JP2004118488A - Network device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a network device capable of radiocommunication and improvable in security. <P>SOLUTION: A network projector 1 network-connected by wireless LAN connection through a wireless LAN card 24, creates a password including an IP address and transmits the password by projection on a screen 2a or infrared communication by an IrDA (infrared data association) part 23. When a user adds the acquired password to transmit image data to the IP address of the network projector 1, the network projector 1 discriminates the password and displays an image. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a network device connected to a network by wireless communication means.
[0002]
[Prior art]
The network devices connected to the network have communication means, and communication is established by authenticating each other's network devices. Non-Patent Document 1 discloses a conventional network device capable of wireless communication. According to Non-Patent Document 1, the same password is input to a PDA (Personal Digital Assistance) and a PHS (Personal Handyphone System), and a password transmitted from one side is compared on the receiving side to perform authentication. This allows access to the network device of the other party.
[0003]
[Non-Patent Document 1]
Hiroki Tsuboyama, "I tried connecting a Bluetooth SD card and a PHS with a built-in Bluetooth.", [Online], January 17, 2002, ZDNet / JAPAN, [Search August 28, 2002], Internet <URL: http: /// www. zdnet. co. jp / mobile / 0201/17 / n # pbtgbt # 3. html>
[0004]
[Problems to be solved by the invention]
However, according to the above-described conventional network device, when transmitting and receiving a password, the communication distance is about 10 m in the Bluetooth (TM) standard shown in Non-Patent Document 1. Therefore, for example, it is possible to receive a password from an adjacent room across a wall. This allows another person to access the network device using the password received by the other network device. Therefore, there is a possibility that data in the network device may be falsified or leaked, and there is a problem of low security.
[0005]
In addition, the communication distance according to the wireless LAN standard is 50 m to 100 m between network devices that perform communication by wireless LAN. For this reason, a password can be received even from the outdoors, and there has been a problem that security is further reduced.
[0006]
An object of the present invention is to provide a network device capable of wireless communication capable of improving security.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a network device connected to a network by a first communication unit for performing information communication by non-optical wireless communication, wherein a password creation unit for creating a password; And a second communication unit for wirelessly transmitting the password, authenticating the returned password and permitting the operation.
[0008]
According to this configuration, the network device optically wirelessly transmits the password created by the password creation unit by the second communication unit including infrared rays, projection, and the like. The network device authenticates the password returned by another network device and permits the operation. Thus, the network device can be accessed from another network device by the first communication unit.
[0009]
Further, the present invention is characterized in that, in the network device having the above configuration, a password is created by the password creating means when the network device is activated. According to this configuration, each time the network device is started, the previously created password is discarded, and access is not possible unless a new password is used.
[0010]
Further, the present invention is characterized in that, in the network device having the above configuration, the second communication means uses visible light. According to this configuration, the user visually recognizes the password projected on the screen or the like by projection, returns the password to the network device, and is permitted access.
[0011]
Further, the invention is characterized in that the network device having the above-mentioned configuration includes a projector.
[0012]
The present invention also provides a network device that is connected to a network by a first communication unit that performs information communication by non-optical wireless communication, and optically transmits a signal requesting a password for obtaining permission to operate another network device. It is characterized by having a second communication means for wireless transmission.
[0013]
According to this configuration, the network device receives the password request signal for obtaining the access permission by the optical second communication means such as infrared rays. The network device creates a password and sends it to the requester of the password. The user returns the received password to the network device, and the operation is permitted by authenticating the password. Thereby, the network device can be accessed from the network device that transmitted the password by the first communication unit.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing a network projector which is a network device of the first embodiment. The network projector 1 includes a projector unit 2 and a document camera 3.
[0015]
The projector unit 2 has a screen 2a and a projection unit 2b. The projection unit 2b is arranged at the upper center of the screen 2a, and projects an image on the screen 2a. The document camera 3 is arranged in the projection unit 2b and captures an image on the screen 2a. An operation unit 4 for operating the projector unit 2 and the document camera 3 is provided below the screen 2a.
[0016]
FIG. 2 is a block diagram illustrating a configuration of the network projector 1. The projector unit 2 is provided with a CPU 21 that performs various calculations to control the operation of the projector unit 2. A switch 22, an IrDA receiving unit 23, a wireless LAN card 24, a wired LAN card 25, and a driving unit 34 are connected to the CPU 21.
[0017]
A switch 22 including a “password display” button for projecting a password on the screen 2 a is provided in the operation unit 4, and a signal corresponding to a user operation is sent to the CPU 21. The IrDA communication unit 23 communicates a signal of infrared communication according to IrDA (Infrared Data Association) standard. The wireless LAN card 24 performs wireless communication by making a network connection according to the wireless LAN standard. The wired LAN card 25 performs wired communication by making a network connection between devices connected by a LAN cable.
[0018]
In the present embodiment, a password is transmitted and received by the IrDA communication unit 23, and data such as image data is transmitted and received via the wireless LAN card 24 and the wired LAN card.
[0019]
The image memory 29 is composed of a RAM, and stores image data received by a wireless LAN and a wired LAN. The size of the image data can be changed by a scaler 30 connected to the image memory 29. Further, an analog RGB decoder 26 and an NTSC / PAL decoder 27 are connected to the image memory 29 via a progressive conversion unit 28.
[0020]
The analog RGB decoder 26 and the NTSC / PAL decoder 27 are connected to a video device, and receive an analog RGB signal or an NTSC / PAL signal. The analog RGB decoder 26 performs A / D conversion of the analog RGB signal and converts it into a digital video signal. The NTSC / PAL decoder 27 performs A / D conversion of the NTSC / PAL signal and converts it into a digital video signal. The progressive converter 28 converts a digital video signal into a non-interlaced digital image.
[0021]
The display element 33 is connected to the drive unit 34. The display element 33 is composed of a liquid crystal display element, and each pixel of the display element 33 is switched by the driving unit 34 according to the image data received from the image memory 29. The display element 33 is irradiated with each light beam of RGB from the light source 31 via the color separation unit 32. Each light beam passes through the display element 33 and an image is projected on the screen 2a by the projection lens 35.
[0022]
The document camera 3 is provided with a CPU 10 connected to the CPU 21 of the projector unit 2 and performing various calculations to control the operation of the document camera 3. To the CPU 10, a memory 14, a card driver 15, a switch 16, a distance measuring unit 17, a light measuring unit 18, an A / D converting unit 9, a CCD driving unit 11, an aperture driving unit 12, and a lens driving unit 13 are connected.
[0023]
The memory 14 includes a ROM and a RAM, and stores an operation program of the document camera 3 and temporarily stores an operation. The card driver 15 causes the CPU 10 to recognize the memory card 19 and enable connection to the document camera 3. The memory card 19 is made of smart media (R) or the like, and stores image data captured by the document camera 3.
[0024]
A switch 16 including a “shooting” button for taking a picture with the document camera 3 is provided in the operation unit 4, and a signal corresponding to a user's operation is sent to the CPU 10. The distance measuring unit 17 and the photometric unit 18 detect the distance and the amount of light of the screen 2a as a subject. The lens driving unit 13 drives the photographing lens 5 based on the detection result of the distance measuring unit 17. The aperture driving unit 12 drives the aperture 6 based on the detection result of the photometric unit 18.
[0025]
Thus, a subject image is formed on the CCD 7 driven by the CCD driving unit 11. The A / D converter 9 is connected to the CCD 7 via the amplifier 8. The subject image received by the CCD 7 is converted into an electric signal, amplified by an amplifier 8 and A / D converted by an A / D converter 9.
[0026]
In the network projector 1 having the above configuration, when the power of the network projector 1 is turned on, the operation program of FIG. In step # 11 of the operation program, a password is generated and stored in the memory 14 via the CPUs 21 and 10. The password is generated, for example, by generating a random number and combining it with the IP address assigned to the network projector 1.
[0027]
In step # 12, the generated password is projected on the screen 2a by the projection unit 2b. Thus, the user can visually recognize the screen 2a and obtain the password. In step # 13, the process waits for the occurrence of an event. When a predetermined operation is performed by a user, an event occurs and an operation corresponding to each event is performed.
[0028]
A user can operate the network projector 1 with a personal computer (hereinafter, referred to as a “PC”) connected to the network projector 1 via a wireless LAN card 24 via a wireless LAN. The projector projection utility is installed on the personal computer.
[0029]
When the projector projection utility of the personal computer is started, a projector projection screen shown in FIG. 4 is displayed. A password input section 41 is provided on the projector projection screen 40. The user inputs the password projected on the screen 2a into the password input unit 41. When the “Start” button 43 for starting projection is selected with a mouse or the like, the projector projection utility captures the display screen of the personal computer at predetermined intervals.
[0030]
The captured image data is compressed into, for example, the JPEG format, and a password is added to the captured image data to be transmitted to the IP address of the projector via the wireless LAN. Since the data is transmitted to the designated IP address, there is less danger that the data will be acquired by another person even if the data is transmitted via the wireless LAN. Further, since the IP address is included in the password, the destination of the data is set only by inputting the password. Image data may be transmitted via a wired LAN.
[0031]
Upon receiving the image data, the network projector 1 proceeds to step # 21. In step # 21, the issued password is compared with the received password. In step # 22, it is determined whether or not both match. If they match, the process proceeds to step # 23, and the projection of the password projected in step # 12 is stopped.
[0032]
Then, in step # 24, the image received by the projection unit 2b is displayed on the screen 2a, and the process returns to step # 13. If the passwords do not match in step # 22, the process returns to step # 13 without displaying the image. When the "stop" button 44 is selected, the projection of the image on the screen 2a can be stopped.
[0033]
In FIG. 4 described above, when the “acquire via IrDA” button 42 is selected, a signal requesting a password is transmitted from the personal computer by IrDA. When the IrDA communication unit 23 receives the signal requesting the password, the network projector 1 shifts from the event standby state of step # 13 to step # 31.
[0034]
Then, the password is transmitted from the IrDA communication unit 23 of the network projector 1. Since communication according to the IrDA standard uses infrared light, communication cannot be performed in a room adjacent to a wall or the like, and a password cannot be obtained. Upon receiving the password, the projector projection utility of the personal computer automatically inputs the password to the password input unit and returns to step # 13. This simplifies the user operation.
[0035]
When a “password display” button (not shown) provided on the operation unit 4 is pressed, the network projector 1 shifts from the event standby state of step # 13 to step # 41. In step # 41, the password is projected on the screen 2a and is overlaid on the display image and displayed. As a result, the user who cannot recognize the password projected on the screen 2a in step # 12 can acquire the password.
[0036]
In step # 42, the process waits until a "stop" button (not shown) provided on the operation unit 4 is pressed. When the "stop" button is pressed, the process proceeds to step # 43. In step # 43, the projection of the password is stopped, and the process returns to step # 13.
[0037]
When a “shooting” button (not shown) provided on the operation unit 4 is pressed, the network projector 1 shifts from the event standby state of step # 13 to step # 51. In step # 51, the projection of the image is stopped, and the screen is projected with white light. Thus, image data of only the image of the marker described on the screen 2a can be obtained, and the screen 2a can be uniformly illuminated during shooting. Therefore, it is possible to obtain a marker writing image with less shading.
[0038]
In step # 52, the screen 2a is photographed by the document camera 3. In step # 53, the image data of the image whose projection has been stopped is fetched from the image memory 29 and is combined with the photographed image data.
[0039]
In step # 54, the combined image data is encrypted. The encryption is performed on the image data using the above-mentioned password, and the encryption can be released by the same password. In step # 55, the encrypted file is stored in the memory card 19 via the card driver 15, and the process returns to step # 13.
[0040]
When the "power OFF" button of the operation unit 4 is pressed from the event standby state in step # 13, the process proceeds to step # 61. In step # 61, the password created in step # 11 is discarded from the memory 14. Then, the power of the network projector 1 is turned off.
[0041]
The image data stored in the memory card 19 can be taken out by connecting to the user's personal computer. FIG. 5 shows a decryption screen of the document camera image decryption utility installed in the personal computer. The decryption screen 50 includes a password input unit 51, an image file generation destination folder input unit 52, and a document camera image file input unit 54.
[0042]
The password input unit 51 inputs a password included when the image data is encrypted. The image file generation destination folder input unit 52 inputs a storage destination folder of the decrypted image data. It is also possible to select and input from a list by operating the selection button 53.
[0043]
The document camera image file input unit 54 inputs a file name of an image file to be taken out from the memory card 19. By operating the selection button 55, it is also possible to select and input from a list.
[0044]
When the start button 56 is operated after inputting to the input sections (51, 52, 54), the password included in the encrypted file is compared with the input password. If they match, the decrypted image file is stored in the specified folder.
[0045]
This allows the user to handle image data captured by the document camera 3. When the network projector 1 is running, the image data in the memory card 19 connected to the network projector 1 can be extracted by a wireless LAN or a wired LAN in the same manner as described above.
[0046]
According to the present embodiment, the password created when the network projector 1 is started is transmitted to the user by optical wireless transmission means (second communication means) such as projection by visible light on the screen 2a or transmission by IrDA communication. . The image data is transmitted and received by non-optical wireless communication (first communication means) such as a wireless LAN. Therefore, image data and the like can be transmitted and received at a high speed, and a password is not intercepted from an adjacent room separated by a wall or the like. Therefore, the security of the network projector 1 can be improved without lowering usability.
[0047]
The password is generated when the network projector 1 is started and is discarded when the network projector 1 ends. Therefore, only the user who has obtained the password by the second communication unit during the activation of the network projector 1 can take out the image data stored in the memory card 19. Therefore, security can be further improved. The previous password may be discarded when the password is generated.
[0048]
Next, FIG. 6 is a block diagram showing a configuration of a digital camera which is a network device of the second embodiment and peripheral devices. The digital camera 103 is provided with a CPU 110 that performs various calculations and controls the operation of the digital camera 103. The CPU 110 includes a memory 114, a card driver 115, a switch 116, a distance measuring unit 117, a photometric unit 118, an A / D converting unit 109, a CCD driving unit 111, an aperture driving unit 112, a lens driving unit 113, an LCD 120, and a wireless LAN unit. 121 and an IrDA communication unit 123 are connected.
[0049]
The memory 114 includes a ROM and a RAM, and stores an operation program of the digital camera 103 and temporarily stores an operation. The card driver 115 causes the CPU 110 to recognize the memory card 119 and enable connection to the digital camera 103. The memory card 119 includes smart media (R) or the like, and stores image data captured by the digital camera 103.
[0050]
The switch 116 is provided on the back side of the digital camera 103, and sends a signal corresponding to a user operation to the CPU 110. The distance measurement unit 117 and the photometry unit 118 detect the distance to the subject and the amount of light. The lens driving unit 113 drives the photographing lens 105 based on the detection result of the distance measuring unit 117. The aperture driving unit 112 drives the aperture 106 based on the detection result of the photometry unit 118.
[0051]
Thus, a subject image is formed on the CCD 107 driven by the CCD driving unit 111. The A / D converter 109 is connected to the CCD 107 via the amplifier 108. The subject image received by the CCD 107 is converted into an electric signal, amplified by an amplifier 108, and A / D converted by an A / D converter 109.
[0052]
The LCD 120 is provided on a finder and a back surface of the digital camera 103, and allows a subject image captured by the CCD 107 to be visually recognized. The IrDA communication unit 123 communicates a signal of infrared communication according to the IrDA standard. The wireless LAN unit 121 performs wireless communication by making a network connection based on the wireless LAN standard.
[0053]
The peripheral device 102 of the digital camera 103 is provided with an IrDA communication unit 133 and a wireless LAN unit 132 that communicate with the IrDA communication unit 123 and the wireless LAN unit 121, respectively. Accordingly, the peripheral device 102 is connected to the digital camera 103 via a network, and the main unit 131 is driven by the instruction of the digital camera 103, and the digital camera 103 is driven by the instruction of the main unit 131. As the peripheral device 102, a strobe, an HDD, a keyboard, a printer, a digital television, and the like are wirelessly connected.
[0054]
In the digital camera 103 and the peripheral device 102 configured as described above, when the power of the digital camera 103 is turned on, the operation program of FIG. In step # 101 of the operation program, the process waits until an event occurs. When a predetermined operation is performed by a user, an event occurs and an operation corresponding to each event is performed.
[0055]
When the power of each peripheral device 102 is turned on, the operation program of FIGS. FIG. 8 shows the operation of the strobe. When the strobe is turned on, a password is generated in step # 201 and stored in a memory (not shown). The password is generated, for example, by generating a random number and combining it with the IP address assigned to the strobe. In step # 202, the process waits until an event occurs. When a predetermined operation is performed by a user, an event occurs and an operation corresponding to each event is performed.
[0056]
FIG. 9 shows the operation of the HDD. Similarly to the above, when the HDD is turned on, a password is generated in step # 301 and stored in a memory (not shown), and an event is waited in step # 302. FIG. 10 shows the operation of the keyboard. Similarly, when the power of the keyboard is turned on, a password is generated and stored in a memory (not shown) in step # 401, and an event is awaited in step # 402.
[0057]
FIG. 11 shows the operation of the printer. Similarly, when the power of the printer is turned on, a password is generated in step # 501 and stored in a memory (not shown), and an event is waited in step # 502. FIG. 12 shows the operation of the digital television. Similarly, when the power of the digital television is turned on, a password is generated and stored in a memory (not shown) in step # 601, and an event is awaited in step # 602.
[0058]
7, when the registration switch 116 is operated on the digital camera 103 side, the process proceeds to step # 111. In step # 111, a peripheral device to be registered is selected. In step # 112, the shutter is turned on toward the peripheral device to be registered. Thus, in step # 113, a password request command is transmitted from the IrDA communication unit 121 to each peripheral device in the field of view by infrared rays.
[0059]
The password request command is generated and transmitted, for example, by generating a random number and combining it with the IP address assigned to the digital camera 103. In addition, the communication range of infrared rays is limited to the photographing range in the same manner as flashlight projection, so that a password request command does not reach peripheral devices not intended by the user.
[0060]
Upon receiving the password request command, each peripheral device proceeds to steps # 203, # 303, # 403, # 503, and # 603 in FIGS. 8 to 12, respectively. In these steps, each peripheral device transmits a password to the IP address of the digital camera 103 via the wireless LAN. Since the data is transmitted to the designated IP address, there is less danger that the data will be acquired by another person even if the data is transmitted via the wireless LAN. Upon receiving the password in step # 104, the digital camera 103 stores the password in the memory 114 in step # 115 and returns to step # 101.
[0061]
When the digital camera 103 operates the switch 116 for instructing flash emission, the flow shifts from the event standby state in step # 101 to step # 121. In step # 121, a light emission signal for instructing light emission and a password are transmitted to the strobe IP address via the wireless LAN together with light emission data such as a light emission amount and a light emission pattern, and the process returns to step # 101.
[0062]
When the strobe receives the light emission signal, the process proceeds from step # 202 to step # 204 in FIG. 8, and compares the received password with the password stored in the memory. If the passwords match, the process proceeds to step # 205 to emit light based on the received light emission data, and returns to step # 202.
[0063]
When the digital camera 103 operates the switch 116 for instructing to save a file, the process shifts from the event standby state in step # 101 of FIG. 7 to step # 131. In step # 131, the image file and the password are transmitted to the IP address of the HDD via the wireless LAN, and the process returns to step # 101.
[0064]
Upon receiving the image file, the HDD proceeds from step # 302 of FIG. 9 to step # 304, and compares the received password with the password stored in the memory. If the passwords match, the process proceeds to step # 305 to save the received image file, and returns to step # 302.
[0065]
When an input is performed on the keyboard, the process proceeds from step # 402 to step # 404 in FIG. In step # 404, the input key signal and password are transmitted to the IP address of the digital camera 103 via the wireless LAN, and the process returns to step # 402.
[0066]
Upon receiving the key signal, the digital camera 103 proceeds from step # 101 to step # 141 in FIG. In step # 141, it is determined whether the state is the key reception state. In the key accepting state, it is determined whether or not the peripheral device is registered based on the keyboard IP address received in step # 142. If the keyboard is registered, the password received in step # 143 is compared with the password stored in the memory 119. If the passwords match, the flow shifts to step # 144 to perform key input processing, and returns to step # 101.
[0067]
When the digital camera 103 operates the switch 116 for instructing printing of a file, the process shifts from the event standby state of step # 101 in FIG. 7 to step # 151. In step # 151, the image file and the password are transmitted to the IP address of the printer via the wireless LAN, and the process returns to step # 101. Before transmission, the image file is converted into a printer language such as Postscript.
[0068]
Upon receiving the image file, the printer proceeds from step # 502 to step # 504 in FIG. 11, and compares the received password with the password stored in the memory. If the passwords match, the process proceeds to step # 505 to print the received image file, and returns to step # 502.
[0069]
When the switch 116 for instructing the digital camera 103 to display image data on an external display device such as a digital television is operated, the flow shifts from the event standby state in step # 101 of FIG. 7 to step # 161. In step # 161, the image displayed on the LCD 120 provided on the back of the digital camera 103 is converted into, for example, the JPEG format to form an image file. In step # 162, the image file and the password are transmitted to the IP address of the digital television via the wireless LAN, and the process returns to step # 101.
[0070]
Upon receiving the image file, the digital television proceeds from step # 602 to step # 604 of FIG. 12, and compares the received password with the password stored in the memory. If the passwords match, the process proceeds to step # 605 to display the received image file on the screen, and returns to step # 602.
[0071]
According to the present embodiment, the password is transmitted from the peripheral device 102 to the IP address of the digital camera 103 based on the password request command transmitted from the digital camera 103 by IrDA communication. For this reason, even if the password request command is transmitted from the adjacent room or the outside that is shielded by a wall or the like, the peripheral device 102 cannot receive the password request command and does not issue the password. Therefore, a person who cannot see the peripheral device 102 in the field of view cannot operate from the outside, and the security of the peripheral device 102 and the digital camera 103 can be improved.
[0072]
【The invention's effect】
According to the present invention, the second communication means for optically transmitting the password created by the network device connected to the network by the non-optical first wireless communication means such as a wireless LAN, such as visible light projection or infrared communication, Therefore, the password is not intercepted from an adjacent room or the outside across a wall or the like, and the security of the network device can be improved.
[0073]
Further, according to the present invention, the password is transmitted from the network device to the IP address of another network device based on the password request command transmitted by the optical second communication means such as infrared rays. For this reason, even if a password request command is transmitted from an adjacent room or outdoors shielded by a wall or the like, the network device cannot receive the password request command and does not issue a password. Therefore, a person who cannot see the network device within the field of view cannot operate from outside, and the security of the network device can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a network projector according to a first embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of the network projector according to the first embodiment of the present invention.
FIG. 3 is a flowchart illustrating an operation of the network projector according to the first embodiment of the present invention.
FIG. 4 is a view showing a projector projection screen of the network projector according to the first embodiment of the present invention.
FIG. 5 is a diagram showing a decryption screen of the network projector according to the first embodiment of the present invention.
FIG. 6 is a block diagram illustrating a configuration of a digital camera and peripheral devices according to a second embodiment of the present invention.
FIG. 7 is a flowchart illustrating an operation of the digital camera according to the second embodiment of the present invention.
FIG. 8 is a flowchart illustrating an operation of a strobe light according to a second embodiment of the present invention.
FIG. 9 is a flowchart showing an operation of the HDD according to the second embodiment of the present invention.
FIG. 10 is a flowchart showing the operation of the keyboard according to the second embodiment of the present invention.
FIG. 11 is a flowchart illustrating an operation of the printer according to the second embodiment of the present invention.
FIG. 12 is a flowchart illustrating an operation of the digital television according to the second embodiment of the present invention.
[Explanation of symbols]
1 Network projector
2 Projector unit
3 Document Camera
4 Operation unit
10, 21, 110 CPU
14,114 memory
19, 119 Memory card
23, 123, 133 IrDA communication unit
24 Wireless LAN card
25 Wired LAN card
102 Peripheral equipment
103 Digital Camera
121, 132 Wireless LAN unit

Claims (5)

A network device connected to the network by a first communication unit for performing information communication by non-optical wireless communication, comprising: a password creation unit for creating a password; and a second communication unit for optically wirelessly transmitting the password. A network device which authenticates a returned password and permits operation. 2. The network device according to claim 1, wherein a password is created by the password creation unit when the network device is started. The network device according to claim 1, wherein the second communication unit uses visible light. 4. The network device according to claim 1, comprising a projector. In a network device that is connected to a network by a first communication unit that performs information communication by non-optical wireless communication, a password creating unit that creates a password and a second device that receives a signal requesting transmission of the password by optical wireless communication. 2. A network device, comprising: two communication means, wherein a password returned after transmission is authenticated to permit an operation.

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