JP4516935B2 - Antenna switching system for mobile communication terminals - Google Patents

Description

  The present invention relates to an antenna switching system in which antenna gain switching is simple and easy when an information processing apparatus including a personal computer performs a plurality of types of wireless communication using a portable communication terminal.

  As an apparatus using a conventional portable communication terminal antenna switching system, for example, JP 2001-268007 A (Patent Document 1) discloses a system using a charging cradle capable of short-range communication.

  The outline of this system will be described with reference to FIGS. Here, a personal computer (hereinafter abbreviated as a personal computer) 4 is connected to a charging cradle 102 with a cable 3, and the charging cradle 102 has an antenna 6 connected to a short-range wireless device. Therefore, the personal computer 4 can use the short-range radio by the charging cradle 102. The charging cradle 102 further has a function of mounting other portable wireless terminals 101 such as a mobile phone and a portable wireless radio, for example. When the portable wireless terminal 101 is charged and there is no commercial power supply, the personal computer 4 It has a function to supply power. However, although the built-in antenna 5 of the portable wireless terminal 101 is small and the received signal level cannot be denied, there is no mechanism for switching the antenna.

  What can be conceived for this improvement is a method in which the portable wireless terminal switches the internal antenna to the external antenna. For example, Japanese Patent Laid-Open No. 2001-24785 (Patent Document 2) discloses a mobile phone that enables connection to an in-vehicle antenna of an automobile without increasing the number of external connection terminals.

  The outline of this system will be described with reference to FIG. Here, when the mobile communication terminal 111 is attached to the in-vehicle adapter 112, the antenna 113 of the in-vehicle adapter 112 and a charging circuit (not shown) are drawn into the mobile communication terminal 111 via the contact terminals. When the mobile communication terminal 111 is completely attached to the in-vehicle adapter 112, the connection confirmation of the attachment is detected by infrared communication between the infrared devices 114 and 115 included in both of them. The mobile communication terminal 111 activates the SW (changeover switch) 7 by this detection, switches the internal antenna 5 to the antenna 113 installed in the automobile connected to the in-vehicle adapter 112, and guides the received signal to the radio circuit. As a result, a signal with a high electric field level can be received by the radio circuit of the mobile communication terminal 111. However, in the portable communication terminal of Patent Document 2, the charging cradle is an in-vehicle adapter, and only avoids an increase in the number of external connection terminals when using the charging function of the portable communication terminal and improving the reception sensitivity. It is. That is, a large antenna such as an automobile antenna is assumed, and this charging cradle does not have an antenna. Furthermore, the transmission / reception data of the mobile communication terminal is input / output to / from an AV (Audio Visual) device intended for audible and visible.

  In the above-described conventional technology, the cradle of Patent Document 1 incorporates a radio circuit for short-range radio. However, when the on-vehicle adapter of Patent Document 2 is applied to this cradle, Since switching is performed using the electric field strength of the vehicle-mounted antenna, antenna switching is performed to enable reliable and easy switching of antennas that support multiple types of wireless communication required for mobile communication terminals connected to personal computers including mobile phones. The structure containing the instructions is not explained or suggested.

JP 2001-268007 A JP 2001-24785 A

  The problem to be solved is to support multiple types of wireless communication required for connected mobile communication terminals, even though mobile communication terminals that can be directly connected to a portable PC are connected via a cradle The structure including the antenna switching for enabling the switching of the antenna to be performed reliably and easily is not presented.

  The antenna switching system for a mobile communication terminal according to the present invention is configured such that when a mobile communication terminal having a built-in antenna is attached to a cradle having an external antenna and communicates with a personal computer (hereinafter referred to as a personal computer) connected to the cradle. A system for switching an antenna to the external antenna, and in order to solve the above-mentioned problem, the personal computer sends an antenna selection switching instruction to the mobile communication terminal when connection with the mobile communication terminal is confirmed The mobile communication terminal includes a control unit that receives the selection switching instruction and a built-in antenna switching unit that switches between the built-in antenna and the external antenna under the control of the control unit. Also, the connection confirmation between the personal computer and the mobile communication terminal can be performed by normal exchange of commands predetermined in advance.

  Since it has such a configuration, an instruction to switch from the built-in antenna to the external antenna in the mobile communication terminal can be made by the user manually selecting the antenna to be used from the personal computer, and by changing the setting from the personal computer, It is also possible to automatically select based on normal exchange of commands.

  The cradle includes a control unit that receives a selection switching instruction of the personal computer, and an external antenna switching unit that switches between the plurality of external antennas and selects one under the control of the control unit. Can perform a selection switching operation by normal exchange of a predetermined command between the personal computer and the cradle. Thereby, a plurality of external antennas can be configured with dedicated antennas based on the radio type.

  In such a case, a communication command is predetermined between the personal computer and the mobile communication terminal, and the switching selection unit identifies the radio circuit type by mutual communication with the mobile communication terminal, and It is preferable that a selection switching instruction can be transmitted. Furthermore, it is possible to control a plurality of external antennas by giving a diversity system function to the control unit.

  The portable communication terminal includes a circuit for drawing an external antenna of the cradle and a coupling detection unit for confirming a reliable connection with the cradle, and the built-in antenna switching unit is connected to the coupling detection unit. The internal antenna can be switched to the external antenna when it is detected and detected. With this configuration, the built-in antenna is automatically switched to the external antenna installed in the cradle when it is attached to the cradle and connected to a personal computer. The

  In addition, the use of a USB (Universal Serial Bus) hub and a USB terminal for connection between the cradle and the portable communication terminal allows the portable communication terminal to be directly coupled to a personal computer and allows uniform use of the terminals. It is preferable because it is convenient. Furthermore, since there is no projecting part other than the USB terminal on the contact surface, a device for confirming the connection by contacting the coupling portion that fixes and holds the cradle and the mobile communication terminal is provided on both the personal computer and the cradle. It is desirable because it can be installed without any problem. This coupling device can be an infrared device that confirms connection by sending and receiving infrared rays through contact between the cradle and the portable communication terminal. Further, the cradle may include a charging circuit that receives a commercial power source for charging and charges the personal computer to be connected and the portable communication terminal to be attached.

  The antenna switching system of the mobile communication terminal of the present invention, when the mobile communication terminal is mounted on the cradle connected to the personal computer, because the personal computer is instructed to switch the internal antenna of the mobile communication terminal to the external antenna mounted on the cradle. There is an advantage that the antenna can be selected by the user, and switching of antennas corresponding to a plurality of types of wireless communication included in each mobile communication terminal can be easily and reliably performed.

  When the mobile communication terminal is attached to the cradle and connected to the personal computer, the coupling detection means detects and outputs the coupling between the infrared devices of the infrared device to which voltage is supplied. It is possible to switch the built-in antenna to an external antenna even if it is not.

  When a mobile communication terminal is attached to a cradle connected to a personal computer, the personal computer is designed to make it easy to select the antenna corresponding to the multiple types of wireless communication that each mobile communication terminal has. When a connection to the mobile communication terminal is confirmed, the mobile communication terminal is provided with a switching selection section that sends an antenna selection switching instruction, and the mobile communication terminal switches the antenna under the control of the control section that receives the selection switching instruction. This is realized by including a built-in antenna switching unit. Wireless communication includes telephones, data, broadcasts, etc. used by individuals. Since personal computers have AV functions such as speakers and displays, the user can receive wireless signals received by the mobile communication terminal from the selected antenna. The antenna can be selected by checking with the AV function. Hereinafter, embodiments will be described with reference to the drawings. However, as long as the above functions are not impaired, the configuration can be freely changed by division / merging, and the following description does not limit the present invention. . The relative dimensions shown on the drawings do not match due to partial expansion or the like. Also, some of them are omitted from the drawing even if they are essential in terms of operation functions.

  A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a bird's eye view showing an embodiment of a configuration of an antenna switching system for a portable communication terminal according to the present invention.

  As shown in the figure, the mobile communication terminal 1 is mounted on a cradle 2 and connected to a personal computer (hereinafter abbreviated as a PC) 4 with a USB cable 3. The mobile communication terminal 1 has a built-in antenna 5, and the cradle 2 has an external antenna 6. The mobile communication terminal 1 has a USB terminal 11 and an infrared coupling portion 12, is inserted into the mounting hole 13 of the cradle 2, and a circuit is coupled at the bottom of the mounting hole 13. The USB terminal 11 connects an electric circuit with the cradle 2. The infrared coupler 12 detects the completion of connection by exchanging infrared rays with the cradle 2. The USB terminal 11 of the mobile communication terminal 1 can be directly attached to the USB hub 17 of the PC 4 while being attached to the cradle 2. At that time, the infrared coupling portion 12 for confirming the mounting does not become an obstacle to the mounting because there is no protruding portion.

  The cradle 2 further has a USB hub 14 and is coupled to a USB terminal 15 at one end of the USB cable 3. By connecting the USB terminal 16 at the other end of the USB cable 3 to the USB hub 17 of the personal computer 4, the mobile communication terminal 1 can communicate with the personal computer 4.

  The personal computer 4 has a manual operation input means by a user such as a keyboard and a screen touch panel, and a screen display output means such as a display. In addition to normal functions, the personal computer 4 can communicate with the mobile communication terminal 1 and the cradle 2. Has a program. Details will be described later.

  FIG. 2 is a diagram showing characteristics in the antenna switching system of the portable communication terminal according to the present invention shown in FIG. 2, SW (switch) 7 that is the built-in antenna switching means is added to the mobile communication terminal 1 of FIG. 1, and a built-in wireless circuit unit 8 and control unit 9 are shown. In addition, the PC 4 shows a switching selection unit 10 as a functional block. As shown in the figure, when the mobile communication terminal 1 is fixedly connected to the cradle 2, the control unit 9 performs a reliable and stable connection through normal exchange of commands set in advance with the switching selection unit 10. Is confirmed. Therefore, the switching selection unit 10 can communicate with the radio circuit unit 8 via the control unit 9 and can know the radio circuit type.

  On the other hand, when receiving an instruction from the switching selection unit 10, the control unit 9 controls the SW 7 to switch the built-in antenna 5 to the external antenna 6, and the external antenna 6 is connected to the radio circuit 8. The radio circuit unit 8 converts the radio signal received from the external antenna 6 and sends it from the control unit 9 to the PC 4 via the cradle 2 and the USB cable 3. As a result, the PC 4 can perform wireless communication using the wireless circuit unit 8 connected to the external antenna 6. Since the PC 4 can output the received signal with the AV function, for example, the user can instruct the switching selection unit 10 to switch the external antenna 6 to the built-in antenna 5. Of course, a function for the PC 4 to automatically select an antenna by program control may be added. Since the wireless circuit unit 8 is changed depending on the type of the mobile communication terminal 1, the PC 4 can execute reliable wireless communication corresponding to the type. One external antenna 6 can correspond to various radio systems by a general-purpose antenna.

  FIG. 3 is a diagram showing a detailed embodiment of the mobile communication terminal 1 and the cradle 2 described above. In FIG. 3, in addition to the wireless circuit unit 8 and the control unit 9 described above, the mobile communication terminal 1 further includes an HPF (High Pass Filter) 21, a coupling detection unit 22, and a power supply unit 23. The cradle 2 includes a USB hub 31, an infrared coupling unit 32, an HPF 33, and a charging unit 34. When the mobile communication terminal 1 and the cradle 2 are coupled through the mounting hole 13 shown in FIG. 1, the USB terminal 11 is fitted into the USB hub 31 and the infrared coupling unit 12 is in contact with the infrared coupling unit 32. The USB hub 14 of the cradle 2 is fitted and coupled to the USB terminal 15 of the USB cable 3.

  The HPF 21 has a capacitor C1 and an inductor L1, and the capacitor C1 sends a radio signal received from the cradle 2 to the SW7, while the inductor L1 blocks transmission to the internal circuit. Also, the DC power supply VCC received from the cradle 2 is sent to the internal circuit via the inductor L1, while the supply to the SW7 is blocked by the capacitor C1. The wireless circuit unit 8 is a transmission / reception circuit for wireless communication owned by the mobile communication terminal 1. The control unit 9 controls the functional operation of the mobile communication terminal 1 by a program-controlled processor and memory. The coupling detection unit 22 detects the coupling with the infrared coupling unit 32 from the infrared coupling unit 12 and notifies the control unit 9 of the coupling. The power supply unit 23 is configured by a battery or the like, and supplies power to each circuit that operates when the mobile communication terminal 1 is carried.

  The USB hub 31 is coupled to the USB terminal 11 of the mobile communication terminal 1 by fitting. The infrared coupling unit 32 is supplied with the power supply VCC from the PC 4 via the USB hub 14 and enables transmission of infrared rays to the infrared coupling unit 12. The HPF 33 has a capacitor C2 and an inductor L2, and sends a radio signal received from the external antenna 6 to the mobile communication terminal 1 via the capacitor C2, while the inductor L2 blocks transmission to the internal circuit. Further, the power supply VCC received from the USB 14 is sent to the portable communication terminal 1 via the inductor L2, while the supply to the external antenna 6 is blocked by the capacitor C2. Therefore, the DC power supply VCC connected to the PC 4 and supplied from the USB hub 14 can charge the battery of the power supply unit 23 of the mobile communication terminal 1 by fitting the USB hub 31 and the USB terminal 11. The related circuit may be well known.

  Hereinafter, the operation function of the system according to the present invention will be described with reference to FIG. 3 and FIG. Assume that the mobile communication terminal 1 uniquely defines control commands and the like with the PC 4.

  First, when the mobile communication terminal 1 is directly attached to the USB hub 17 of the PC 4 shown in FIG. 1, the USB terminal 11 is fitted to the USB hub 17. In this state, the voltage VCC received via the USB terminal 11 is supplied to the inside of the mobile communication terminal 1 via the inductor L1 of the HPF 21, and the radio signal received by the built-in antenna 5 is transmitted from the SW 7 to the radio circuit unit 8 and the control unit 9. Via the USB terminal 11 and sent to the PC 4. As a result, the PC 4 can receive the radio signal from the mobile communication terminal 1 and can directly control the control unit 9. In the case of this direct attachment, since there is no infrared coupling at the infrared coupling unit 12, the coupling detection unit 22 does not detect the coupling. Therefore, the control unit 9 does not receive the combination notification from the combination detection unit 22, and therefore does not control the SW7. Thereby, even when this portable communication terminal 1 is directly attached to a general PC, unnecessary control to the control unit 9 can be avoided.

  Next, a case where the mobile communication terminal 1 and the cradle 2 are combined while the cradle 2 is connected to the PC 4 by the USB cable 3 will be described. At this time, by transmitting and receiving infrared rays between the infrared coupling units 32 and 12, the coupling detection unit 22 detects reliable coupling and notifies the control unit 9. In response to this notification, the control unit 9 sends a signal indicating the completion of coupling to the PC 4. On the other hand, the PC 4 also calls the control unit 9 to confirm the direct completion of connection. Upon confirming the connection completion, the PC 4 sends an antenna switching instruction from the switching selection unit 10. This instruction is based on manual input by the user. However, by changing the setting, the switching selection unit 10 can automatically deliver a switching instruction upon confirming the completion of connection.

  Upon receiving the switching instruction, the control unit 9 of the mobile communication terminal 1 drives the SW 7 to connect the radio circuit unit 8 to the external antenna 6 via the HPFs 21 and 33. As a result, the radio signal received by the external antenna 6 is received by the radio circuit unit 8 and sent from the USB hub 14 to the PC 4 via the USB cable 3 by the control unit 9.

  Here, referring to FIG. 4 and FIG. 2 and FIG. 3 together, the SW7 switching procedure in the control unit 9 of the mobile communication terminal 1 will be described with reference to a flowchart.

  The mobile communication terminal 1 is normally in a retracted state (procedure S1) of the built-in antenna 5 as illustrated by SW7. When the connection detection by the connection detection unit 22 is not detected (NO in step S2) and the control of the PC 4 is not accepted (NO in step S3), the states of steps S1 to S3 are repeated.

  When the procedure S2 is “YES” and the coupling detection unit 22 detects the coupling, the mobile communication terminal 1 is attached to the cradle 2, and therefore the control unit 9 does not receive control from the PC 4 (NO in procedure S4). As long as it is, the SW 7 is controlled to switch the built-in antenna 5 to the external antenna 6 of the cradle 2 (step S5). Here, when the mobile communication terminal 1 is detached from the cradle 2, the coupling detection of the coupling detection unit 22 disappears (YES in step S6), so the control unit 9 controls the SW 7 to pull in the built-in antenna 5. (Procedure S7). That is, it returns to the first procedure S1. When the above step S6 is “NO” and the coupling detection of the coupling detection unit 22 continues, the process returns to step S4 and the subsequent procedures are repeated.

  When the procedure S4 is “YES” and the control is accepted from the PC 4, the control unit 9 controls the switching between the built-in antenna and the external antenna by the SW 7 (procedure S8) under the control of the PC 4. This control is continued until the control unit 9 accepts and disappears the PC4 control (YES in step S9). If “YES” in this step S9 is, for example, when the mobile communication terminal 1 is disconnected from the cradle 2 and the acceptance of PC4 control disappears, there is also disappearance of the connection detection (YES in step S10). Continue. On the other hand, when the PC 4 is disconnected from the cradle 2, the procedure S10 is “NO”, the subsequent procedure returns to the procedure S4, and the subsequent procedure is repeated.

  In addition to defining control commands independently, external antenna connection detection can be performed by changing the profile data from the PC 4 to the control unit 9 using the commands or by implementing hardware switching means. The setting may be such that monitoring is not performed. That is, a known technique can be used in combination. Therefore, the control unit 9 can determine the radio field strength between the external antenna 6 of the cradle 2 and the built-in antenna 5 of the mobile communication terminal 1 and notify the PC 4, and can instruct the appropriate antenna switching from the PC 4. .

  Further, as described above, the control unit 9 is notified by sending and receiving infrared rays between the infrared coupling units 12 and 32 in a hardware manner without using a command from the PC 4, and the control unit 9 receives the notification and switches the SW7. It is possible to drive and switch from the built-in antenna to the external antenna. Therefore, the mobile communication terminal 1 can be connected to a general PC that does not have a special switching control unit program in the PC 4. That is, the mobile communication terminal 1 attached to the cradle 2 is automatically switched from the built-in antenna 5 to the external antenna 6 by connecting to the USB hub 17 of a general PC via the cradle 2.

  Further, although the cradle 2 has been illustrated and described as having one antenna 6, the one antenna may be freely replaceable by fitting as dedicated for various wireless systems. In such a configuration, the determination of the radio field intensity by switching will work effectively for antenna selection.

  On the other hand, the DC power supply VCC is supplied from the PC 4 as the power source + V to the mobile communication terminal 1 through the USB cable 3, the USB hub 14, the inductor L 2 of the HPF 33, and the inductor L 1 of the HPF 21.

  Since such a configuration is adopted, when the mobile communication terminal is mounted on the cradle connected to the personal computer, the built-in antenna is switched to the external antenna mounted on the cradle automatically or under the control of the PC. Yes. For this reason, since the sensitivity of a received signal can be increased by selecting an antenna, there is an effect that the antenna can be easily and reliably switched for a plurality of types of wireless communication that each mobile communication terminal has.

  A second embodiment of the present invention will be described with reference to FIGS.

  FIG. 5 is a block diagram showing an embodiment of a configuration different from the antenna switching system for a mobile communication terminal according to the present invention described above.

  The difference from FIG. 2 is that the cradle 2A has the external antennas 6A and 6B, the external antenna switching unit EXTA-SW 34, the control unit 35, and the charging unit 36, and the PC 4A has the switching selection unit 10A. It is that you are. Here, for the sake of convenience, the control unit 9 will be described separately from the MBL (mobile communication terminal) control unit, and the control unit 35 will be described separately from the CRDL (cradle) control unit.

  In addition to the mobile communication terminal 1, the PC 4A uniquely defines control commands and the like with the cradle 2A. Assume that each of the external antennas 6A and 6B is a dedicated antenna suitable for a radio system. The EXTA-SW 34 pulls in the external antennas 6A and 6B, receives control from the CRDL control unit 35, selects one of the external antennas 6A and 6B, and connects to the SW 7 of the mobile communication terminal 1. The CRDL control unit 35 instructs the EXTA-SW 34 to select one external antenna to be switched and selected by exchanging commands with the PC 4. 10 A of switching selection parts instruct | indicate the external antenna to select to the CRDL control part 35 by a user's manual input.

  The external antennas 6A and 6B may be diversity antennas. The diversity function is realized by joint work between the EXTA-SW 34 and the CRDL control unit 35. In the above description, there are two external antennas, but more external antennas may be provided. Of course, an external antenna installed other than the cradle may be connected.

  The illustrated cradle 2A is also used for charging. The charging unit 36 is equipped with a commercial power supply so as to charge the battery of the power supply unit built in each of the mobile communication terminal 1 and the PC 4.

  In the present invention, the personal computer includes a switching selection unit that sends an antenna selection switching instruction to the portable communication terminal when the connection with the portable communication terminal via the cradle is confirmed, and the portable communication terminal receives the selection switching instruction. And a built-in antenna switching unit that switches the built-in antenna to the external antenna of the cradle under the control of the control unit. With this configuration, when a mobile communication terminal is attached to a cradle that is connected to an information processing device such as a personal computer that does not have a radio circuit, an instruction to switch the built-in antenna of the mobile communication terminal to the external antenna mounted on the cradle from the personal computer. Therefore, it is possible to select an antenna by the user, and it is necessary and indispensable for an information processing apparatus that is capable of surely and easily switching antennas corresponding to a plurality of types of wireless communication included in each mobile communication terminal. Is expected to be applied.

It is explanatory drawing which showed one Embodiment of the antenna switching system of the mobile communication terminal by the bird's-eye view. Example 1 It is explanatory drawing which showed one Embodiment of the antenna switching system of the portable communication terminal at the time of incorporating and connecting the component apparatus of FIG. 1 with the block configuration. Example 1 It is explanatory drawing which showed one Embodiment of the circuit structure in the mobile communication terminal and cradle among the components of FIG. 1 with the circuit and the block. Example 1 FIG. 3 is an explanatory diagram showing, in a flowchart, one embodiment of a SW switching procedure in the control unit of the mobile communication terminal of FIG. Example 1 It is explanatory drawing which showed one Embodiment of the antenna switching system of the portable communication terminal different from FIG. 2 with the block configuration. (Example 2) It is explanatory drawing which showed an example of the cradle of a portable radio | wireless terminal, and a system using the same. FIG. 5 is a configuration explanatory diagram of a system when the constituent devices of FIG. 4 are incorporated and connected. It is explanatory drawing which showed an example of the antenna switching system of a mobile communication terminal.

Explanation of symbols

1 Mobile communication terminal 2, 2A Cradle 3 USB cable 4 Personal computer (PC)
5 Internal antenna 6, 6A, 6B External antenna 7 SW (Built-in antenna switching unit)
8 Wireless circuit unit 9, 35 Control unit 10, 10A Switching selection unit 11, 15, 16 USB terminal 12, 32 Infrared coupling unit 13 Mounting hole 14, 17, 31 USB hub 21, 33 HPF
22 coupling detection unit 23 power supply unit 34 EXTA-SW (external antenna switching unit)
36 Charging part

Claims (5)

In a system in which a portable communication terminal having a built-in antenna is mounted on a cradle having an external antenna and communicates with a personal computer connected to the cradle, the personal computer is switched to the external antenna. When a connection with a communication terminal is confirmed, the mobile communication terminal includes a switching selection unit that sends an antenna selection switching instruction to the portable communication terminal. The portable communication terminal receives a control to receive the selection switching instruction, and receives control of the control unit. And a built-in antenna switching unit that switches between the built-in antenna and the external antenna, and the cradle switches between the control unit receiving a selection switching instruction of the personal computer and the plurality of external antennas under the control of the control unit. and an external antenna switching unit for selecting one, this Antenna switching system of the mobile communication terminal parts antenna switching unit, characterized in that to perform the operation of switching selection by the normal transfer of a predetermined command in mutual with the cradle and the personal computer. 2. The antenna switching system for a mobile communication terminal according to claim 1 , wherein a communication command is predetermined between the personal computer and the mobile communication terminal, and the switching selection unit communicates with the mobile communication terminal. An antenna switching system for a mobile communication terminal, wherein a radio circuit type is identified and an antenna selection switching instruction is transmitted. 2. The antenna switching system for a mobile communication terminal according to claim 1 , wherein a diversity antenna is formed by the external antenna, the control unit, and the external antenna switching unit. 2. The antenna switching system for a mobile communication terminal according to claim 1 , wherein a USB hub and a USB terminal used for connection between the mobile communication terminal and the personal computer are used for connection between the mobile communication terminal and the cradle. An antenna switching system for a mobile communication terminal. 2. The antenna switching system for a mobile communication terminal according to claim 1 , wherein the cradle includes a charging circuit that receives a commercial power supply for charging and charges the personal computer to be connected and the mobile communication terminal to be attached. An antenna switching system for a portable communication terminal.

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