JP2010165312A - Entrance/exit management system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an entrance/exit management system capable of avoiding a case where communication between an identification device and a reception device is not established due to a shortage of remaining capacity of an electricity storage means without adding a means for reporting a decrease in the remaining capacity of the electricity storage means to the identification device. <P>SOLUTION: A transmission control unit 8 determines the degree of decrease in the remaining capacity by comparing the remaining capacity of the electricity storage means 6 detected by a remaining capacity detecting unit 7 with a predetermined threshold value. The transmission control unit 8 shortens communicable distance between a communication function unit 3 and the reception device by gradually decreasing transmission power in transmitting a signal to the reception device from the communication function unit 3 when the remaining capacity of the electricity storage means 6 decreases. Thus, when the remaining capacity of the electricity storage means 6 decreases, the distance from the identification device 1 to the reception device shortens when the reception device authenticates identification information of the identification device 1 to unlock a door. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  According to the present invention, when identification information is transmitted from the identification device to the receiving device, the receiving device authenticates the identification information and determines whether to permit entry into or exit from the target area according to the authentication result. This relates to the exit management system.

  2. Description of the Related Art In recent years, entrance / exit management systems using a receiving device disposed at an entrance of a target area such as an office in a building or the like and a thin identification device that can be carried by a user have become widespread. In this entrance / exit management system, identification information is transmitted from the identification device to the receiving device by wireless communication, and the receiving device authenticates the identification information, and whether to permit entry / exit into the target area according to the authentication result. By determining whether or not, the door unlocking operation or the opening / closing operation of the automatic door, automatic ticket gate, etc. is controlled.

  This type of entrance / exit management system generally employs a passive RF tag (passive tag) system in which an identification device has a function of transmitting using the power of a carrier wave transmitted from a receiving device. Therefore, the communicable distance is relatively short, and an act of holding the identification device over the receiving apparatus is required.

  On the other hand, the identification device itself has a battery as a power source, and it is convenient to adopt an active RF tag (active tag) system in which the identification device has a function of transmitting data upon receiving power supply from the battery. It has also been proposed to improve performance. That is, in the identification device provided with its own power supply, the communication distance with the receiving apparatus can be increased (for example, 10 m) as compared with the passive RF tag method. This eliminates the need to hold the identification device over the receiving apparatus, and communication between the receiving apparatus and the identification device is enabled only by a user who has (identifies) the identification device approaching the receiving apparatus.

  By the way, when a primary battery is provided in the identification device, there is a disadvantage that regular maintenance such as battery replacement is required. Therefore, in this type of identification device, a solar cell that converts light energy into electric energy is used as a power source. It is conceivable to use (see, for example, Patent Document 1).

  It is also conceivable that the identification device includes a solar cell as a power source, and a display unit provided on the identification device is driven by electric power generated by the solar cell to display various information on the display unit (for example, a patent). References 2 and 3).

  However, in the case of using a solar cell, if power can be supplied from the solar cell only when light is incident on the solar cell, for example, in an environment where the incident light intensity to the solar cell decreases at night or the like. Communication between the identification device and the receiving device may not be established. Therefore, it is preferable to use a power storage means such as a secondary battery or a capacitor together with the solar battery so that stable power supply is continuously performed even in an environment where the incident light intensity with respect to the solar battery is reduced. That is, according to this configuration, communication between the identification device and the receiving device can be performed by utilizing the electric power stored in the power storage unit even when light is not incident on the solar cell.

JP 2004-24551 A JP 2002-32728 A JP-A-10-240873

  By the way, even if it is an identification device which used a solar cell and an electrical storage means together as mentioned above, when the identification device is used indoors dimly, sufficient light is incident on the solar cell for a long time. When the identification device is used in a state where it is not, the remaining amount of the power storage means gradually decreases. If the remaining amount of the power storage means is insufficient, communication between the identification device and the receiving device may not be established, and the entrance / exit management system may not function normally (the user cannot enter / exit). In this case, if the power storage means is charged by exposing the solar cell to light for a certain period of time, it is possible to prevent communication between the identification device and the receiving device from being established due to a shortage of the remaining power in the power storage means.

  Therefore, a means is provided for notifying the user of a decrease in the remaining capacity of the power storage means by prompting the user when the remaining capacity of the power storage means decreases, and prompting the user to charge the power storage means (an act of exposing the solar cell to light). It is desirable. However, when such a notification means is added to the identification device, the number of parts constituting the identification device increases, the identification device becomes larger and becomes unsuitable for carrying by the user, or the cost of the identification device is low. There is a problem that it becomes difficult.

  The present invention has been made in view of the above reasons, and without adding a means for notifying a decrease in the remaining amount of the power storage means to the identification device, between the identification device and the receiving device due to a shortage of the remaining power in the power storage means. An object of the present invention is to provide an entrance / exit management system capable of avoiding communication failure.

  The invention of claim 1 comprises a receiving device arranged at the entrance and exit of the target area, and an identification device possessed by the user and capable of wireless communication with the receiving device, and when identification information is transmitted from the identification device to the receiving device, An entry / exit management system in which a receiving apparatus authenticates identification information and determines whether to permit entry / exit into the target area according to the authentication result, and the identification device carries the identification information as electrical information An information holding unit that performs wireless communication with the receiving device, a communication function unit that transmits identification information to the receiving device, a solar cell that generates power by receiving light, and a power storage that stores the power generated by the solar cell A power supply unit that supplies driving power to at least the communication function unit, a remaining amount detection unit that detects the remaining amount of the power storage unit, and a remaining amount detected by the remaining amount detection unit is compared with a predetermined threshold value. amount The transmission power at the time of the identification information transmitted by stepwise reduced in the communication function unit to be below the threshold value, and having a transmission control unit to shorten the communicable distance between the receiving device.

  Since the identification device includes a transmission control unit that gradually decreases the transmission power of the communication function unit when the remaining amount detected by the remaining amount detection unit falls below a predetermined threshold, the identification device When the communicable distance between the receiver and the receiving device is shortened, it is possible to know the decrease in the remaining amount of the power storage means. That is, the user can know the decrease in the remaining capacity of the power storage means because the feeling of use of the identification device changes, so that the means for notifying the decrease in the remaining capacity of the power storage means by sound or light is not added to the identification device. The user can be notified of a decrease in the remaining amount of the power storage means. Therefore, when the remaining amount of the power storage means decreases, the user can be urged to charge the power storage means, and as a result, communication between the identification device and the receiving device cannot be established due to a shortage of the remaining power of the power storage means. There is an advantage that it can be avoided.

It is a schematic block diagram which shows the identification device of Embodiment 1 of this invention. It is the schematic which shows the example of application of the entrance / exit management system same as the above. It is a flowchart which shows operation | movement of an identification device same as the above. It is a schematic block diagram which shows an entrance / exit management system same as the above.

(Embodiment 1)
The entrance / exit management system of this embodiment is used for entrance / exit management of a room R as a target space as shown in FIG. 2 and is installed on a wall near the door D of the entrance / exit of the room R. The apparatus 100 and the thin (here, card type) identification device 1 that is carried by the user H and wirelessly communicates with the receiving apparatus 100 are provided as constituent elements.

  In this entrance / exit management system, each individual who owns the identification device 1 is authenticated by performing wireless communication using an electromagnetic wave as a medium between the identification device 1 and the receiving device 100. Depending on the situation, it is decided whether or not to allow entry into and exit from the room.

  That is, the identification device 1 is equipped with an information holding unit 2 (see FIG. 1) in which identification information (ID) for identifying each individual (owner of the identification device 1) is stored as electrical information. The identification information is transmitted to the receiving apparatus 100 during communication with the receiving apparatus 100. The receiving apparatus 100 compares the received identification information with pre-registered data (regular identification information), unlocks the door D if the authentication is successful, and locks the door D if the authentication fails. To control the unlocking operation of the door D. For this reason, if the above entrance / exit management system is used, the user H can manage the entrance / exit of the user H only by holding the identification device 1.

  As shown in FIG. 1, the identification device 1 includes an information holding unit 2 including a memory that stores identification information, a communication function unit 3 that performs wireless communication with the receiving device 100, and power for the communication function unit 3. And a power supply unit 4 for supplying power. The identification device 1 has a function of transmitting at least identification information stored in the information holding unit 2 to the receiving device 100 via the communication function unit 3. Further, the identification device 1 is provided with a remaining amount detection unit 7 and a transmission control unit 8 which will be described later. The information holding unit 2 is not limited to the memory, and may carry identification information represented by, for example, the open / closed state of the contacts of the dip switch.

  The power supply unit 4 supplies power necessary for communication with the receiving device 100, and includes a solar cell 5 that is a photoelectric conversion element that converts light energy irradiated from the outside into electric energy. Therefore, by ensuring an environment in which a sufficient amount of light is applied to the solar cell 5, stable power supply can be realized over a long period of time without performing maintenance such as battery replacement or charging. . Here, it is assumed that the identification device 1 is carried by the user H in a form that can be easily seen by surrounding people, such as a name tag, so that the solar cell 5 can be irradiated with light in a normal usage form of the identification device 1. .

  Further, in the power supply unit 4, the storage unit 6 such as a secondary battery or a capacitor is used together with the solar cell 5, so that the communication function unit 3 can be used even in an environment where the solar cell 5 is not irradiated with light. In this configuration, a stable power supply is continuously performed. According to this configuration, even if no light is incident on the solar cell 5, communication between the identification device 1 and the receiving device 100 can be performed by using the electric power stored in the power storage unit 6. Therefore, the power storage means 6 is charged with the output of the solar battery 5 during the day when the power generation efficiency of the solar battery 5 is high, and the power stored in the power storage means 6 is used at night when the power generation efficiency of the solar battery 5 is reduced. The output of the solar cell 5 can be used effectively.

  Here, the identification device 1 of the present embodiment enables generation of sufficient power by the solar cell 5 not only outdoors where sunlight is irradiated but also indoors (indoors) where the illuminance is lower than that of sunlight. As the solar cell 5, a solar cell 5 having a sensitizing substance and an electron transporting part and a hole transporting part for transporting electric charge is used. A substance with a sensitizing action has the function of distributing electrons (negative charge) and holes (positive charge) to different substances by absorbing light, which is the cause of the development of the photoelectric conversion effect. Become. Here, a material part that receives electrons from a substance having a sensitizing action is an electron transport part, and a material part that receives holes from a substance having a sensitizing action is a hole transport part.

  Examples of the solar cell 5 having a substance having a sensitizing action and a charge transporting portion (electron transporting portion and hole transporting portion) include a dye-sensitized solar cell, a quantum dot-sensitized solar cell, and a dye-sensitized organic solar cell. In this embodiment, a dye-sensitized solar cell is adopted as the solar cell 5. The dye-sensitized solar cell 5 can be configured so as to have transparency as a whole by forming the substrate from a transparent material. Further, if the substrate is formed of a flexible resin film or the like, the whole can be obtained. It is possible to adopt a configuration having flexibility.

  By the way, even if it is the identification device 1 which used the solar cell 5 and the electrical storage means 6 together like this embodiment, when the identification device 1 is used indoors dimly, a solar cell over a long time. When the identification device 1 is used in a state where sufficient light does not enter 5, the remaining amount of the power storage means 6 gradually decreases. If the remaining amount of the power storage unit 6 is insufficient, sufficient power is not supplied to the communication function unit 3 in a state where the solar cell 5 is not irradiated with light, and thus communication between the identification device 1 and the receiving device 100 is not established. The entrance / exit management system may not function normally (the user H cannot enter or leave the room).

  Therefore, in this embodiment, by adopting the configuration described below in the identification device 1, the user H is informed of a decrease in the remaining amount of the power storage means 6 and the power storage means 6 is charged (the action of exposing the solar cell 5 to light). ) To prevent the establishment of communication between the identification device 1 and the receiving device 100 due to a shortage of the remaining amount of the power storage means 6.

  That is, the identification device 1 communicates between the remaining amount detection unit 7 that detects the remaining amount of the power storage unit 6 and the receiving device 100 when the remaining amount of the power storage unit 6 detected by the remaining amount detection unit 7 decreases. And a transmission control unit 8 for changing the state.

  The remaining amount detecting unit 7 detects the remaining amount of the power storage unit 6 when the communication function unit 3 starts communication with the receiving device 100 (when an activation signal described later is received from the receiving device 100). Here, the remaining amount of the power storage unit 6 is detected by monitoring the output voltage of the power storage unit 6, but the remaining amount may be detected by other known methods.

  The transmission control unit 8 determines how much the remaining amount has decreased by comparing the detected remaining amount of the power storage unit 6 with a predetermined threshold. Here, a first threshold value and a second threshold value smaller than the first threshold value are set, and when the remaining amount of the power storage means 6 is equal to or greater than the first threshold value (hereinafter referred to as A level), The remaining amount of the power storage means 6 is judged in three stages: when it is less than the first threshold and greater than or equal to the second threshold (hereinafter referred to as B level) and when it is less than the second threshold (hereinafter referred to as C level). It shall be.

  Here, the transmission control unit 8 supplies power (transmission power) supplied to an antenna (an RF antenna 34 described later) when transmitting a signal from the communication function unit 3 to the receiving device 100 when the remaining amount of the power storage unit 6 decreases. By making it smaller, the communicable distance between the communication function unit 3 and the receiving device 100 is shortened. More specifically, the transmission control unit 8 causes the communicable distance to the receiving device 100 to be gradually reduced as the remaining amount of the power storage unit 6 decreases to the A level, the B level, and the C level. In addition, control for switching the transmission power in three stages is performed. As a result, in a state where the remaining amount of the power storage means 6 is sufficient (A level state), the identification device 1 can transmit identification information to the receiving device 100 from a location relatively distant from the receiving device 100. In a state where the remaining amount of the power storage unit 6 is reduced to some extent (B level or C level state), the distance at which the identification information can be transmitted from the identification device 1 to the receiving device 100 is shortened.

  The operation of the identification device 1 at this time will be described with reference to the flowchart of FIG.

  When the remaining amount of the power storage means 6 is detected by the remaining amount detection unit 7 (S1), the transmission control unit 8 compares the remaining amount with the first and second threshold values. If the detected remaining amount is equal to or greater than the first threshold (S2: Yes), the remaining amount of the power storage means 6 is determined to be A level, and the communicable distance with the receiving device 100 is maximum (here, several m). ) To select the transmission power Pt1 (S4). On the other hand, if the remaining amount is less than the first threshold and greater than or equal to the second threshold (S3: Yes), the remaining amount of the power storage means 6 is determined to be B level, and the transmission power Pt2 smaller than the transmission power Pt1 is selected. (S5), the communicable distance with the receiving apparatus 100 is made shorter than the maximum. If the remaining amount is less than the second threshold (S3: No), the remaining amount of the power storage means 6 is determined to be C level, and the transmission power Pt3 smaller than the transmission power Pt2 is selected (S6). The communicable distance with the apparatus 100 is the minimum (here, several centimeters).

  As a result, when the user H who has the identification device 1 approaches the entrance of the room R, the reception device 100 authenticates the identification information of the identification device 1 and unlocks the door D from the user H. Until the remaining distance of the power storage means 6 decreases. Therefore, when the user H is normally (A level), the door D is unlocked several steps before the door D, and the door D is not unlocked unless it is close to the door D (B level). Alternatively, when a situation occurs (C level) in which the door D is not unlocked unless the identification device 1 is held over the receiving apparatus 100, it is possible to know a decrease in the remaining amount of the power storage means 6 of the identification device 1. In this way, the user H who knows that the remaining amount of the power storage unit 6 has decreased is charged with the power storage unit 6 by exposing the solar cell 5 to light for a while to solve the shortage of the remaining power storage unit 6. It can be avoided that communication between the identification device 1 and the receiving device 100 is not established due to an insufficient amount.

  According to the configuration described above, a change in the feeling of use (that is, the door D is unlocked) in the normal usage pattern of the entrance / exit management system in which the user H has the identification device 1 and enters and exits the room R. It is possible to intuitively know that the remaining amount of the power storage means 6 has decreased with a stepwise change in the distance between the identification device 1 and the receiving device 100 when the power is stored. That is, even if no means (such as LED or buzzer) for notifying that the remaining amount of the power storage means 6 is reduced by sound or light is added to the identification device 1 The user H can be notified to prompt the charging action of the power storage means 6 (the action of exposing the solar cell 5 to light). Therefore, the number of parts constituting the identification device 1 increases due to the addition of notification means for notification by sound or light, and the identification device 1 becomes larger and becomes a size unsuitable for the user H to carry. It can be avoided that the cost reduction of 1 becomes difficult.

  Further, in the configuration in which the identification device 1 notifies the fact by sound or light when the remaining amount of the power storage unit 6 is low, the power for driving the notification unit is consumed when the remaining amount of the power storage unit 6 decreases. As a result, the consumption of the electric power stored in the electric storage means 6 is increased as compared with the normal time (when the remaining amount of the electric storage means 6 is at the A level). Absent. On the contrary, when the remaining amount of the power storage means 6 decreases, the transmission power is reduced and the transmittable distance is shortened. There is an advantage that it can be suppressed.

  Furthermore, in the present embodiment, the remaining amount of the power storage unit 6 is determined in three stages, and the communicable distance with the receiving device 100 in the identification device 1 is gradually reduced as the remaining amount decreases. Therefore, the user H is not only the information that the remaining amount of the power storage unit 6 is decreased from the communicable distance with the receiving device 100 in the identification device 1 but also how much the remaining amount of the power storage unit 6 is decreased. And can take appropriate measures (measures such as charging the power storage means 6 immediately) according to the urgency of the remaining amount.

  Note that the remaining amount of the power storage means 6 may be determined in four or more stages. In this case, the communicable distance with the receiving device 100 in the identification device 1 is also finely switched in four or more stages. Similarly, the remaining amount determination of the power storage means 6 may be performed in two stages of normal and abnormal. In this case, the transmission power is switched in two stages, and the communicable distance is switched in two stages.

  Hereinafter, a specific example of the entrance / exit management system of the above embodiment will be described with reference to FIG.

  The receiving device 100 installed at the entrance of the room R includes an LF band transmission unit 101 and an LF antenna 102 for communicating with the identification device 1 in the first communication method of the LF band (long wave band: 30 to 300 kHz), The RF transceiver 103 and the RF antenna 104, and the LF band transmitter 101 and the RF transceiver 103 for communicating with the identification device 1 in the second communication method of the UHF band (ultra-high frequency band: 300 MHz to 3 GHz) are controlled. A control unit 105, a display unit 106 including a liquid crystal display connected to the control unit 105, and a buzzer 107 are provided. Furthermore, the receiving apparatus 100 includes a storage unit 108 in which identification data for authentication (regular identification information) is stored.

  The identification device 1 possessed by the user communicates with the receiving device 100 by the LF band receiving unit 31 and the LF antenna 32 for communicating with the receiving device 100 by the first communication method, and by the second communication method. For this purpose, the communication function unit 3 includes an RF transmission / reception unit 33 and an RF antenna 34, and a control unit 35 that controls the LF band reception unit 31 and the RF transmission / reception unit 33. Here, the LF antenna 32 is formed of, for example, a loop antenna formed on a substrate (not shown) of the communication function unit 3, and the RF antenna 33 is formed of a patch antenna formed on the substrate.

  Next, an operation example of the above-described entrance / exit management system will be shown.

  The receiving apparatus 100 superimposes and amplifies the activation signal generated by the control unit 105 on the signal component of the induced magnetic field in the LF band transmission unit 101, and transmits the signal from the LF antenna 102 by the first communication method (LF) at a constant cycle. Transmit intermittently. As a result, an authentication area 9 is formed around the receiving apparatus 100 (near the entrance / exit of the room R) within a range where the activation signal reaches.

  When the user H having the identification device 1 enters the authentication area 9, the identification device 1 receives the activation signal from the reception device 100 by the LF antenna 32, and then the LF band reception unit 31 activates the control unit 35. Then, the control unit 35 generates a response signal including the identification information in the information holding unit 2, and receives the response signal from the RF transmission / reception unit 33 via the RF antenna 34 by the second communication method (UHF). Reply to Here, the identification device 1 supplies power from the power supply unit 4 only to the LF band receiving unit 31 in the communication function unit 3 until receiving the activation signal, and other units (RF transmitting / receiving unit 33) other than the LF band receiving unit 31. The controller 35) operates in a low power consumption mode in which no power is supplied to the controller 35), and operates in a normal mode in which power is supplied to each unit other than the LF band receiver 31 for the first time by receiving an activation signal. .

  The receiving apparatus 100 receives the response signal via the RF antenna 104 by the RF transmission / reception unit 103 and collates the identification information included in the response signal with the data in the storage unit 108. When it is determined that the identification information is legitimate identification information and the authentication is normally completed, the control unit 105 of the receiving apparatus 100 transmits a confirmation signal (ACK signal) including the authenticated identification information to the RF signal. The data is transmitted from the transmission / reception unit 103 to the identification device 1 via the RF antenna 104. In addition, the control unit 105 of the receiving apparatus 100 notifies the display unit 106 and the buzzer 107 when the authentication of the identification information is normally completed, and performs control for unlocking the door D at the entrance / exit of the room R. On the other hand, if the authentication of the identification information fails, a warning is given by the display unit 106 and the buzzer 107, and control for maintaining the door D at the entrance of the room R is locked. The other device connected to the receiving device 100 has a part of the function of the receiving device 100 so that the response signal is transferred from the receiving device 100 to the other device, and collation of identification information is performed by the other device. It is good also as a structure to perform.

  When the identification signal is received by the RF transmitter / receiver 33, the identification device 1 ends the transmission of the response signal. Instead of transmitting the confirmation signal from the receiving apparatus 100, the identification information that has been authenticated may be included in the next activation signal. In this case, the identification device 1 receives the activation signal including its own identification information in the LF band. The reception of the response signal is terminated by receiving the signal at the unit 31.

  Thus, the identification device 1 is activated by the activation signal in the LF band and returns a response signal in the UHF band, so that the authentication area 9 can be accurately defined in a range of 1.5 to 2 m, for example. Here, the transmission control unit 8 of the identification device 1 is configured to switch the transmission power of the response signal transmitted from the RF transmission / reception unit 33 via the RF antenna 34 according to the remaining amount of the power storage unit 6. As a result, when the range (authentication area 9) where the response signal reaches in the identification device 1 is switched, the communicable distance with the receiving device 100 in the identification device 1 is switched.

  The RF transmitter / receiver 33 that performs UHF band wireless communication consumes as much as 10 to 20 mA, whereas the LF band receiver 31 that performs LF band wireless communication has a weakness of about several μA. Since the power is activated, the standby power of the identification device 1 can be kept low by adopting a low power consumption mode in which power is not supplied to the RF transmitter / receiver 33 in the standby state.

  In the above-described example, the configuration is shown in which the receiving device 100 controls the unlocking operation of the door D according to the authentication result of the identification information. However, the present invention is not limited to this example, and the receiving device 100 is an automatic door, an automatic ticket gate, or the like. It is good also as a structure which controls opening / closing operation | movement of this. The wireless communication basically means communication using an electromagnetic wave as a medium, but the identification device 1 may perform communication (wireless communication) with the receiving apparatus 100 using electromagnetic induction.

  By the way, if the entrance / exit management system having the above-described configuration is used, for example, a receiving device 100 is installed at the entrance to a management area where an unspecified number of visitors are present, and is identified for legitimate (with appointment) visitors. By passing the device 1 in advance, it becomes possible to identify a legitimate visitor regardless of whether or not he / she is acquainted and permit entry into the management area. Furthermore, in situations where collective action is required in a childcare facility, a nursing facility, etc., it is also possible to use each device for confirming the presence of each individual instead of making a call by carrying the identification device 1 with each individual. .

DESCRIPTION OF SYMBOLS 1 Identification device 2 Information holding part 3 Communication function part 4 Power supply part 5 Solar cell 6 Power storage means 7 Remaining amount detection part 8 Transmission control part 100 Receiving device H User

Claims (1)

A receiving device disposed at the entrance / exit of the target area and an identification device possessed by the user and capable of wireless communication with the receiving device. When the identification information is transmitted from the identification device to the receiving device, the receiving device authenticates the identification information. And an entry / exit management system that determines whether to permit entry / exit in the target area according to the authentication result, wherein the identification device includes an information holding unit that carries identification information as electrical information, and a reception At least a communication function unit including a communication function unit that transmits identification information to the reception device by performing wireless communication with the device, a solar cell that generates power by receiving light, and a power storage unit that stores the power generated by the solar cell A power supply unit that supplies driving power to the battery, a remaining amount detection unit that detects the remaining amount of the storage means, and a remaining amount detected by the remaining amount detection unit are compared with a predetermined threshold value. The transmission power at the time of the identification information transmission in the functional unit by stepwise reduced, entrance and exit management system characterized by having a transmission control unit to shorten the communicable distance between the receiving device.

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