase.

  The light emitting diodes 14b and 14c emit light in response to current flowing. The phototransistor 14a is turned on by the light emission of the light emitting diodes 14b and 14c.

  Thereby, the current flowing through the transmission paths 13C and 13D can be detected by the light emitting diodes 14b and 14c and the phototransistor 14a provided in the photocoupler 14, and the voltage between the transmission paths 13A and 13B can be changed. By adding an electronic component called the photocoupler 14, it is possible to realize a configuration that reliably detects the off-hook of the external telephone 70.

  The photocoupler 14 includes light emitting diodes 14b and 14c. The light emitting diode 14b is provided in the transmission path 13D. The light emitting diode 14c is connected in parallel to the light emitting diode 14b, the anode is connected to the cathode side of the light emitting diode 14b, and the cathode is connected to the anode side of the light emitting diode 14b.

  Thus, the line connection terminal 11 can be connected in either the positive or negative direction with respect to the positive / negative voltage of the line voltage of the telephone line network 60. As a result, the positive and negative polarities of the voltages applied to the transmission paths 13A and 13B may be reversed, and the direction of the current flowing through the transmission paths 13C and 13D may be reversed accordingly. By providing the light emitting diodes 14b and 14c in a state of being connected in parallel, the current flowing through the transmission paths 13C and 13D can be detected regardless of the direction of connection to the telephone network 60.

  Further, the modem unit 30 transmits the clock signal CLK2 to the semiconductor DAA 20 in the normal mode, and at a frequency lower than the frequency of the clock signal CLK2 to the semiconductor DAA 20 in the power saving mode. A certain clock signal CLK3 is transmitted. The semiconductor DAA 20 detects the voltage value between the transmission paths 13A and 13B by the voltage monitoring unit 21 while the clock signal CLK2 is transmitted from the modem unit 30, and periodically at a predetermined interval based on the clock signal CLK2. The voltage value is transmitted to the modem unit 30. Further, while the clock signal CLK3 is being transmitted from the modem unit 30, the voltage monitoring unit 21 detects whether or not the voltage fluctuation between the transmission paths 13A and 13B exceeds the specified value X.

  As a result, in the normal mode, it is necessary not only to see the off-hook state of the external telephone 70 but also to see whether the line is connected or disconnected. Therefore, in the normal mode, the voltage value is periodically transmitted to the modem unit 30 at a predetermined interval based on the clock signal CLK2, thereby confirming whether the line is connected or disconnected. On the other hand, in the power saving mode, it is not necessary to regularly check the voltage value regularly from the viewpoint of power saving. Therefore, the semiconductor DAA 20 is driven by the clock signal CLK3 having a frequency lower than that of the clock signal CLK2, and the voltage monitoring unit 21 detects whether or not the voltage fluctuation between the transmission paths 13A and 13B exceeds the specified value X. By doing so, power saving can be achieved.

  Further, the FAX apparatus 1 includes an ASIC 40 and a display unit 48. When the ASIC 40 receives a detection signal from the power saving mode transmitted from the modem unit 30 with the reception of the detection signal from the semiconductor DAA 20 by the modem unit 30, the ASIC 40 notifies the display unit 48 of the external telephone 70. To indicate that is in use.

  As a result, when the external telephone 70 enters an off-hook state, the telephone network 60 is occupied by the external telephone 70, so that the external telephone 70 is in use on the display unit 48 of the FAX apparatus 1. By displaying, it is possible to notify the user who uses the FAX apparatus 1 that the telephone line network 60 is occupied.

Needless to say, the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the spirit of the present invention.
In the embodiment, the case where the ASIC 40 includes the CPU 41 has been described as an example, but the present invention is not limited to this. A plurality of CPUs may be provided, or only an ASIC may be included.

DESCRIPTION OF SYMBOLS 1 Facsimile apparatus 11 Line connection terminal 12 Telephone connection terminal 13A, 13B, 13C, 13D, 13E Transmission path 14 Photocoupler 14a Phototransistor 14b, 14c Light emitting diode 15 Capacitor 16 Diode bridge 17 Switch 18 Transformer 20 Semiconductor-ized DAA
21 Voltage monitoring unit 22 Line signal receiving circuit 23 Line signal sending circuit 24 Data input / output unit 30 Modem unit 31 Clock unit 40 ASIC
41 CPU
42 Clock generator 43 ROM
44 RAM
45 operation unit 46 image forming unit 47 image reading unit 48 display unit 60 telephone line network 70 external telephones N1 and N2 nodes

Claims (6)

A pair of line connection terminals connectable to the telephone line network;
A voltage detection circuit that is connected to each terminal of the pair of line connection terminals via a pair of first connection lines, and that detects a fluctuation of a voltage between the pair of first connection lines that exceeds a specified value; A data access unit that transmits and receives signals to and from the telephone line network via the line connection terminal;
A pair of terminals capable of connecting an external telephone to the telephone line network, each terminal being connected to the pair of first connection lines via a pair of second connection lines; ,
And connected to said data access unit, a modem unit that performs modulation and demodulation of signals transmitted and received via the data access unit,
A current detection element for detecting a current flowing through the pair of second connection lines in response to the off-hook operation of the external telephone connected to the pair of external telephone connection terminals;
A switch element provided between the pair of first connection lines and conducting between the pair of first connection lines in response to detection of a current by the current detection element;
With
The modem unit is
A normal mode in which power is supplied to the modem unit, said power saving mode the normal power supply to the modem unit as compared to the mode is suppressed, be capable of transitioning between,
The voltage detection circuit includes:
Detecting a variation above the specified value by the conduction of the switch element,
The data access unit
A transition signal for instructing a transition from the power saving mode to the normal mode to the modem unit by detecting the variation of the voltage detection circuit;
Facsimile device. The facsimile apparatus according to claim 1,
A facsimile apparatus comprising a capacitor connected in series with the switch element between the pair of first connection lines. The facsimile apparatus according to claim 1 or 2,
The current detection element is a light emitting element that emits light in response to a current flow,
The switch element is a phototransistor that conducts by light emission of the light emitting element,
A facsimile apparatus in which the light emitting element and the phototransistor constitute a photocoupler. The facsimile apparatus according to claim 3,
The light emitting element is
A first light emitting diode and a second light emitting diode;
The first light emitting diode is provided in a current path flowing through the pair of second connection lines,
The second light emitting diode is connected in parallel to the first light emitting diode, the anode is connected to the cathode side of the first light emitting diode, and the cathode is connected to the anode side of the first light emitting diode.
Facsimile device. The facsimile apparatus according to any one of claims 1 to 4,
The modem unit is
In the normal mode, a first operation clock signal is transmitted to the data access unit, and in the power saving mode, the frequency is lower than the frequency of the first operation clock signal to the data access unit. A second operating clock signal that is
The data access unit
While the first operation clock signal is transmitted from the modem unit, a voltage value between the pair of first connection lines is detected by the voltage detection circuit, and at a predetermined interval based on the first operation clock signal. periodically transmit said voltage value to the modem unit,
While the second operation clock signal is transmitted from the modem unit, the voltage detection circuit detects whether or not the voltage variation between the pair of first connection lines exceeds the specified value.
Facsimile device. A facsimile apparatus according to any one of claims 1 to 5,
In addition,
A control unit;
A display unit;
With
The controller is
With the reception of the transition signal from the data access unit by the modem unit, upon receiving a return notification from the power saving mode to be transmitted from the modem unit, to the display unit, the External phone A facsimile machine that indicates that it is in use.

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