Patent Publication Number: US-2002008779-A1

Title: Audio/video system and function-extending module therefor

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to an audio/video (A/V) system, and more particularly, to an A/V system capable of reproducing various source A/V data and function-extending modules installed in the A/V system, which are capable of and extending the functions of the A/V system.  
       [0003] 2. Description of the Related Art  
       [0004] Digital ground wave broadcasting which complies with the Advanced Television Systems Committee (ATSC) standards has begun. Consumer electronics product manufacturers are disclosing various digital media products, including digital televisions capable of receiving digital broadcasts and digital versatile disc (DVD) players and a digital camcorders capable of recording and reproducing digital broadcasts.  
       [0005] As various digital media apparatuses particularly related to the digital TV market are being disclosed, potential consumers are being confused. New specifications are being developed at such a fast rate that digital TVs are becoming more complicated and new products are quickly becoming obsolete.  
       [0006] New digital media products such as digital broadcast receiving apparatuses, satellite broadcast receiving apparatuses, DVD players, hard disc drives, and an Internet access apparatuses, increase the number of manipulation methods a user has to learn and the number of remote controllers. In addition, a user has to pay a lot of money to buy digital media products. Also, the digital media products take up a large amount of space in a house and each digital media product needs a power line for operation. For operating a product that reproduces scenes displayed on a digital TV, such as a DVD player, the product should be connected to a digital TV using an electric cable.  
       [0007] Meanwhile, the appearance of digital media products has made it possible to have a home network connecting multiple home appliances in a house. If the home network is implemented, a user can control multiple appliances in the house with only one apparatus. In addition, the user can control the appliances in the house through the Internet even when the user is in a remote place.  
       SUMMARY OF THE INVENTION  
       [0008] It is a first object of the present invention to provide an A/V system capable of implementing a plurality of digital media apparatuses in one system and function-extending modules therefor.  
       [0009] It is a second object of the present invention to provide an A/V system having specifications which a consumer can select and function-extending modules therefor.  
       [0010] It is a third object of the present invention to provide an A/V system which can be upgraded and function-extending modules therefor.  
       [0011] To accomplish the first object of the present invention, there is provided an audio/video (A/V) system having one or more function-extending modules, each function-extending module capable of sending and receiving A/V data and storing control information for the function-extending module; a module rack into which the function-extending modules are detachably inserted; and a base module for receiving the control information from the function-extending modules mounted in the module rack, displaying the control information, and, if a user input according to the displayed control information is received, sending the user input to a corresponding function-extending module and reproducing source A/V data provided by the function-extending module in response to the sent user input.  
       [0012] It is preferable that each function-extending module stores an index page as control information and the base module has a browser for displaying a main page in which selection information for the function-extending modules is displayed, requesting an index page to a function-extending module selected through the main page, displaying the requested index page, and sending a user input, which is input through the index page, to the selected function-extending module.  
       [0013] It is preferable that the selection information is provided from the function-extending modules and display in the main page.  
       [0014] It is preferable that the function-extending module has a communications interface unit for communicating with the base module; a memory unit for storing an Internet protocol (IP) address and the index page; a signal processing unit for processing source A/V data; and a control unit for providing the IP address and index page to the base module, and controlling the function-extending module so that source A/V data, which is processed by the signal processing unit in response to a user input received by the base module, is sent to the base module through the communications interface unit.  
       [0015] It is preferable that the communications interface unit is an IEEE1394 interface unit, and the signal processing unit has a transport stream processing unit for converting the A/V data into an MPEG transport stream and outputting the MPEG transport stream to the IEEE1394 interface unit.  
       [0016] It is preferable that the base module has a memory unit storing the browser; a control unit for receiving the IP address from the function-extending module inserted into the module rack and activating the browser; a user input unit for receiving a user input to the browser; a signal processing unit for dividing the source ANV data received through the communications interface unit into audio data and video data and processing respective data; an audio output unit for outputting audio data processed by the signal processing unit; and a video output unit for outputting video data processed by the signal processing unit.  
       [0017] It is preferable that the function-extending module is one of a digital broadcast receiving module, a digital satellite broadcast receiving module, a cable broadcast receiving module, a digital versatile video (DVD) module, a digital video cassette recorder (DVCR) module, a game module, an Internet access module, a hard disc drive module, and a combination of at least two among these modules. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0018] The above object and advantages of the present invention will become more apparent by describing in detail a preferred embodiment thereof with reference to the attached drawings in which:  
     [0019]FIGS. 1A through 1D are views showing the external appearance of a modular television as a preferred embodiment of an audio/video (A/V) system according to the present invention;  
     [0020]FIGS. 2 and 3 are diagrams for explaining structures for connecting a base module and function-extending modules through a module rack;  
     [0021]FIGS. 4A and 4B are block diagrams of a modular television as a preferred embodiment of an A/V system according to the present invention;  
     [0022]FIGS. 5A and 5B are block diagrams of a broadcast receiving module as a preferred embodiment of a function-extending module according to the present invention;  
     [0023]FIGS. 6A and 6B are block diagrams of a digital satellite broadcast receiving module as a preferred embodiment of a function-extending module according to the present invention;  
     [0024]FIG. 7 is a block diagram of a hard disc drive module as a preferred embodiment of a function-extending module according to the present invention;  
     [0025]FIG. 8 is a block diagram of a digital versatile disc (DVD) module as a preferred embodiment of a function-extending module according to the present invention;  
     [0026]FIG. 9 is a block diagram of an Internet access module as a preferred embodiment of a function-extending module according to the present invention;  
     [0027]FIG. 10 is a block diagram of a game module as a preferred embodiment of a function-extending module according to the present invention;  
     [0028]FIG. 11 is a block diagram of a digital video cassette recorder (DVCR) as a preferred embodiment of a function-extending module according to the present invention;  
     [0029]FIG. 12 is a hierarchical structure adopting a base module and function-extending modules according to a preferred embodiment of the present invention for communications based on a client-server model;  
     [0030]FIG. 13 is a flowchart of a control process for a modular television system as a preferred embodiment of an A/V system according to the present invention; and  
     [0031]FIG. 14 is a diagram of an example of a main page. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0032]FIGS. 1A and 1B are views showing the external appearance of a modular television system which is a preferred embodiment of an A/V system according to the present invention. FIGS. 1C and 1D are views showing the external appearance of modular television systems as another preferred embodiments of an AN system according to the present invention. FIG. 1A is a front view of the A/V system with a module rack&#39;s door closed. FIG. 1B is a front view of the A/V system with the module rack&#39;s door open. FIGS. 1C and 1D are perspective views.  
     [0033] Referring to FIGS. 1A through 1D, a modular TV system has a display device  18  supported by a TV stand  10 . The display device  18  may be a cathode-ray tube (CRT), a ferroelectric LCD (FLCD), a field emission display (FED), or a plasma display panel (PDP). A module rack  16  is installed at the center of the TV stand  10  under the display device  18 , and speakers  12  are installed to the right and left of the module rack  16 .  
     [0034] Referring to FIGS. 1A and 1B, a door which is opened and closed by sliding or rotating is attached to the module rack  16 . A plurality of module-inserting holes are formed in the front of the module rack  16  which is exposed to the outside when the door  14  is open. A digital video cassette recorder (DVCR) module is inserted into the uppermost module-inserting hole the front surface of the module rack  16 . Reference number  17  indicates a hole for inserting a digital video tape. The DVCR module is a kind of function-extending module, which will be explained later.  
     [0035] Referring to FIG. 1C, module-inserting holes may be formed in a horizontal line so that a plurality of function-extending modules can be inserted in a row.  
     [0036] Function-extending modules are for extending the functions of the modular TV system. For example, if a user buys a DVD module and installs the DVD module in the module rack  16 , the modular TV system will have a DVD player function.  
     [0037] A base module (not shown) is installed at the back of the module rack  16 . The base module communicates control commands with the function-extending modules in a client-server fashion. That is, the base module receives control information from the function-extending modules inserted into the module rack  16 , and outputs and displays the received control information on the display device  18 . If a user input corresponding to the displayed control information is received, the base module sends the user input to one of the function-extending modules. The function-extending module sends A/V data corresponding to the received user input to the base module. The base module processes the received A/V data and then outputs the A/V data to the display device  18  and/or the speakers  12 .  
     [0038] For example, the function-extending module stores an index page containing control information for controlling itself and the base module has a browser for selecting a function-extending module. The browser displays a main page, in which selection information for at least one or more function-extending modules is contained, for the user. The browser requests an index page from a function-extending module selected by the user through the main page, and displays the index page to the user. If the user inputs a control command through the displayed index page, the browser sends the control command again to the function-extending module.  
     [0039]FIGS. 2 and 3 are diagrams for explaining structures for connecting a base module and function-extending modules through a module rack  16 .  
     [0040] Referring to FIG. 2, the base module  100  has a plurality of connectors  110  for module connection. Each connector  110  contains two communications ports  112  and  114  and one power connection port  116 . The two communications ports  112  and  114  and the power connection port  116  are designed so that each function-extending module can be easily inserted and connected into a module-inserting hole (not shown) of the module rack  16 .  
     [0041] Referring to FIG. 3, a function-extending module  200  also has two communications ports  292  and  294  and one power connection port  296 . Since the function-extending module  200  is in a casing, the communications ports  292  and  294  and power connection port  296  are formed so as to protrude from the casing. Therefore, if the function-extending module  200  is inserted into a module-inserting hole formed in the module rack  16 , the corresponding ports contact each other and the base module  100  and the function-extending module  200  are electrically connected. Also, if a plurality of function-extending modules  200  are inserted into the module rack  16 , the plurality of function-extending modules are connected to the base module  100  in a daisy-chain fashion. The method for connecting the base module  100  to the plurality of function-extending modules  200  may be determined in various ways as needed. Here, communications ports  112  and  114  of the base module  100  and communications ports  292  and  294  of the function-extending module are electrically connected to their own communications interface units  101  and  201 , respectively. Each of the communications interface units  101  and  201  may be implemented as an IEEE1394 interface unit complying with the IEEE1394 protocol. The communications interface units  101  and  201  can be connected through a universe serial bus (USB), a peripheral interconnect (PCI) bus, or a Fast-Ethernet. Also, other communications protocols that support appropriate transmission speed with respect to A/V data to be transmitted can be adopted.  
     [0042]FIGS. 4A and 4B are block diagrams of a modular television system which is a preferred embodiment of an A/V system according to the present invention. Referring to FIG. 4A, a base module  100  has a communications interface unit  101 , a signal processing unit  110 , a video processing unit  104 , an audio processing unit  105 , a user input unit  106 , a memory unit  107 , and a control unit  108 .  
     [0043] The memory unit  107  includes a RAM, ROM, and a flash memory depending on the embodiment of the present invention. The RAM is used as a buffer for processing image data which forms a main page to be explained later, the ROM stores a browser for searching for a function-extending module  200 , and the flash memory stores the Internet protocol (IP) address of the function-extending module  200 .  
     [0044] The user input unit  106  receives user inputs, which are input through a command key (not shown) or a remote controller, and sends the user inputs to the control unit  108 . The communications interface unit  101  communicates data with the outside. In the signal processing unit  110 , the A/V data, which is received through the communications interface unit  101 , is divided into video data and audio data, processed, and then the video data and audio data are output to the video processing unit  104  and the audio processing unit  105 , respectively. The video processing unit  104  processes the video data output from the signal processing unit  110  and sends the video data to the display device  18 , and the audio processing unit processes the audio data output from the signal processing unit  110  and sends the audio data to the speakers  12 .  
     [0045] Referring to FIG. 4B, if the A/V data received by the base module  100  is an MPEG transport stream, the signal processing unit  110  has a transport stream processing unit  102  for demultiplexing the MPEG transport stream. If the communications interface unit  101  is implemented as an IEEE1394 interface unit  101   b , the communications interface unit  101  sends and receives an MPEG transport stream, a state signal, or a control signal, which are sent according to the IEEE1394 protocol, and sends the MPEG transport stream to the transport stream processing unit  102  and the state signal and control signal to the control unit  108 .  
     [0046] The mixing unit  103  makes an image or text information signal, which is input from the outside (a), or from the control unit  108 ( b ), overlap with a video signal (c), and outputs the overlapped signal to the video processing unit  104 . By doing so, data, including caption data, can be displayed.  
     [0047] Referring to FIG. 4A, the function-extending module  200  has a communications interface unit  201 , a signal processing unit  203 , a memory unit  204 , and a control unit  205 .  
     [0048] The communications interface unit  201  communicates with the base module  100 . The memory unit  204  stores an IP address assigned to the function-extending module  200 , an index page, and a function-performing program needed to perform a function given to the function-extending module  200 , and, when necessary, source ANV data. The signal processing unit  203  signal processes source A/V data and outputs the processed A/V data to the communications interface unit  201 . The control unit  205  provides the IP address and index page to the base module  100 , and responds to a user input, which is received by the base module  100 , so that corresponding the processed A/V data can be sent to the base module  100 . Also, when necessary, the control unit  205  sends an install program, which the base module  100  requires to control the function-extending module  200 , to the base module  100 .  
     [0049] The source A/V data is data that is requested by the user, and is provided to the function-extending module  200  from the outside or is stored in the memory unit  204  of the function-extending module  200 . The type of source A/V data depends on the function of the function-extending module  200 . If the function-extending module  200  is a DVD module for performing a DVD player function, the source A/V data is AN data recorded on the DVD. If the function-extending module  200  is a hard disk drive (HDD) module, the source A/V data is predetermined data recorded on a hard disk.  
     [0050] The signal processing unit  203  processes signals appropriately depending on the characteristics of the source A/V data. For example, if the function-extending module  200  is a cable broadcast receiving module for receiving a cable broadcast signal, the signal processing unit  203  demodulates and decodes a cable broadcast signal received through a tuner. If the function-extending module  200  is a DVD module, the signal processing unit  203  decodes data read from a DVD and provides the decoded data to the communications interface unit  201 , or encodes data provided by other function-extending modules and records the encoded data on the DVD.  
     [0051] The memory unit  204  has a RAM, a ROM, and a flash memory as the base module  100 . The RAM may be used as a buffer. The ROM stores an application program so that the function-extending module  200  can operate as a server for the browser in the base module  100 . In particular, the ROM stores an index page which is needed by the function-extending module  200  operating as a server to the base module  100 . The flash memory stores an IP address assigned to the function-extending module  200 .  
     [0052] The control unit  205  operates the server stored in the ROM so that the function-extending module  200  communicates with the base module  100  in a client-server fashion.  
     [0053] Referring to FIG. 4B, if the function-extending module  200  communicates an MPEG transport stream with the base module  100 , the signal processing unit  203  has a transport stream processing unit  202  which multiplexes or demultiplexes the MPEG transport stream. If the communications interface unit  201  is implemented as an IEEE1394 interface unit  201   b , the communications interface unit  201  sends and receives an MPEG transport stream, a state signal, or a control signal, which are sent according to the IEEE1394 protocol.  
     [0054]FIGS. 5A and 5B are block diagrams of a broadcast receiving module which is a preferred embodiment of a function-extending module according to the present invention. Referring to FIG. 5A, the broadcast receiving module  210  has a receiving terminal  211  for receiving a digital broadcast signal, a receiving terminal  212  for receiving a cable broadcast signal, a switching unit  213  for selecting one of the receiving terminals  211  and  212 , a tuner  214 , a signal processing unit  210   a , a communications interface unit  218 , a memory unit  219   a , and a control unit  219 . The broadcast receiving module  210  also has communications ports  292 - 1  and  294 - 1  and a power connection port  296 - 1 , which protrude from from the casing of the broadcast receiving module  210 .  
     [0055] The receiving terminals  211  and  212  receive a digital broadcast signal and a cable broadcast signal transmitted from the outside. The switching unit  213  selects one of the receiving terminals  211  and  212 . The tuner  214  selects one of the digital broadcast signal and cable broadcast signal received through the receiving terminals  211  and  212 , respectively. The signal processing unit  210   a  processes the signal selected by the tuner  214  and outputs the signal to the communications interface unit  218 . The communications interface unit  218  communicates with the base module  100 . The memory unit  219   a  stores the assigned IP address and an index page. The control unit  219  provides the IP address and index page to the base module  100 , and controls the communications interface unit  218  so that the transport stream, which is output from the signal processing unit  210   a  in response to a user input received by the base module  100 , is sent to the base module  100  through the communications interface unit  218 .  
     [0056] For example, referring to FIG. 5B, the signal processing unit  210   a  has a channel decoder  215  for channel decoding, a card connection unit  216 , and a transport stream processing unit  217  for demultiplexing a transport stream. The communications interface unit  218  may be implemented as an IEEE1394 interface unit complying with the IEEE1394 protocol. The card connection unit  216  may be implemented as a point of deployment (POD) connection unit, into which a POD card for authenticating a user identification is inserted. The POD connection unit reads a user identification number from a POD card inserted by a user, and if the user is authenticated, it electrically connects the channel decoder  215  and the transport stream processing unit  217  so that the broadcast receiving module  210  can operate. Meanwhile, a digital broadcast module or a cable broadcast module may be separately implemented by making a digital broadcast receiving module with only a receiving terminal  211  for receiving a digital broadcast signal and without a switching unit  213 , or by making a cable broadcast receiving module with only a receiving terminal  212  for receiving a cable broadcast signal and without a switching unit  213 .  
     [0057]FIGS. 6A and 6B are block diagrams of a digital satellite broadcast receiving module which is a preferred embodiment of a function-extending module according to the present invention. The digital satellite broadcast receiving module  220  has a satellite broadcast receiving unit  221 , a signal processing unit  220   a , a communications interface unit  224 , a memory unit  226 , and a control unit  225 . The digital satellite broadcast receiving module  220  also has communications ports  292 - 2  and  294 - 2  and a power connection port  296 - 2 , which protrude from the casing of the digital satellite broadcast receiving module  220 .  
     [0058] The digital satellite broadcast receiving unit  221  receives a digital satellite broadcast signal. The signal processing unit  220   a  processes the received digital satellite broadcast signal. The communications interface unit  224  communicates with the base module  100 . The memory unit  226  stores an IP address and an index page. The control unit  225  provides the IP address and index page to the base module  100 , and controls communications interface unit  224  so that a digital satellite broadcast signal, which corresponds to a user input received by the base module  100 , is sent to the base module  100  through the communications interface unit  224 .  
     [0059] For example, referring to FIG. 6B, the signal processing unit  220   a  has a card connection unit  222  and a transport stream processing unit  223 . Also, the communications interface unit  224  may be implemented as an IEEE1394 interface unit complying with the IEEE1394 protocol. The card connection unit  222  can be implemented as the POD connection unit, which was explained referring to FIG. 5B.  
     [0060]FIG. 7 is a block diagram of a hard disc drive module which is a preferred embodiment of a function-extending module according to the present invention. The hard disc drive module  230  has a hard disc drive  231 , a communications interface unit  233 , a memory unit  235 , and a control unit  234 . The hard disc drive module  230  also has communications ports  292 - 3  and  294 - 3  and a power connection port  296 - 3 , which protrude from the casing of the hard disc drive module  230 .  
     [0061] The memory unit  235  stores an IP address and an index page. In the index page, a GUI-type user interface for controlling the hard disc drive module  230  is displayed. The communications interface unit  233  communicates with the base module  100 . The control unit  234  provides the IP address assigned to the hard disc drive module  230  and the index page to the base module  100 , and controls the hard disc drive module  230  so that data recorded on the hard disc  231  is sent to the base module  100  through the communications interface unit  233  in response to a user input received by the base module  100 . Also, the communications interface unit  233  may be implemented as an IEEE1394 interface unit complying with the IEEE1394 protocol.  
     [0062]FIG. 8 is a block diagram of a digital versatile disc (DVD) module which is a preferred embodiment of a function-extending module according to the present invention. The DVD module  240  has a deck unit  241 , a signal processing unit  243 , a communications interface unit  244 , a memory unit  246 , and a control unit  245 . Also, the DVD module has communications ports  292 - 4  and  294 - 4  and a power connection port  296 - 4 , which protrude from the stand casing of the DVD module  240 .  
     [0063] A DVD is mounted on the deck unit  241  so that source A/V data can be read or recorded. The signal processing unit  243  reads source A/V data from the DVD mounted on the deck unit  241  and processes the data so as to reproduce it, or processes A/V data input from the outside so as to record it as source A/V data. The communications interface unit  244  communicates with the base module  100 . The memory unit  246  stores an IP address and an index page. In the index page, a GUI-type user interface for controlling the DVD module  240  is displayed. The control unit  245  provides the IP address and index page to the base module  100 , and controls the deck unit  241 , the signal processing unit  243  and the communications interface unit  244  so that source A/V data, which is read from the DVD in response to a user input received by the base module  100  and processed by the signal processing unit  243 , is sent to the base module  100  through the communications interface unit  244 .  
     [0064]FIG. 9 is a block diagram of an Internet access module which is a preferred embodiment of a function-extending module according to the present invention. The Internet access module  250  has an Internet access unit  251 , a communications interface unit  254 , a memory unit  256 , and a control unit  255 . Also, the Internet access module  250  has communications ports  292 - 5  and  294 - 5  and a power connection port  296 - 5 , which protrude from the casing of the Internet access module  250 .  
     [0065] The Internet access unit  251  accesses the Internet for communications. The communications interface unit  254  communicates with the base module  100 . The memory unit  256  stores an IP address and an index page. In the index page, a GUI-type user interface for controlling the Internet access module  250  is displayed. The control unit  255  provides the IP address and index page to the base module  100 , and controls the Internet access unit  251  and the communications interface unit  254  so that a web page received through the Internet access unit  251 , in response to a user input received by the base module  100 , is sent to the base module  100  through the communications interface  254 . Also, the communications interface unit  254  may be implemented as an IEEE1394 interface unit complying with the IEEE1394 protocol. In addition, a USB bus or a PCI bus can be connected, or other communications protocols that support appropriate transmission speed with respect to A/V data to be transmitted, such as a Fast-Ethernet, can be adopted.  
     [0066]FIG. 10 is a block diagram of a game module which is a preferred embodiment of a function-extending module according to the present invention. The game module  260  has a game cartridge installing unit  262 , a game cartridge control unit  263 , a communications interface unit  264 , a memory unit  266 , and a control unit  265 . Also, the game module has communications ports  292 - 6  and  2946 , and a power connection port  296 - 6 , which protrude from the casing of the game module  260 .  
     [0067] In the game cartridge installing unit  262 , a game cartridge is inserted. The game cartridge control unit  263  controls the game cartridge installing unit  262 . The communications interface unit  264  communicates with the base module  100 . The memory unit  266  stores an IP address and an index page. In the index page, a GUI-type user interface for controlling the game module  260  is displayed. The control unit  265  provides the IP address and index page to the base module  100 , and controls the game module  260  so that game contents stored in a game cartridge (not shown) are sent to the base module  100  through the communications interface unit  264 . Also, the communications interface unit  264  may be implemented as an IEEE1394 interface unit complying with the IEEE1394 protocol. In addition, a USB bus or a PCI bus can be connected, or other communications protocols that support appropriate transmission speed with respect to A/V data to be transmitted, such as a Fast-Ethernet, can be adopted.  
     [0068]FIG. 11 is a block diagram of a digital video cassette recorder (DVCR) which is a preferred embodiment of a function-extending module according to the present invention. The DVCR module  270  has a deck unit  271 , a signal processing unit  273 , a communications interface unit  274 , a memory unit  276 , and a control unit  275 . Also, the DVCR module  270  has communications ports  292 - 7  and  294 - 7  and a power connection port  296 - 7 , which protrude from the casing of the DVCR module  270 .  
     [0069] On the deck unit  271 , a DVCR is mounted so that source A/V data can be read. The signal processing unit  273  reads source A/V data from the DVCR mounted on the deck unit  271  and processes the data. The communications interface unit  274  communicates with the base module  100 . The memory unit  276  stores an IP address and an index page. In the index page, a GUI-type user interface for controlling the DVCR module  270  is displayed. The control unit  275  provides the IP address and index page to the base module  100 , and controls the deck unit  271 , the signal processing unit  273 , and the communications interface unit  274  so that source A/V data, which is read from the DVCR in response to a user input received by the base module  100  and processed by the signal processing unit  273 , is sent to the base module  100  through the communications interface unit  274 . Also, the communications interface unit  274  may be implemented as an IEEE1394 interface unit complying with the IEEE1394 protocol. In addition, a USB bus or a PCI bus can be connected, or other communications protocols that support appropriate transmission speed with respect to A/V data to be transmitted, such as a Fast-Ethernet, can be adopted.  
     [0070]FIG. 12 is a hierarchical structure adopting a base module and function-extending modules according to a preferred embodiment of the present invention for communications based on a client-server model. Referring to FIG. 12, data communications between the base module  100  and a function-extending module complies with the IEEE1394 protocol.  
     [0071]FIG. 13 is a flowchart of a control process for a modular television system which is a preferred embodiment of an A/V system according to the present invention. Referring to FIG. 13, if a modular TV system is turned on in step  1302 , the base module  100 , which is a client, determines whether or not the function-extending module  200  is inserted into the module rack  16  in step  1304 .  
     [0072] The inserted function-extending module  200  sends an index page to the base module  100 , and the base module  100  installs the received index page in step  1306 . At this time, the function-extending module  100  also sends an IP address and the base module  100  stores the received IP address. However, the step for sending and receiving the IP address may be performed independently from step  1306 .  
     [0073] If the user starts the operation of the base module  100 , the browser in the base module  100  begins to operate in step  1308 , and displays a main page, as shown in FIG. 14, in step  1310 . In the main page, icons indicating various function-extending modules as described above are displayed. An icon may be sent by a function-extending module after it has been requested, or may be stored in the base module  100  and then displayed in the main page. If a main page is formed so that an icon is sent by each corresponding function-extending module after it has been requested, the manufacturer of the function-extending modules may load various icons on the function-extending modules so that icons displayed in the main page can change in various ways.  
     [0074] If the user selects a predetermined icon display in the main page in step  1312 , the browser stored in the base module  100  calls the index page of a function-extending module  200  corresponding to the selected icon and displays the index page in step  1314 . At this time, step  1306  can be omitted and the index page can be called directly from the corresponding function-extending module  200  in step  1314 .  
     [0075] Since a GUI-type user interface is displayed in the displayed index page, if an icon for performing a predetermined function is selected in step  1316 , the selected control command (user input) is sent to the corresponding function-extending module  200  in step  1318 . Then an operation corresponding to the received control command is executed in the function-extending module  200 . For example, if predetermined contents are selected in the index page of the DVCR module  250  and an icon for reproducing the contents is selected, the name of the selected contents and a control command for reproducing the contents are sent to the DVCR module  250  and the DVCR module  250  reads the selected contents and sends the contents to the base module  100 . The base module  100  processes data received from the corresponding function-extending module  200  and outputs the processed data in step  1320 .  
     [0076] Although the modular TV system was explained as an embodiment of the AN system according to the present invention, the A/V system is not limited to the modular TV system. That is, the modular TV system is basically equipped with the digital broadcast receiving module for receiving a digital broadcast signal. However, in the present invention the digital broadcast receiving module for receiving digital broadcast signal can be mounted according to the user&#39;s selection as a function-extending module for an A/V system.  
     [0077] As described above, according to the present invention, an A/V system which implements a plurality of digital media apparatuses in one apparatus and function-extending modules therefor are provided. In particular, a user can select specifications and upgrade the system as the user wants.