Conference system and program

Abstract

This system and program provides a conferencing environment that ensures a good communication experience even when participants in the same electronic conference are located in the same vicinity. [Solution] The conference system 700 for holding a conference over a communication network includes a main unit 300 having a first client terminal PC 100A, a first telephone 200A corresponding to the terminal, a second client terminal PC 100B, a second telephone 200B corresponding to the terminal, an optical line unit to which each client terminal is connected, and an extension terminal accommodation unit to which each telephone is connected, and a third client terminal PC 100C that is communicably connected to the optical line unit via the communication network 1000. The main unit includes a data conversion unit that converts voice transmitted from one of the two telephones into extension call voice to be transmitted to the other telephone and voice for generating voice data to be transmitted to the third client terminal via the optical line unit.

Description

TECHNICAL FIELD

[0001] The present invention relates to a conference system and a program. BACKGROUND ART

[0002] Web conference systems are known that connect a plurality of information processing terminals via a communication network to enable mutual audio and video communication. In such web conference systems, the main implementation is that video capturing the state of conference participants and utterances from the conference participants are both processed by client terminals (for example, notebook PCs (Personal Computers), desktop PCs, mobile phones, smartphones, tablet terminals, wearable PCs, etc.). Note that implementations using an external camera for video input, or using an external microphone and speaker for audio input and output are also known.

[0003] For example, Patent Document 1 discloses a system configuration in which images are displayed on a display, and audio transmission and reception are performed using a wearable microphone-speaker device. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] As described above, configurations that separate the hardware that processes video input / output and audio input / output have been conventionally known. According to such conventional techniques, when participants joining the same electronic conference are present in close proximity, in a situation where both audio transmitted via the electronic conference and audio propagating through space from the utterances of adjacent participants are audible to a single participant, there is a problem that the call environment deteriorates. For example, there is a problem that the utterance content becomes difficult to hear clearly because the directly propagated audio is heard first, and the audio via the electronic conference is heard with a slight delay.

[0005] An object of the present invention is to provide a communication control apparatus that establishes a favorable call environment even when participants in the same electronic conference are present in close proximity. MEANS FOR SOLVING THE PROBLEMS

[0006] To solve the above problems, the present invention relates to a conference system for holding conferences on a communication network, comprising: a main unit having a first client terminal, a first telephone corresponding to the first client terminal, a second client terminal, a second telephone corresponding to the second client terminal, an optical line unit to which the first and second client terminals are connected, and an extension terminal accommodation unit to which the first and second telephones are connected; and a third client terminal connected to the optical line unit via a communication network so as to be communicative. The present invention relates to a conference system for holding conferences on a communication network, wherein the main unit comprises data conversion means for converting voice transmitted from one of the first and second telephones into extension call voice transmitted to the other telephone and voice for generating voice data transmitted to the third client terminal via the optical line unit. [Effects of the Invention]

[0007] According to the present invention, a good communication environment can be established even when participants in the same electronic conference are located nearby. [Brief explanation of the drawing]

[0008] [Figure 1] An overall schematic diagram showing an example of a conference system according to an embodiment of the present invention. [Figure 2] A schematic diagram showing the flow of data transmission to participant C in a conference system according to an embodiment of the present invention. [Figure 3] A schematic diagram showing the flow of data reception from participant C in a conference system according to an embodiment of the present invention. [Figure 4] A block diagram showing an example of the hardware configuration for a PC and a conference system management server. [Figure 5] A functional block diagram showing an example of a conference system according to an embodiment of the present invention. [Figure 6]A sequence diagram showing an example of data transmission to participant C in a conference system according to an embodiment of the present invention. [Figure 7] A sequence diagram showing an example of data reception from participant C in a conference system according to an embodiment of the present invention. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the communication control device, conference system, and program according to the present invention will be described with reference to the drawings.

[0010] <Overall Overview of Conference System 700> Figure 1 is an overall schematic diagram showing an example of a conference system 700 according to an embodiment of the present invention.

[0011] In Figure 1, the location of participants A and B, who are in the vicinity of the electronic conference, is designated as nearby location P1, and the location of participant C, who is in a remote location far from nearby location P1, is designated as remote location P2. Therefore, Figure 1 illustrates a scenario in which participants A and B use the conference system 700 from nearby location P1, and participant C uses the conference system 700 from remote location P2 to participate in the same remote conference.

[0012] Participant A is participating in the meeting using PC (Personal Computer) 100A as the first client terminal, which is a video terminal, and telephone 200A as the first telephone, which is an audio terminal compatible with PC100A. Participant B is participating in the meeting using PC100B as the second client terminal, which is a video terminal, and telephone 200B as the second telephone, which is an audio terminal compatible with PC100B.

[0013] PC100A, telephone 200A, PC100B, and telephone 200B are connected to the communication network 1000 via a main unit 300, which is an embodiment of a communication control device. Telephones 200A and 200B are telephone devices also known as business phones, key telephones, or button telephones. The main unit 300 accommodates multiple public lines and controls communication between internal lines (e.g., telephones 200A, 200B) and external lines, or communication between internal lines.

[0014] Participant C is joining the meeting using PC100C as a third client terminal. PC100C is connected to communication network 1000. Furthermore, a management server 500 is connected to communication network 1000. As a result, PC100A, PC100B, PC100C, and management server 500 can communicate with each other via communication network 1000, such as the Internet.

[0015] The communication network 1000 may consist of one or more LANs (Local Area Networks) inside the firewall, or it may include the Internet outside the firewall in addition to the LANs. It may also include VPNs (Virtual Private Networks) or Wide Area Ethernet (registered trademark). The communication network 1000 may be constructed using either wired or wireless connections. Furthermore, the communication network 1000 may be a combination of wired and wireless connections. Additionally, if connected via a mobile phone network configured according to standards such as LTE (Long Term Evolution), 4G, or 5G, a LAN may not be necessary.

[0016] <Overview of data transmission and reception using the conference system 700> Figure 2 is a schematic diagram showing the data transmission flow when audio input and video input from participants A and B are communicated to participant C (PC100C) in a conference system 700 according to an embodiment of the present invention.

[0017] In Figure 2, the dashed arrows pointing from PC100A and PC100B to PC100C indicate the flow of image data. When image data is transmitted from PC100A or PC100B to PC100C, the image data is sent to IPHO300b, which is an optical line unit of the main unit 300. The image data sent to IPHO300b is combined with the audio data described later and then sent to the management server 500. The image data and audio data sent to the management server 500 are then processed, for example, by predetermined data processing in the management server 500 before being sent to PC100C. As a result, the image data transmitted from PC100A or PC100B is displayed on the display device 105 of PC100C.

[0018] In Figure 2, the solid arrow pointing from telephone 200A to PC100C indicates the flow of voice data from telephone 200A. The dotted arrow pointing from telephone 200B to PC100C indicates the flow of voice data from telephone 200B. When voice data is transmitted from telephones 200A and 200B to PC100C, the voice from telephones 200A and 200B is sent to ST300a, an extension terminal accommodating unit in the main unit 300. The main unit 300 includes a data conversion unit 351 that, when voice is transmitted from either telephone 200A or 200B, converts the voice into an extension call voice to be transmitted to the other telephone and voice to generate voice data to be transmitted to PC100C via IPHO300b. Details of the data conversion unit 351 will be described later.

[0019] That is, when transmitting audio data from telephone 200A to PC 100C, the audio from telephone 200A (solid line arrow) is divided, as shown in FIG. 2, into audio transmitted toward telephone 200B at ST300a (extension call audio) and audio sent to IPHO 300b (external line call audio). The extension call audio transmitted toward telephone 200B is an analog signal. Therefore, the audio received by telephone 200B is in the same environment as when making extension communications within the nearby site P1. Also, as will be described later, unlike the external line call audio, the extension call audio is output without passing through the management server 500, so discomfort such as hearing overlapping audio that arrives with a delay from the utterance is reduced. That is, an environment in which good voice call quality can be achieved can be formed.

[0020] On the other hand, the same applies when transmitting audio data from telephone 200B to PC 100C. That is, the audio from telephone 200B (dotted line arrow) is divided at ST300a as shown in FIG. 2 into extension call audio transmitted toward telephone 200A and external line call audio sent to IPHO 300b. Therefore, the audio received by telephone 200A is also in the same environment as when making extension communications with telephone 200B within the nearby site P1, and for the same reason as described above, discomfort such as hearing overlapping audio due to delay is reduced.

[0021] The main device 300 forms an environment in which calls between parties using audio terminals accommodated in the same ST300a, such as a plurality of participants A and B at the nearby site P1, are performed using only extension call audio as described above. In contrast, the audio from the telephone set 200A and the telephone set 200B transmitted from the ST300a to the IPHO300b is converted from analog data to digital data (A / D conversion) and synthesized at the IPHO300b. The synthesis may include not only the synthesis of the audio data of the telephone set 200A and the audio data of the telephone set 200B, but also synthesis with image data, control data, and the like transmitted from the PC100A or PC100B. In FIG. 2, the thick solid arrow directed from the IPHO300b to the management server 500 indicates the flow of a packet in which image data, audio data, and control data are synthesized.

[0022] The packet transmitted to the management server 500 is subjected to predetermined data processing (for example, packet data expansion processing) in the management server 500, and then transmitted to the PC100C. As a result, in the PC100C, the audio data transmitted from the PC100A and the PC100B is output as audio from a built-in speaker of the PC100C (or an external speaker, a headset, or the like connected to the PC100C).

[0023] FIG. 3 is a schematic diagram showing a flow when data is received from the PC100C in the conference system 700 according to the embodiment of the present invention.

[0024] In FIG. 3, the two-dot chain arrows directed from the PC100C to the PC100A and the PC100B indicate the flow of image data. When image data is transmitted from the PC100C to the PC100A and the PC100B, the image data is transmitted to the management server 500.

[0025] Furthermore, in Figure 3, the dashed arrows pointing from PC100C to PC100A and PC100B indicate the flow of audio data. When audio data is transmitted from PC100C to PC100A and PC100B, the audio data is also sent to the management server 500.

[0026] Image data (dotted arrow) and audio data (dashed arrow) transmitted from PC100C to management server 500 are sent to IPHO300b of main unit 300 after predetermined data processing (e.g., packetization) is performed on management server 500. In Figure 3, the thick solid arrows pointing from management server 500 to IPHO300b show the flow of packets in which image data, audio data, and control data from PC100C are combined. In packetization, image data corresponding to PC100A and PC100B are created, but for audio data, only one (1 channel) is used as valid audio data, and the remaining one is sent to IPHO300b as a dummy.

[0027] Then, of the image data and audio data transmitted to IPHO300b, the image data is transmitted from IPHO300b to PC100A and PC100B. As a result, the image data transmitted from PC100C is displayed on the display devices 105 of PC100A and PC100B.

[0028] On the other hand, the voice data transmitted to the IPHO300b is separated from the image data in the IPHO300b, and then the valid voice data is converted from digital data to analog data (internal call voice) (D / A conversion) and sent to the ST300a. The voice data (internal call voice) sent to the ST300a is then transmitted to telephone 200A and telephone 200B, respectively.

[0029] In this way, when audio data is transmitted from the PC 100C to the telephone set 200A and the telephone set 200B, the audio data from the PC 100C (indicated by the dashed arrow) is transmitted to the ST 300a via the IPHO 300b as shown in FIG. 3, and is converted into extension call audio. Therefore, regarding the audio received by the telephone set 200A and the telephone set 200B from the PC 100C, discomfort such as double hearing of audio due to delay is reduced.

[0030] <Hardware Configuration of PC100A, 100B, 100C, and Management Server 500> FIG. 4 is a block diagram illustrating an example of the hardware configuration of the client terminals (PC100A, 100B, 100C) and the management server 500. Here, the PC100A, 100B, and 100C are collectively referred to as "PC100" for the description. Further, since the hardware configuration of the management server 500 is equivalent to that of the PC100, components and constituent elements related to the PC100 are denoted by reference numerals in the 100s range, and components and constituent elements related to the management server 500 are denoted by reference numerals in the 500s range, which are written in parentheses below the reference numerals in the 100s range.

[0031] The PC100 (management server 500) is implemented by, for example, a computer having the illustrated configuration. The PC100 (500) includes a CPU (Central Processing Unit) 101 (501) as a control unit, a ROM (Read Only Memory) 102 (502), a RAM (Random Access Memory) 103 (503), an HDD (Hard Disk Drive) 104 (504), a display device 105 (505), an input device 106 (506), an audio input / output device 107 (507), a communication I / F (Interface) 108 (508), an external I / F 109 (509), and a bus line 110 (510).

[0032] CPU 101 (501) controls the overall operation of PC 100 (500). CPU 101 (501) reads programs and data stored in ROM 102 (502) and HDD 104 (504) from ROM 102 (502) and HDD 104 (504) into RAM 103 (503) and executes processing.

[0033] ROM102(502) is a non-volatile semiconductor memory that stores programs and data (BIOS, OS settings, network settings, etc.).

[0034] RAM103 (503) is a volatile semiconductor memory that temporarily stores programs and data.

[0035] HDD104 (504) is a non-volatile storage device that stores programs and data (OS, applications, etc.).

[0036] The display device 105 (505) consists of a display, etc., and displays various information and processing results such as a cursor, menu, window, text or images.

[0037] The input device 106 (506) consists of a keyboard, mouse, touch panel, etc., and accepts input from the user.

[0038] The audio input / output device 107 (507) consists of a microphone, speaker, headset, etc. The microphone is a type of sound collection means that inputs sound signals according to the control of the CPU 101 (501). The speaker is a type of playback means that outputs sound signals according to the control of the CPU 101 (501).

[0039] Communication I / F108(508) is an interface for data communication using communication network 1000.

[0040] External I / F109(509) is an interface for connecting to external devices. External devices include cameras and other imaging devices, recording devices, and recording media.

[0041] The recording medium 111 (511) is a flexible disk, CD, DVD, SD memory card, USB memory, etc.

[0042] Bus line 110 (510) is an address bus, data bus, etc., for electrically connecting the above components, and transmits address signals, data signals, and various control signals.

[0043] <Functional Configuration> Figure 5 is a functional block diagram showing an example of a conference system 700 according to an embodiment of the present invention.

[0044] PC100A, as the first client terminal, is the terminal used by participant A in this embodiment. PC100B, as the second client terminal, is the terminal used by participant B in this embodiment. PC100A and PC100B include a transmitting / receiving unit 151, an operation receiving unit 152, a display control unit 156, a determination unit 157, and a storage / reading unit 158. Each of these units is a function or means of functioning, realized by any of the components shown in Figure 4 operating according to instructions from the CPU 101 in accordance with a program deployed on the RAM 103.

[0045] Furthermore, PC100A and PC100B are equipped with a storage unit 159 constructed by a ROM 102 or HDD 104, etc., as shown in Figure 4.

[0046] The transmitting / receiving unit 151 is mainly implemented by the processing of the communication interface 108 by the CPU 101, and enables communication with the PC 100C and the management server 500 via the main unit 300 and the communication network 1000.

[0047] The transmitting / receiving unit 151 transmits information, etc., in response to requests from participant A (participant B) received by the operation reception unit 152 to PC100A (PC100B), and receives information transmitted from PC100A (PC100B). Thus, the transmitting / receiving unit 151 is an example of a transmission means, and the transmitting / receiving unit 151 is also an example of a reception means.

[0048] The operation reception unit 152 is mainly implemented by the processing of the input device 106 by the CPU 101, and receives input from participant A (participant B) to the input device 106.

[0049] The display control unit 156 is mainly implemented by the processing performed by the CPU 101 on the display device 105, and causes the display device 105 to display various display screens.

[0050] The decision unit 157 is mainly implemented by the CPU 101 and performs various decisions.

[0051] The memory and read unit 158 ​​is mainly implemented by the CPU 101 and performs operations to store various data in the memory unit 159 and to read various data from the memory unit 159.

[0052] Telephone 200A, designated as the first telephone, is a telephone compatible with PC100A, and in this embodiment, it is a telephone used by participant A in conjunction with PC100A. Telephone 200B, designated as the second telephone, is a telephone compatible with PC100B, and in this embodiment, it is a telephone used by participant B in conjunction with PC100B.

[0053] Telephones 200A and 200B mainly consist of a transmitter 251 and a receiver 252. The transmitter 251 is, for example, the handset of telephone 200A (telephone 200B), which captures the voice of participant A (participant B) and transmits the captured sound to the main unit 300. The receiver 252 is, for example, the handset of telephone 200A (telephone 200B), which receives the voice of participant C via the main unit 300, etc. In other words, in PC100A and PC100B, during a conference, the voice input and voice output from the voice input / output unit 153 are muted, and telephones 200A and 200B function as the voice input / output unit 153.

[0054] The main unit 300 includes a data conversion unit 351 as a data conversion means. The data conversion unit 351 has the function of generating two audio data from internal call audio from one telephone (telephone 200A), for example. One of the two audio data is internal call audio transmitted to the other telephone (telephone 200B). The other is audio data relating to external call audio transmitted from ST300a to PC100C via IPHO300b.

[0055] Furthermore, the data conversion unit 351 has a function to combine the voice data from telephone 200A and the voice data from telephone 200B when transmitting voice data from telephone 200A and telephone 200B to PC 100C.

[0056] Furthermore, the data conversion unit 351 has a function to separate the audio data from the packets received from PC100C when transmitting audio data from PC100C to PC100A and PC100B.

[0057] In this embodiment, PC100C, acting as the third client terminal, is the terminal used by participant C. PC100C can communicate with the main unit 300 (PC100A and PC100B) and the management server 500 via the communication network 1000. In PC100C, the audio input / output unit 153 is used for audio input and output during the conference. Note that the other functional configurations are the same as those of PC100A and PC100B, so their explanation is omitted.

[0058] The management server 500 can communicate with the main unit 300 (PC100A and PC100C) and PC100C via the communication network 1000. The management server 500 performs tasks such as processing packets (control data, image data, and audio data) received from the main unit 300, and processing image data and audio data received from PC100C.

[0059] <Sequence> Figure 6 is a sequence diagram showing an example of data transmission to participant C in the conference system 700 according to an embodiment of the present invention, and Figure 7 is a sequence diagram showing an example of data reception from participant C in the conference system 700 according to an embodiment of the present invention.

[0060] Figure 6 illustrates a case where participant A transmits images and audio to participants B and C. In this case, participant A transmits images from PC 100A (S601) and audio from the transmitter unit 251 of telephone 200A (S602).

[0061] The audio transmitted in step S602 is an internal call audio in analog data format, and this audio is input to ST300a of the main unit 300. The audio input to ST300a is then converted by the data conversion unit 351 of the main unit 300 into an internal call audio to be transmitted to telephone 200B and an audio to be input to IPHO300b.

[0062] Then, the earpiece 252 of telephone 200B receives the internal call audio transmitted from ST300a (S603). Meanwhile, the audio input to IPHO300b is converted to digital format by A / D conversion in IPHO300b. Subsequently, the digitized audio data is combined with the image data transmitted in step S601 by, for example, data conversion processing in the data conversion unit 351 (S604). In step S604, if participant B also transmits a call (voice transmission) from telephone 200B, the audio data corresponding to that call is also included and combined as one channel of data. For example, the combined data is a packet consisting of control data, image data and audio data, etc., and IPHO300b transmits the packet to the management server 500.

[0063] The management server 500 processes the packets received from IPHO300b (S605), and transmits image data and audio data from PC100A to PC100C, and image data from PC100A to PC100B.

[0064] As described above, data transmission occurs in this manner, resulting in no change to the web conferencing environment for participant C, while participant B can receive audio from participant A via internal call audio without going through the management server 500. Therefore, the audio received by telephone 200B is in the same environment as when making an internal call with telephone 200A within the nearby P1 location, reducing the discomfort caused by delays such as hearing double audio.

[0065] Figure 7 shows a case where data flows in the opposite direction to Figure 6, illustrating a scenario where participant C transmits images and audio to participants A and B. In this case, participant C transmits images and audio from PC100C (S701). The image data and audio data from PC100C are then transmitted to the management server 500.

[0066] The management server 500 processes the image data and audio data received from PC100C (S702) and transmits the image data and audio data from PC100C to IPHO300b of main unit 300. The data transmitted from management server 500 is a packet containing not only the image data and audio data from PC100C but also control data, etc., and management server 500 transmits the packet to IPHO300b.

[0067] The packets received by IPHO300b are separated into image data and audio data by data conversion processing in the data conversion unit 351 (S703), and the image data is transmitted from IPHO300b to PC100A and PC100B respectively as digital data. Once PC100A and PC100B each receive the image data from IPHO300b (S704), participants A and B can view the images shared by participant C on the display devices 105 of their respective PCs.

[0068] In step S703, the separated audio data is converted to analog by D / A conversion in IPHO300b. The analogized audio data is transmitted from IPHO300b to telephones 200A and 200B via ST300a, and telephones 200A and 200B receive the audio from PC100C (S705).

[0069] As described above, data transmission occurs in this manner, resulting in no change to the web conference environment for participant C, while participants A and B can receive audio from participant C via internal phone call. Therefore, the only sound reaching participant A (or participant B) is the audio received by telephone 200A (or telephone 200B), resulting in a good call environment.

[0070] The sequence of processes shown in the sequence diagrams of Figures 6 and 7 can be constructed as a program. This program may be distributed as an installable or executable file, recorded on a computer-readable storage medium. Examples of storage media include CD-R (Compact Disc Recordable), DVD (Digital Versatile Disk), Blu-ray® Disc, SD card, or USB memory. Furthermore, the storage medium can be provided domestically or internationally as a program product.

[0071] The present invention is not limited to the embodiments described above, and can be modified in any way that a person skilled in the art can conceive of, including other embodiments, additions, changes, and deletions. Furthermore, any embodiment that achieves the function and effects of the present invention is included within the scope of the present invention.

[0072] [Aspect 1] Embodiment 1 is a conference system for holding a conference on a communication network, comprising a main unit having a first client terminal, a first telephone corresponding to the first client terminal, a second client terminal, a second telephone corresponding to the second client terminal, an optical line unit to which the first and second client terminals are connected, and an extension terminal accommodation unit to which the first and second telephones are connected, and a third client terminal that is communicably connected to the optical line unit via a communication network, wherein the main unit is equipped with data conversion means that converts voice transmitted from one of the first and second telephones into extension call voice transmitted to the other telephone and voice for generating voice data transmitted to the third client terminal via the optical line unit.

[0073] [Aspect 2] Embodiment 2 is characterized in that, in Embodiment 1, when the data conversion means receives voice data from the third client terminal, it converts the voice data into an extension call voice.

[0074] [Aspect 3] Embodiment 3 is a program to be executed by a main unit comprising an extension terminal accommodation unit capable of connecting multiple telephones and an optical line unit that enables connection to a communication network, characterized in that, when voice is sent and received between two or more telephones connected to the same extension terminal accommodation unit and one or more client terminals that are communicably connected to the optical line unit via the communication network, when the voice is transmitted from one of the two or more telephones, the program causes the computer to execute a data conversion process that converts the voice into extension call voice to be transmitted to the other telephones and voice for generating voice data to be transmitted to the client terminals via the optical line unit. [Explanation of Symbols]

[0075] 100A: PC 100B: PC 100C: PC 200A: Telephone 200B: Telephone 300: Main device 300a :ST 300b :IPHO 351: Data conversion unit 500: Management Server 700: Conference System 1000: Communication Network [Prior art documents] [Patent Documents]

[0076] [Patent Document 1] Japanese Patent Publication No. 2019-021248

Claims

1. The first client terminal and A first telephone corresponding to the aforementioned first client terminal, The second client terminal and A second telephone corresponding to the aforementioned second client terminal, A main unit having an optical line unit to which the first client terminal and the second client terminal are connected, and an extension terminal accommodation unit to which the first telephone and the second telephone are connected, A third client terminal that is connected to the optical line unit via a communication network in a way that allows communication, Includes, A conferencing system for holding conferences on the aforementioned communication network, The main device is The system includes data conversion means that converts voice transmitted from one of the first and second telephones into internal call voice transmitted to the other telephone and voice for generating voice data transmitted to the third client terminal via the optical line unit. A conference system characterized by the following features.

2. When the data conversion means receives voice data from the third client terminal, it converts the voice data into internal call voice. The conference system according to feature 1.

3. A program to be executed by a main unit comprising an extension terminal accommodating unit capable of connecting multiple telephones and an optical line unit that enables connection to a communication network, When transmitting and receiving voice between two or more telephones connected to the same extension terminal housing unit and one or more client terminals that are communicably connected to the optical line unit via the communication network, when the voice is transmitted from one of the two or more telephones, On the computer, The system performs a data conversion process to convert the aforementioned audio into internal call audio to be transmitted to another telephone and audio for generating audio data to be transmitted to the client terminal via the optical fiber unit. A program characterized by the following features.

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