JP5856390B2 - COMMUNICATION DEVICE, ITS CONTROL METHOD, AND PROGRAM - Google Patents

Description

  The present invention relates to a communication device, a control method thereof, and a program.

  Current facsimile apparatuses are sometimes connected to a PBX (Private Branch Exchange), but most of them are connected to a public line network (hereinafter referred to as PSTN (Public Switched Telephone Network)). The facsimile apparatus connected to the PSTN and the apparatus introduced as the PSTN exchange are strictly managed so as to conform to a predetermined technical standard. On the other hand, in recent years, a technology called VoIP (Voice Over Internet Protocol), which transmits and receives voice data using an IP network having a broadband transmission path such as a DSL (Digital Subscriber Line) line or an optical line, has become widespread. Have been doing.

  When a PSTN communication apparatus (hereinafter, described as an example of a facsimile machine) is connected to an IP network and voice communication is performed using VoIP with a telephone connected to the communication apparatus. Has the following problems. For example, an adapter that functions as an interface that converts an audio signal output from the device into a signal in a format suitable for an IP network is required. Such an adapter is generally referred to as a VoIP adapter. Since the adapter connected to the facsimile apparatus is not connected to the PSTN, it is not necessary to satisfy a predetermined technical standard required for connecting to the PSTN.

  When a call signal (hereinafter referred to as a CI (Call Indicator) signal) is sent from the line side to the facsimile apparatus, the facsimile apparatus that detects the CI signal enters an off-hook state automatically or manually by the user. This off-hook state means that the line is captured with a low impedance of about 50 ohms to 500 ohms in terms of DC. Patent Document 1 proposes a communication terminal device that switches to a low impedance in order to capture a direct current line when an off-hook of an external telephone is detected. Also, this DC resistance can be switched from among a plurality of types.

JP 2010-171765 A

  However, the prior art has the following problems. Normally, an exchange arranged on a line stops sending the CI signal when detecting an off-hook state. However, in recent years, VoIP adapters that do not immediately stop sending CI signals have appeared on the market. The facsimile apparatus connected to the VoIP adapter continues to receive the CI signal (hereinafter referred to as a residual CI signal) that should have been stopped for a certain period of time after being off-hooked. This residual CI signal is about 75 Vrms in Japan. Therefore, when the residual CI signal is received in a state where the facsimile apparatus captures DC with low impedance as in the above-described prior art, damage to the DC capturing circuit and its peripheral circuits is great and may cause failure. is there. For example, in the above prior art, there is no concept of switching the DC resistance within a range in which the exchange is determined to be in the off-hook state in order to protect from the residual CI signal. Therefore, if the residual CI signal continues for a long time after the direct current capture, the direct current capture circuit and its peripheral circuits may be damaged due to the influence and cause a failure.

  The present invention has been made in view of the above-described problems, and performs a DC capture with an optimum impedance for communication, protects a circuit from a residual CI signal, and ensures communication reliability. It is an object to provide a control method and a program.

The present invention can be realized as a communication device. The communication apparatus includes: a receiving unit that receives a call signal from a line; a detecting unit that detects a line current of a line captured by a first capturing unit having a first impedance; and the line current detected by the detecting unit determination means for determining whether the condition to be less than the first threshold value exceeds a predetermined time, after capturing the line by said first acquisition means, the line current detected by the detection means by said determining means When the condition to be less than the first threshold value it is determined to have exceeded the predetermined time, and Turkey and a control means for catching the line by the second acquisition means having a second impedance less than said first impedance A communication device. In addition, the communication apparatus includes: a receiving unit that receives a call signal from the line; a detecting unit that detects a line voltage of the line captured by the first capturing unit having a first impedance; and the line that is detected by the detecting unit. A determination unit that determines whether or not a state in which the voltage is equal to or lower than a first threshold has exceeded a predetermined time; and the line detected by the detection unit by the determination unit after the line is captured by the first capture unit Control means for capturing a line by a second capturing means having a second impedance lower than the first impedance when it is determined that the state in which the voltage is equal to or lower than the first threshold exceeds a predetermined time. And

  The present invention can provide a communication apparatus, a control method thereof, and a program for performing DC capture with an optimum impedance for communication, protecting a circuit from a residual CI signal, and ensuring communication reliability.

1 is a block diagram illustrating a configuration example of a facsimile apparatus according to a first embodiment. It is a figure which shows an example of a DC-VI characteristic. It is a figure which shows an example of a DC-VI characteristic. 3 is a flowchart illustrating a processing procedure of the facsimile apparatus according to the first embodiment. It is a figure which shows the CI signal from a line | wire, and the timing of line | wire acquisition control. It is a figure in case an electric current or voltage exceeds a threshold value and a line is opened after line supplementation. It is a figure which shows a mode until a line is open | released after the residual CI signal is not lost. It is explanatory drawing which concerns on 2nd Embodiment. 10 is a flowchart illustrating a processing procedure of the facsimile apparatus according to the second embodiment. 10 is a flowchart illustrating a processing procedure of a facsimile apparatus according to a third embodiment. 10 is a flowchart illustrating a processing procedure of a facsimile apparatus according to a fourth embodiment. 10 is a flowchart illustrating a processing procedure of a facsimile apparatus according to a fifth embodiment. It is a figure which shows an example of a DC-VI characteristic. It is a figure which shows an example of a DC-VI characteristic.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention.

<First Embodiment>
<Overall configuration of facsimile machine>
The first embodiment of the present invention will be described below with reference to FIGS. First, a block configuration of a communication apparatus 100 (here, a facsimile apparatus will be described as an example) 100 according to the present embodiment will be described with reference to FIG. A system on chip (SOC) 101 comprehensively controls the entire system of the facsimile apparatus 100. The CPU in the facsimile apparatus 100 is mounted on the SOC 101. A memory 140 connected to the SOC 101 is a main storage device, and functions as a system work memory for the CPU of the SOC 101 and a memory for storing a control program for executing processing according to the present invention. The memory 140 also functions as a memory for temporarily storing image data and various types of information during facsimile transmission or facsimile reception. The memory 140 stores information set by the user.

  An operation panel 118, a reading unit 121, a recording unit 122, and an interface (IF) unit 123 are further connected to the SOC 101. The operation panel 118 includes a display 119 and keys 120, which function as a user interface. The display device 119 performs display related to the device status and menu. The keys 120 are keyboards such as buttons and numeric keys for receiving input of various instructions from the user. The user can input user setting information using these keys.

  The reading unit 121 reads an image from a document and generates image data. The generated image data may be transmitted by facsimile to the other apparatus via the communication line 130 or may be printed on a recording medium by the recording unit 122. The interface (IF) unit 123 functions as an interface when various information devices are connected from the outside. The modem 102 is a modem that is connected to the SOC 101 and operates based on control by the SOC 101. Specifically, the modem 102 performs modulation processing using the image data read by the reading unit 121 that is a target of facsimile transmission, and demodulation processing of a signal received via the communication line 130. The modem 102 is connected to the SDAA (that is, silicon DAA) 104 through the insulating element 103.

  The SDAA 104 is an example of a network control unit and is a semiconductor NCU (network control unit). The SDAA 104 is a network control device that is connected to the communication line 130 and functions as an interface between the facsimile apparatus 100 and an external public line (communication line) 130. Also, the SDAA 104 controls the connection (capture) state of the line when communicating with the counterpart device via the communication line 130. The communication line 130 is also connected to a telephone 128 externally attached to the facsimile apparatus 100 via a connection terminal (connection unit) 129. The telephone 128 is connected to the communication line 130 via the connection terminal 129 and the H relay 110, and the SDAA 104 is connected to the communication line 130 in parallel with the telephone 128. The SDAA 104 not only captures the line and controls the communication when performing facsimile transmission / reception, but also when the telephone 128 performs voice communication with the other apparatus via the communication line 130. Control the capture state. The SDAA 104 executes these controls based on the control of the SOC 101.

  The SDAA 104 controls the DC capture state of the line using the line capture unit 105. The direct current impedance when the direct current is captured by the line capturing unit 105 is variable. This impedance is obtained by being controlled by a preset current characteristic with respect to a DC voltage (hereinafter referred to as a DC-VI characteristic).

  The voltage detector 150 monitors the voltage on the line. The current detection unit 151 monitors the current on the line. The DC capturing circuit 152 is a peripheral circuit of the SDAA 104 configured by transistors and the like, and is a circuit that is used to adjust the DC impedance under the control of the SDAA 104 while performing DC capturing. It is also used to create a line open state or to send a dial pulse, which is one type of selection signal for the line.

  The rectifier circuit 155 is composed of a diode bridge or the like, and rectifies a signal from the line and transmits it to the SDAA 104 side. The reception IF circuit 153 is an interface circuit for receiving a facsimile reception signal received via the communication line 130. For example, in the case of Japan, the AC impedance matching circuit 154 adjusts the AC impedance to 600 ohms. This is a circuit for adjusting the AC impedance during communication.

  The noise removal circuit 156 is a circuit that suppresses lightning surge, electromagnetic noise, and the like from the communication line 130, and conversely prevents noise from the facsimile apparatus 100 being transmitted via the communication line 130. CI detection circuit 108 is connected to communication line 130 and detects a paging signal (hereinafter referred to as “CI signal”) received from the communication line. When the CI detection circuit 108 detects a CI signal from the communication line, it transmits a CI detection signal 109 indicating that to the SOC 101. The SOC 101 can determine whether or not a CI signal is received from the communication line 130 based on the CI detection signal 109.

  The H relay 110 is a circuit for connecting an external telephone 128 connected via the hook detection circuit 117 to the DC power supply 113 or the communication line 130. The H relay 110 is an example of a switching unit, and performs switching between a connection state in which the external telephone 128 is connected to the communication line 130 and a disconnection state in which the communication line 130 is disconnected. The H relay 110 is controlled by the SOC 101 using the H relay drive signal 111. As shown in FIG. 1, when the telephone is disconnected from the communication line 130 by the H relay 110, the telephone does not ring even when a CI is received. The so-called no-sound incoming state of the facsimile apparatus 100 is set.

  The DC power supply 113 is a circuit that supplies current to the hook detection circuit 117. The hook detection circuit 117 is an example of a detection unit, and is connected to the telephone 128 and is a circuit that detects an off-hook or on-hook of the telephone 128. Hook detection circuit 117 transmits the off-hook or on-hook detection result of telephone 128 to SOC 101 using hook detection signal 114. The SOC 101 can determine the state of the hook in the telephone 128 based on the hook detection signal 114. The hook detection circuit 117 detects the current flowing through the telephone 128 both when connected directly to the communication line 130 by the H relay 110 and when connected to the DC power supply 113. Thereby, the hook detection circuit 117 detects an off-hook or on-hook state in the telephone 128.

  The pseudo CI transmission circuit 116 is a circuit that transmits a pseudo CI signal to the telephone 128. The pseudo-CI signal is a signal sent to the telephone 128 in order to ring the telephone 128 that is disconnected from the line when a CI incoming call is received from the partner apparatus via the communication line 130. is there. The pseudo CI transmission circuit 116 transmits a pseudo CI signal to the telephone 128 in response to a transmission instruction by the pseudo CI drive signal 115 from the SOC 101.

  In the present embodiment, the facsimile machine 100 is connected to the VoIP adapter 124 via the communication line 130. The VoIP adapter 124 performs PCM encoding or the like on a transmission signal of a facsimile or telephone having a voice band frequency of 300 to 3400 Hz and transmits it to an IP network using a protocol such as SIP. In this embodiment, an output signal from the VoIP adapter 124 is transmitted to the IP network of the optical network 127 via the broadband router 125 and the line termination device 126 as an example. On the other hand, the VoIP adapter 124 converts the signal received from the optical network 127 into a facsimile or telephone signal having a voice band frequency of 300 to 3400 Hz. Further, the signal is transmitted to the facsimile machine 100 via the communication line 130. The VoIP adapter 124 has a function of recognizing a dial pulse from an input signal or recognizing hooking or the like in the telephone 128 attached to the facsimile apparatus 100. This VoIP adapter is generally called a terminal adapter (hereinafter referred to as TA), and is a kind of adapter for connecting a telephone or a facsimile apparatus to a digital line.

<DC impedance adjustment by line capture unit>
Next, with reference to FIGS. 2 and 3, a DC-VI characteristic curve representing a DC voltage-current characteristic in the case of performing DC capture selected for facsimile communication will be described. Each graph shows a voltage value on the vertical axis and a current value on the horizontal axis. 201 in FIG. 2 is an example of a DC-VI characteristic in which the impedance is high when the line current is small and the impedance is low when the line current is large. For example, when the line current is 20 mA, the direct current resistance is about 900Ω, but when the line current is 120 mA, the apparent direct current resistance is about 167Ω. Reference numeral 202 denotes a DC-VI characteristic example in which the DC resistance is about 300Ω regardless of the line current.

  FIG. 3 shows an example of the DC-VI characteristic in which the resistance value is made higher overall or locally than in FIG. 301 is a DC-VI characteristic example in which the direct current resistance value increases as the current increases. For example, when the current is 120 mA, the direct current resistance is about 200Ω, but when the current is 200 mA, the direct current resistance is about 1 KΩ. 302 has a large DC resistance of about 1 KΩ regardless of the line current.

<Line capture control>
Next, with reference to FIG. 4, a processing procedure relating to line capture control of the facsimile apparatus according to the present embodiment will be described. The process described below is realized by the SOC 101 reading out and executing a control program stored in the memory 140. In the following, a description will be given of control for a residual CI signal that is received after the acquisition of a line when a CI signal is received.

  First, in S601, when the CI detection circuit 108 detects a CI signal from the line side, the automatic reception operation is started, and the SOC 101 starts the DC line acquisition by controlling the DC acquisition circuit 152 by the line acquisition unit 105 of the SDAA 104. To do. Subsequently, in S602, the SOC 101 selects a DC-VI characteristic that increases the DC impedance when DC is captured. Here, as shown by 302 in FIG. 3, regardless of the upper limit of the line current, a DC-VI characteristic having an overall impedance higher than 202 (hereinafter referred to as high impedance (first impedance)) is selected. Note that, as indicated by 301, a DC-VI characteristic in which impedance is locally increased at a portion where the line current is high may be selected. According to the present embodiment, by selecting a DC-VI characteristic having a high impedance when direct current is captured as described above, the direct current capture circuit and its peripheral circuits are damaged by the influence of the residual CI signal, and the cause of the failure Reduce the possibility of becoming.

  Next, in S603, the line capturing unit 105 captures the line according to the selected DC-VI characteristic. Subsequently, in S604, the SOC 101 starts a timer, and measures an elapsed time after capturing the line. In S605, the SOC 101 uses the time measured in S604 and the current or voltage on the line detected after line supplementation, and the detection result is equal to or lower than a preset threshold value 1 (first threshold value or less). It is determined whether or not the state is continued for a certain time. Here, it is determined whether or not the generation of the CI signal from the line side is stopped despite the line supplement, that is, whether or not the generation of the residual CI signal is completed within a predetermined time. Here, if the detection result is equal to or smaller than the threshold value 1 for a predetermined time, the process proceeds to S612, and if the detection result exceeds the threshold value 1, the process proceeds to S606. The threshold will be described later.

  In S606, the SOC 101 detects the current or voltage on the line after supplementing the line, and determines whether or not the detection result is equal to or greater than a preset threshold value 2 (second threshold value or more). The threshold value 2 is set to a higher current or higher voltage than the threshold value 1. If the detection result is greater than or equal to the threshold 2, the process proceeds to S607, and if it is less than the threshold 2, the process proceeds to S608. In S607, the SDAA 104 releases the line because the current or voltage has reached the threshold value 2 or more in S606. The line is opened in order to prevent the SDAA 104 and peripheral circuits from being damaged by the residual CI signal. Thereafter, in S620, the history as an error end, that is, the date and time, and information indicating the phenomenon that the residual CI has been confirmed for a certain time or more are stored in the memory, and the processing is ended.

  On the other hand, in S608, the SOC 101 determines whether or not the generation of the residual CI signal exceeding the threshold value 1 has not ended and the time during which the residual CI signal exceeding the threshold value 2 has not been generated has passed for a certain period of time. After a certain time has elapsed, the process proceeds to S609, and before the certain time has elapsed, the process returns to S605. In S609, the SOC 101 stops the timer started in the predetermined time S604. Subsequently, in S610, the SDAA 104 releases the line. Further, in S611, the SOC 101 stores the history, that is, the date and time, and information indicating the phenomenon that the residual CI signal has been confirmed for a certain time or more in the memory as the error end, and ends the process.

  On the other hand, if it is determined in S605 that the detection result has been in a state where the detection result is equal to or less than the threshold value 1 for a certain period of time, the SOC 101 ends the generation of the residual CI signal and controls the DC-VI characteristics to the normal state in S612. Specifically, the SOC 101 selects a low impedance (second impedance) DC-VI characteristic indicated by 202. When connected to a public line, the DC-VI characteristic is selected according to the technical standards of the terminal equipment connected to the public line. In other words, if the DC-VI characteristic of a terminal device connected to a VoIP adapter or the like whose technical standards are not clear is determined to be off-hook, the communication is successful even if the VoIP adapter is determined to be off-hook. Sometimes it goes. However, when a connection is made where a technical standard such as a public line is clearly defined, it must be controlled to have a DC-VI characteristic that matches the technical standard. For this purpose, the DC-VI characteristics are changed in S612. Here, instead of 202, a low-impedance DC-VI characteristic may be used when the current is locally high, such as 201. Subsequently, in S613, the SOC 101 stops the timer, ends the current and voltage monitoring, and ends the residual CI signal processing.

  Next, with reference to FIGS. 5 to 7, the CI signal from the line and the timing of line acquisition control according to the present embodiment will be described. 5 to 7, the horizontal axis indicates time, and the vertical axis indicates line voltage. First, the timing of line acquisition control according to this embodiment will be described with reference to FIG.

  When the CI signal appears on the line, as shown in S602 above, the CI detection circuit 108 detects it, and the line capture unit 105 performs line capture with high impedance. Here, the voltage detector 150 or the current detector 151 monitors the voltage or current on the line. The SOC 101 detects the voltage or current on the line via the insulating element 103 and the modem 102. When the voltage or current exceeds a predetermined threshold value 1, the SOC 101 determines that residual CI exists on the line. Here, the presence or absence of the residual CI signal may be determined based on a high current or voltage value, that is, only the threshold value 1, or the current or voltage value written as threshold value 1 ′ instead of the threshold value 1 decreases. The threshold at may also be used. Depending on the sampling timing in monitoring the current and voltage of the residual CI signal, a positive peak may not be obtained. Therefore, it is also effective to detect that a residual CI signal is generated due to a drop in current or voltage when the voltage or current swings to the negative side.

  Alternatively, when the difference between the threshold value 1 and the threshold value 1 'is large, it may be determined that the residual CI signal is generated. The presence or absence of a residual CI signal is determined based on the threshold value 1 or the difference between the threshold value 1 and the threshold value 1 ′, and if the residual CI signal is determined not to be for a certain period, the line acquisition unit 105 is shown in FIG. 5 and S612. In this way, control is performed to obtain a normal impedance line. Here, the amplitude AA of the residual CI signal is a level larger than the difference between the threshold 1 and the threshold 1 '. FIG. 5 shows that there is no residual CI signal that should appear in the section A when the residual CI signal is generated. In contrast, in FIG. 7, the residual CI signal is also generated in the section A.

  FIG. 6 shows a state in which the current or voltage exceeds the threshold value 2 in S606 and goes to the line opening in S607 after the line supplementation in S603. Here, instead of the threshold value 2, a threshold value in a direction in which the current or voltage is reduced, which is written as the threshold value 2 ′, may be used. When the difference between the threshold value 2 and the threshold value 2 ′ is large, the residual CI It may be determined that a signal is present. When the residual CI signal is large and may damage the SDAA 104 and its peripheral circuit, in this embodiment, the line is opened in S607 to prevent the influence on the SDAA 104 and the peripheral circuit. Here, the amplitude BB of the residual CI signal is a level larger than the difference between the threshold 2 and the threshold 2 '.

  FIG. 7 shows that despite the high-impedance line acquisition (S602), the residual CI signal does not disappear, the determination in S605 is NO in the determination of the threshold 1 for a certain time, and a certain time has passed (YES in S608). The state where the SDAA 104 opens the line (S610) is shown. As described above, when the residual CI signal remains continuously for a certain period or longer, the SDAA 104 opens the line to prevent the influence on the SDAA 104 and peripheral circuits.

<Second Embodiment>
Next, the line acquisition control according to the second embodiment will be described with reference to FIGS. FIG. 8 shows how the line impedance is set to be high impedance when connected to the VoIP adapter in the determination of S1101 in the flowchart of FIG. 9 described later. That is, in this embodiment, it is confirmed whether or not the facsimile apparatus is connected to the VoIP adapter, and if it is connected, the high impedance is maintained even after the residual CI signal is not generated.

  In the flowchart shown in FIG. 9, the same steps as those in the flowchart shown in FIG. That is, in the following, the process of S1101 will be described. Note that the processing described below is realized by the SOC 101 reading and executing a control program stored in the memory 140.

  When the generation of the residual CI signal is stopped, in S1101, the SOC 101 confirms the setting of the facsimile apparatus 100 indicating whether or not the facsimile apparatus 100 is connected to the VoIP adapter, and determines whether or not the setting is the VoIP adapter. . That is, if the user setting is the connection line TA (terminal adapter) setting, the process proceeds to S613, where the high impedance is maintained, and if not, the process proceeds to S612, where the normal impedance is restored.

  As described above, when the facsimile apparatus is not connected to the public line, it is not always necessary to capture the line with the impedance according to the technical standard for connecting the public line. Therefore, in the flowchart of FIG. 9, it is possible to pass the control of changing to the normally used DC-VI characteristic.

<Third Embodiment>
Next, line acquisition control according to the third embodiment will be described with reference to FIG. The present embodiment is an example in the case where so-called retry is performed in which line acquisition is performed again after exiting S611 of FIG. 9 described in the second embodiment. In FIG. 10, S1201 is equivalent to S601, and S1203 to S1220 are equivalent to S603 to S620 of FIG. Therefore, S1202 will be described below. Note that the processing described below is realized by the SOC 101 reading and executing a control program stored in the memory 140.

  When the line is captured with the high impedance DC-VI characteristic, it may be possible that off-hook detection cannot be performed depending on the VoIP adapter. For this reason, in the present embodiment, following the process of S611 in FIG. 9, the process starts from S1201 as a retry process. In S1202, the SOC 101 has a DC-VI characteristic used in normal communication, for example, an impedance higher than 202 but lower than the impedance (302) selected in the previous line acquisition (S602) (1502, FIG. 13). 3rd impedance) is selected. Thereby, an off-hook can be detected by the VoIP adapter. Therefore, the mismatch of the DC-VI characteristics selected in S602 in FIG. 9 can be corrected.

  Reference numeral 1502 in FIG. 13 is an example of an impedance lower than the impedance selected in S602. The resistance value, i.e., the direct current impedance is made higher than that of 202, and the resistance value, i.e., the direct current impedance is made lower than 302 in general or locally. Reference numeral 1601 in FIG. 14 shows an example in which an impedance higher than 202 and lower than 301 is set locally at a part where the line current is high, for example, 200 mA. DC-VI characteristics such as 1601 may be used instead of 1502. Here, the threshold value 1 and the threshold value 2 may be changed from the threshold value 1 or the threshold value 2 in FIG.

<Fourth Embodiment>
Next, line acquisition control according to the fourth embodiment will be described with reference to FIG. The present embodiment is an example in the case where so-called retry is performed in which line acquisition is performed again after exiting S620 of FIG. 9 described in the second embodiment. In FIG. 11, only S1302 is different from that in FIG. 10, and the other steps are the same as those in the flowchart in FIG. If the high impedance selected in S602 is not sufficiently high and may be damaged by the residual CI signal, it is corrected. Note that the processing described below is realized by the SOC 101 reading and executing a control program stored in the memory 140.

  In order to perform line acquisition again after exiting S620 of FIG. 4 or FIG. 9, the process starts from S1201 as a retry process. In S1302, the SOC 101 selects the DC-VI characteristic so that the impedance (1602, fourth impedance) is higher than that of the previous line acquisition (S602). Reference numeral 1602 in FIG. 14 shows an example of a DC-VI characteristic in which the overall resistance value, that is, the direct current impedance is made lower than 302. Reference numeral 1601 denotes an example of the DC-VI characteristic in which the resistance value, that is, the direct current impedance is locally lower than that of 301. Thereby, according to this embodiment, the mismatch of the DC-VI characteristic selected by S602 can be corrected. Instead of 1602, a DC-VI characteristic such as 1601 in which the resistance value, that is, the direct current impedance is locally lowered may be used.

<Fifth Embodiment>
Next, line acquisition control according to the fifth embodiment will be described with reference to FIG. In this embodiment, the line acquisition control is performed by changing the impedance in S1402 which is shifted from S609 without performing the line release in S610 of FIG. 12, S601 to S620 are equivalent to FIG. 9, and S1403 to S1420 are equivalent to S604 to S620 of FIG. Note that the processing described below is realized by the SOC 101 reading and executing a control program stored in the memory 140.

  After stopping the timer in S609, in S1402, the SOC 101 is higher than the DC-VI characteristic used in normal communication, for example, 202, but higher than the impedance (302) selected in the previous line acquisition (S602). A low impedance (1502 in FIG. 13, third impedance) is selected. Thereafter, the process proceeds to S1403, and the SOC 101 starts a timer. As a result, when the impedance is changed, the line can be captured without damaging the SDAA 104 and its peripheral circuits while changing the line capture impedance at the first incoming call by not releasing the line.

<Other embodiments>
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

Claims (15)

Receiving means for receiving a call signal from the line;
Detecting means for detecting the line current of the line captured by the first capturing means having the first impedance;
Determination means for determining whether or not a state in which the line current detected by the detection means is equal to or less than a first threshold exceeds a certain time ;
When it is determined by the determination unit that the line current detected by the detection unit is equal to or less than a first threshold after the line is acquired by the first acquisition unit, the first time is exceeded. communication device comprising a Turkey and a control means for catching the line by the second acquisition means having a second impedance less than the impedance. The control means includes
When it is determined by the determination means that the state in which the line current detected by the detection means is equal to or less than a first threshold exceeds a certain time, the line captured by the first acquisition means is released. The communication apparatus according to claim 1 . The control means includes
Upon detection of the line current over a higher second threshold value than the first threshold value by said detecting means, to claim 1 or 2, characterized in that for opening the line that captured by the first capture means The communication device described. The capturing means includes
When it is determined that the state in which the line current detected by the detection unit is less than or equal to a first threshold value exceeds a predetermined time in the previous line acquisition, the second impedance is lower than the first impedance and the second The communication apparatus according to claim 2 , wherein the line is captured by a third capturing unit having a third impedance higher than the impedance. Wherein, when detecting the line current of more higher second threshold value than the first threshold value by said detecting means in the previous line capture in response to receipt of the call signal, from the first impedance 4. The communication apparatus according to claim 3 , wherein the line is captured by a fourth capturing means having a higher fourth impedance. The communication device is a facsimile device;
The control means includes
Even if it is determined by the determination means that the state in which the line current detected by the detection means is equal to or less than the first threshold exceeds a certain time , the facsimile apparatus is connected to the VoIP adapter. the communication device according to any one of claims 1 to 5, characterized in that to maintain the use of the first catching means having a first impedance. Receiving means for receiving a call signal from the line;
  Detecting means for detecting the line voltage of the line captured by the first capturing means having the first impedance;
  Determining means for determining whether or not a state in which the line voltage detected by the detecting means is equal to or lower than a first threshold exceeds a certain time;
  When it is determined that the state in which the line voltage detected by the detecting unit is equal to or lower than a first threshold after the line is captured by the first capturing unit exceeds a predetermined time, the first impedance Control means for capturing a line by means of a second capturing means having a lower second impedance than
A communication apparatus comprising: The control means includes
  When it is determined by the determination means that the state where the line voltage detected by the detection means is equal to or lower than a first threshold exceeds a certain time, the line captured by the first acquisition means is released. The communication apparatus according to claim 7, characterized in that: The control means includes
  9. The circuit according to claim 7, wherein when the line voltage equal to or higher than a second threshold value higher than the first threshold value is detected by the detecting unit, the line captured by the first capturing unit is opened. Communication equipment. The capturing means includes
  When it is determined that the state in which the line voltage detected by the detection unit is equal to or lower than a first threshold value has exceeded a predetermined time in the previous line acquisition, the second impedance is lower than the first impedance. 9. The communication apparatus according to claim 8, wherein the line is captured by a third capturing means having a higher third impedance. When the line voltage equal to or higher than the second threshold value, which is higher than the first threshold value, is detected by the detection means in the previous line acquisition, the control means is more than the first impedance in response to reception of the calling signal. The communication apparatus according to claim 9, wherein the line is captured by a fourth capturing unit having a high fourth impedance. The communication device is a facsimile device;
  The control means includes
  Even when it is determined by the determination unit that the line voltage detected by the detection unit is equal to or lower than the first threshold exceeds a certain time, the facsimile apparatus is connected to the VoIP adapter. The communication device according to claim 7, wherein the use of the first capturing means having the first impedance is maintained. A receiving step for receiving a call signal from the line;
A detection step of detecting a line current of a line captured by a first capturing means having a first impedance;
A determination step of determining whether or not a state in which the line current detected in the detection step is equal to or less than a first threshold exceeds a certain time ;
After capturing the line by said first acquisition means, when the determining the line current which is detected by the detecting step in the step is determined that the condition to be less than the first threshold value exceeds a predetermined time, the first the communication control method according to the second capturing means by said execution to Rukoto a control step of capturing the line having a second impedance less than the impedance. A receiving step for receiving a call signal from the line;
  A detection step of detecting the line voltage of the line captured by the first capturing means having the first impedance;
  A determination step of determining whether or not a state where the line voltage detected in the detection step is equal to or lower than a first threshold exceeds a certain time;
  After the line is captured by the first capturing means, if it is determined in the determination step that the state where the line voltage detected in the detection step is equal to or lower than a first threshold exceeds a certain time, the first impedance A control step of capturing the line by a second capturing means having a lower second impedance;
A method for controlling a communication apparatus, characterized in that: The program for making a computer perform each step in the control method of the communication apparatus of Claim 13 or 14 .

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