Abstract:
A control system includes a control apparatus and a controlled apparatus, wherein the control apparatus is remotely controlled by a remote controller. The controlled apparatus transmits a control panel to the control apparatus. The control panel includes icons used to control the controlled apparatus. The controlled apparatus includes (a) a communication unit which receives, from the control apparatus, remote control information including information about operation keys included in the remote controller, the remote control information being received before the controlled apparatus transmits the control panel to the control apparatus, and (b) a modifying unit which modifies a position of the icons included in the control panel according to the remote control information. The communication unit transmits the control panel to the control apparatus after the modifying unit modifies the position of the icons included in the control panel according to the remote control information.

Description:
This application is a continuation of application Ser. No. 09/579,532, filed May 26, 2000 (pending). 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a data communication system, an apparatus and a control method therefor, and more particularly to a technology for providing a remote control environment suitable for a controlled apparatus connected to a network. 
     2. Related Background Art 
     With the recent progress in the digital signal processing technology, there is being developed so-called multi-media communication technology for delivering digitized image information (including still image and moving image), audio information, control information etc. to individual home through a disk medium, an ISDN communication network, a satellite digital Communication network, a cable television network etc. 
     On the other hand, for use in individual home, there is being developed so-called home network technology for connecting the television receiver, video cassette recorder (VCR), digital satellite broadcast receiving tuner etc. through a common digital interface, in order to provide a new service based on digital information from various media. 
     Once such home network is constructed in the home, the image information received by a satellite broadcast receiving tuner or the image information reproduced by a VCR can be viewed by plural display devices (television receiver, monitor of personal computer etc.) whereby provided is a service in a novel mode of use that has not been realized. 
     However, in order to realize the new service or new mode of use in such home network environment, the user has to execute a sequence of certain operations, regardless whether desired devices are directly operated or are remote controlled by a certain device. In either case, it is required to realize a user interface which is simple, visually easily understandable and capable of preventing complication in the operation sequence and confusion of the user. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to solve the above-described drawbacks. 
     Another object of the present invention as to realize an operation environment which is simple, easy to understand and suitable for a controlled device connected to a network. 
     The above-mentioned objects can be attained, according to a preferred embodiment of the present invention, by a data communication system comprising: 
     a) a first device for holding a control panel for providing a predetermined operation environment; 
     b) a second device for displaying the control panel; and 
     c) an operation device for operating the control panel displayed by the second device; 
     wherein the first device is adapted to change the control panel based on the operation device. 
     According to another embodiment, there is also provided a data communication apparatus comprising: 
     a) a holding unit for holding a control panel for providing a predetermined operation environment; 
     b) a changing unit for changing the control panel based on an operation device for operating the control panel displayed on an external device; and 
     c) a transmission unit for transmitting the control panel to the external device. 
     According to another embodiment, there is also provided a control method for controlling a data communication apparatus holding a control panel for providing a predetermined operation environment, the method comprising: 
     a) a changing step of changing the control panel, based on an operation device for operating the control panel displayed on an external device; and 
     b) a transmission step of transmitting the control panel to the external device. 
     According to another embodiment, there is also provided a data communication apparatus comprising: 
     a) a transmission unit for transmitting information relating to an operation device for operating a control panel providing a predetermined operation environment to an external device holding the control panel; and 
     b) a display control means for displaying the control panel transmitted from the external device on a display device. 
     According to another embodiment, there is also provided a control method for controlling a data communication apparatus comprising: 
     a) a transmission step of transmitting information relating to an operation device for operating a control panel providing a predetermined operation environment to an external device holding the control panel; and 
     b) a display control step of displaying the control panel transmitted from the external device on a display device. 
     Still other objects of the present invention, and the features thereof, will become fully apparent from the following detailed description of the embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram having an example of the data communication system embodying the present invention; 
         FIG. 2  is a block diagram showing the configuration of devices constituting the data communication system of the above-mentioned embodiment; 
         FIG. 3  is a view showing a remote controller constituting the control device of the above-mentioned embodiment; 
         FIG. 4  is a view showing the sequence of transmitting a remote control panel in the above-mentioned embodiment; 
         FIG. 5  is a view showing the sequence of remote control in the above-mentioned embodiment; 
         FIGS. 6A and 6B  are views respectively showing examples of remote controller information and a table storing such remote controller information; 
         FIG. 7  is a view showing an example of the remote control panel in the above-mentioned embodiment; 
         FIG. 8  is a view showing an example of the order of priority set in icons constituting the remote control panel shown in  FIG. 7 ; 
         FIG. 9  is a flowchart showing an example of the sequence for reconstituting the hd remote control panel shown in  FIG. 7 ; 
         FIG. 10  is a view showing an example of a table in which the icon information and the key ID are correlated; 
         FIG. 11  is a view showing an example of a table managing the remote control panel of each controlled device; 
         FIG. 12  is a view showing an example of image data of the above-mentioned embodiment in which an outer frame of the remote controller is graphically designed; 
         FIG. 13  is a view showing an example of the sequence for synthesizing the remote control panel in the above-mentioned embodiment; and 
         FIG. 14  is a view showing an example of application of the data communication system of the above-mentioned embodiment to a home network. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The preferred embodiments of the present invention will now be described in detail hereinafter with reference to the accompanying drawings. 
     In the following there will be explained, with reference to the accompanying drawings, the communication system, apparatus of the present invention, method and computer readable memory medium therefor. 
       FIG. 1  is a block diagram showing an example of a communication system realizing an operation environment based on the user interface embodying the present invention. 
     In  FIG. 1 , there are shown a digital television receiver  101 ; a tuner  102  for receiving digital satellite broadcasting; a digital video recorder (DVR)  103 ; and a remote control unit (remote controller)  104  for remote controlling the digital television receiver  101  by wireless transmitting the operation input of the user thereto. The remote controller  104  and the digital television receiver  101  executes wireless communication for example by the infrared communication method. 
     The devices are mutually connected with high-speed digital interfaces based on the IEEE1394-1995 standard (hereinafter called 1394 interfaces), thereby constituting a serial bus network. The 1394 interface of each device transfers the image information (including moving image and still image), audio information, control information etc. from other media to other devices without sacrificing the real-time property. 
     Referring to  FIG. 1 , the digital television receiver  101  functions as a remote control device while the tuner  102  and the DVR  103  function as controlled devices. 
     Each of the controlled devices (tuner  102 , DVR  103 ) has a function of generating an operation panel image (hereinafter called remote control panel) for remote controlling the own device, and a function of transmitting such remote control panel in response to a request from the remote control device (digital television receiver  101 ). Also each of the controlled devices (tuner  102 , DVR  103 ) controls its process operation based on the operation input entered through the remote control panel. 
     The remote control device (digital television receiver  101 ) has a function of requesting the remote control panel to a controlled device for which the user requests remote control operation, and displaying such remote control panel. The remote control device (digital television receiver  161 ) also has a function of transmitting the operation input of the user on the remote control panel to each controlled device (tuner  102 , DVR  103 ). 
     The remote control panel means a graphical user interface (GUI) composed of image information and character information and practically including plural operation keys representing the remote controllable functions of the controlled device. Each operation key is composed for example of an icon representing the function, corresponding to such operation key, by a pattern or characters. 
       FIG. 2  is a block diagram showing the detailed configuration of the devices constituting the communication system shown in  FIG. 1 . 
     At first there will be explained the configuration of the tuner  102 . In the present embodiment, the tuner  102  can be remote controlled through the remote control panel supplied by the tuner  102  itself. Such remote control panel is displayed in the display screen of the digital television receiver  101 . 
     A tuner unit  201  has a function of receiving various contents from a disk medium, an ISDN communication network, a satellite digital communication network, a ground wave digital broadcasting network, a cable television network etc. The tuner unit  201  transmits, to a 1394 interface  203 , the arbitrary content selected through an operation unit  205  or a remote control panel to be explained later. Each content includes image information, audio information etc. encoded with a high-efficiency encoding method (MPEG2, SD-DVCR, SDL-DVCR etc.). 
     A display panel generation unit  202  serves to generate the remote control panel for remote controlling the tuner  102  itself. The display panel generation unit  202  stores a basic remote control panel in advance in a memory and reconstructs such remote control panel when required. 
     A 1394 interface  203  converts the content supplied from the tuner unit  201 , into stream data according to a first communication protocol and executes real-time transfer of the stream data to a desired device. The 1394 interface  203  also executes transfer of the remote control panel, supplied from the display panel generation unit  202 , to the digital television receiver  101  according to a second communication protocol. 
     The first communication protocol means a protocol utilizing the isochronous transfer, for example based on the IEC61883 standard. In the present embodiment, the first communication protocol will be hereinafter called AV/C (audio video/control) protocol. In the AV/C protocol, the communication between certain devices is controlled by setting an input/output plug between a source transmitting the content and a destination receiving such content. The AV/C protocol also defines a procedure of packetizing the content, obtained by high-efficiency encoding by MPEG2, SD-DVCR, HD-DVCR or SDL-DVCR, by a predetermined data block and transferring each packet data as the stream data. 
     The second communication protocol means a protocol utilizing the asynchronous transfer. In the present embodiment, the second communication protocol will be hereinafter called asynchronous serial bus connection protocol. In the asynchronous serial bus connection protocol, there is set an input/output plug between the source and the destination, and object data, divided into one or more segments, are asynchronous transferred through such input/output plug. Such transfer protocol is highly reliable because it is not based on the isochronous transfer but on the asynchronous transfer and is suitable for the transfer of the object data which do not require real-time property but requires secure transfer. Also it can realize efficient transfer, utilizing the available time in the asynchronous transfer period, and without occupying each communication cycle as in the case of the isochronous transfer method. 
     A control unit  204  has a microcomputer and serves to control the function of the tuner  102 . 
     An operation unit  205  is provided in the tuner  102  itself. 
     A memory medium  206  serves to store various programs that can be read by the control unit  204 . For example it stores a program for generating the remote control panel and a program for realizing the communication sequence of the present embodiment, to be explained later. 
     In the following there will be explained the configuration of the DVR  103 . In the present embodiment, the DVR  103  can be remote controlled through the remote control panel supplied by the DVR  103  itself. Such remote control panel is displayed in the display screen of the digital television receiver  101 , as in the case of the tuner  102 . 
     A DVR unit  211  executes recording and reproduction of the image information or audio information obtained by high-efficiency encoding by MPEG2 SD-DVCR, HD-DVCR or SDL-DVCR. The DVR unit  211  outputs the arbitrary content, selected through an operation unit  215  or the remote control panel to a 1394 interface  213 . 
     A display panel generation unit  212  serves to generate the remote control panel for remote controlling the DVR unit  211  itself. The display panel generation unit  212  stores a basic remote control panel in advance in a memory and reconstructs such remote control panel when required. 
     A 1394 interface  213  converts the content, supplied from the DVR unit  211 , into stream data according to the AV/C protocol and executes real-time transfer of the stream data to a desired device. The 1394 interface  213  also executes transfer of the remote control panel, supplied from the display panel generation unit  212 , to the digital television receiver  101  according to the asynchronous serial bus connection protocol. 
     A control unit  214  has a microcomputer and serves to control the function of the DVR  103 . 
     An operation unit  215  is provided in the DVR  103  itself. 
     A memory medium  216  serves to store various programs that can bread byte control unit  214 . For example it stores a program for generating the remote control panel and a program for transmitting the remote control panel to the digital television receiver  101 . 
     In the following there will be explained the configuration of the digital television receiver  101 . 
     A 1394 interface  221  receives the stream data, isochronous transferred from the tuner  102  or the DVR  103  according to the AV/C protocol and supplies a decoder unit  222  with such stream data. The 1394 interface  221  also receives the remote control panel, asynchronous transferred from the tuner  102  or the DVR  103  according to the asynchronous serial bus connection protocol and supplies a display panel memory  224  with such remote control panel. 
     A decoder unit  222  decomposes the stream data, supplied from the 1394 interface  221 , into a video stream and an audio stream and decodes each stream data. 
     An audio output unit  223  executes D/A conversion and amplification of the audio stream, decoded in the decoder unit  222 , and outputs such audio stream through a loudspeaker. 
     A display panel memory  224  serves to store the remote control panel, asynchronous transferred from another electronic device. 
     A drawing control unit  225  serves to control the drawing process for the remote control panel in the tuner  102  and the DVR  103 . The drawing control unit  225  controls the position, range, period, start time etc. of drawing of each remote panel and whether the remote control panel can be superposed with another remote control panel. 
     An image synthesis unit  226  synthesizes the image information supplied from the decoder unit  222  and at least a remote control panel supplied from the drawing control unit  225  and supplies a display unit  227  with thus synthesized image. 
     A display unit  227  is composed of a display device such as a CRT, a liquid crystal panel or a plasma display. 
     An interface  228  for remote control receives control information (for example operation input by the user) from the remote controller  104 . The remote control interface  228  supplies a control unit  230  with the received control information. The remote control interface  228  supports a wireless communication such as infrared communication. 
     A remote control information memory  229  stores remote control information of the remote controller  104 . The remote control information includes information on the position, size and shape of the plural operation keys of the remote controller  104  (namely information on key configuration and information on the outer frame of the remote controller. The remote control information of the remote control information memory  229  can be transferred to other device by the asynchronous serial bus connection protocol. 
     A control unit  230  has a microcomputer and serves to control the process operation of the digital television receiver  101 . The control unit  230  also asynchronous transfers the operation input, executed on the remote control panel, to a device corresponding to such remote control panel. 
     A memory medium  231  serves to store various programs that can be read by the control unit  230 . For example it stores a program for controlling the drawing process of the remote control panel and a program for receiving the remote control panel of a desired electronic device. 
       FIG. 3  shows the configuration of the remote controller  104  of the present embodiment. 
     A wireless signal transmitting unit  301  executes wireless transmission of control information, such as a key code, to the remote control interface  228  of the digital television receiver  101 . 
     An operation key  302  is provided for turning on and off the power supply of the digital television receiver  101  by remote control. 
     Operation keys  303 ,  304  are provided for controlling the sound loudness of the digital television receiver  101 . 
     A key array  305  includes operation keys arranged in a 3×4 matrix. The operation keys of the key array  305  are respectively marked with numbers “1” to “12” and can be used for selecting television channels, entering alphabets, katakana and hiragana characters, numerals and special symbols, and moving a cursor, displayed on the digital television receiver  101 , in the vertical, horizontal or diagonal direction. 
     A quit key  306  is used, while the digital television receiver  101  executes remote control of a desired device by the remote control panel, for disconnecting the communication with such device. 
     In the present embodiment, each key in the key array  305  will be hereinafter represented by the numeral printed on such key. For example the key at the upper left corner of the key array  305  will be called “1” key. 
     In the following there will be explained, with reference to  FIGS. 4 and 5 , a communication sequence of the remote control device of the present embodiment (namely the digital television receiver  101 ) for receiving the remote control panel of a desired controlled device and a communication sequence of remote controlling the desired controlled device by such remote control panel. 
     At first reference is made to  FIG. 4  for explaining the communication sequence of the digital television receiver  101  for receiving the remote control panel of a controlled device (for example DVR  103 ). 
     Referring to  FIG. 4 , the digital television receiver  101  and the DVR  103  secure a communication band required in the isochronous communication period and an isochronous channel based on the AV/C protocol and set an isochronous connection (step  401  in  FIG. 4 ). 
     After the setting of the isochronous connection, the DVR  103  executes isochronous transfer of the content selected by the digital television receiver  101 , utilizing the above-mentioned isochronous channel ( 402  in  FIG. 4 ). The digital television receiver  101  decodes the received stream data by the decoder unit  226  and displays the image information on the display unit  227  and outputs the audio information from the audio output unit  223 . 
     In case the user request remote control of the DVR  103  by the remote control method of the present embodiment ( 403  in  FIG. 4 ), the digital television receiver  101  sets an asynchronous serial bus connection with the DVR  103  based on the asynchronous serial bus connection protocol ( 404  in  FIG. 4 ). 
     After the setting of the asynchronous serial bus connections, the digital television receiver  101  issues a Gui_Update(start) command, as an AV/C command, to the DVR  103  ( 405  in  FIG. 4 ). 
     The Gui_Update(start) command is a control command for instructing, in case the remote control panel displayed on the digital television receiver  101  is changed for example by a user operation, transmission of new display data corresponding to such change to the digital television receiver  101 . This control command allows the digital television receiver  101  to visually inform the user of any change in the remote control panel whenever such change is generated, and the user can visually confirm the response as the result of the operation executed by the user. This command remains effective until the DVR  103  receives a Gui_Update(stop) command. 
     Then the control unit  230  of the digital television receiver  101  read the remote control information of the remote controller  104  from the remote control information memory  229 , and sends such information to the 1394 interface  221  ( 406  in  FIG. 4 ). The 1394 interface  221  executes asynchronous transfer of such remote control information to the DVR  103  through the asynchronous serial bus connection ( 407  in  FIG. 4 ). The DVR  103  stores the remote control information in a memory of the display panel generation unit  212 . 
     Based on the remote control information, the display panel generation unit  212  of the DVR  103  reconstructs its remote control panel stored in advance, and stores the reconstructed remote control panel in the memory display panel generation unit  212  ( 408  in  FIG. 4 ). More specifically, the display panel generation unit  212  reconstructs its remote control panel so as to match the key configuration of the remote controller  104 . 
     Then the 1394 interface  221  of the digital television receiver  101  issues a control command (Push_Gui_Data command) for requesting the remote control panel of the DVR  103  ( 409  in  FIG. 4 ). 
     After the reception of the Push_Gui_Data command, the display panel generation unit  212  of the DVR  103  supplies the 1394 interface  213  with the reconstructed remote control panel. The 1394 interface  213  asynchronous transfers such remote control panel to the digital television receiver  101  through the asynchronous serial bus connection ( 410  in  FIG. 4 ). 
     The 1394 interface  221  of the digital television receiver  101  receives the remote control panel of the DVR  103  and stores the remote control panel in the display panel memory  224 . The drawing control unit  225  controls the readout of the remote control panel, and the image synthesizing unit  226  synthesizes the remote control panel with another image so as to display the the display unit  227  displays the output of the image synthesizing unit  226  ( 411  in  FIG. 4 ). 
     The drawing control unit  225  executes such control, when necessitated, as to display the remote control panel of the DVR  103  together with the remote control panel of another device. 
     The above-described communication sequence, shown in  FIG. 4 , allows the DVR  103  to generate a remote control panel matching the key configuration of the remote controller  104  of the digital television receiver  101 , and the digital television receiver  101  can display such remote control panel. Therefore the digital television receiver  101  can provide a graphical user interface easy to understand and to use and can also provide an operation environment based on such user interface. 
     In the following there will be explained a communication sequence of operating the remote control panel of the DVR  103  with the remote controller  104  for remote controlling the digital television receiver  101  thereby remote controlling the DVR  103 . 
     Referring to  FIG. 5 , the user actuates the operation keys of the remote controller  104 , thereby remote controlling the remote control panel of the DVR  103  displayed on the digital television receiver  101  ( 501  in  FIG. 5 ). 
     The remote controller  104  sends a wireless control signal, corresponding to an operation input (User_Action), to the remote control interface  228  of the digital television receiver  101  ( 502  in  FIG. 5 ). The control unit  203  of the digital television receiver  101  detects an operation key on the remote control panel, corresponding to such wireless control signal ( 503  in  FIG. 5 ). 
     The control unit  230  of the digital television receiver  101  issues a User_Action command for informing the remote control panel of the user operation, thereby executing informing to the DVR  103  through the 1394 interface  221  ( 504  in  FIG. 5 ). 
     The 1394 interface  213  of the DVR  103  receives the User_Action command and sends it to the control unit  214 , which in response executes control corresponding to such User_Action command ( 505  in  FIG. 5 ). 
     The display panel generation unit  212  of the DVR  103  detects whether the remote control panel has to be changed as a result of the control corresponding to the User_Action command. If a change is necessary, there are generated data of all the remote control panel after the change or of a part to be changed, and such generated data are supplied as changing data to the 1394 interface  213 . The 1394 interface  213  executes asynchronous transfer of such changing data to the digital television receiver  101  through the asynchronous serial bus connection ( 506  in  FIG. 5 ). 
     The 1394 interface  221  of the digital television receiver  101  sends the changing data to the display panel memory  224 . The drawing control unit  225  renews the displayed remote control panel with such changing data, thereby visually informing the user of the response to the operation input ( 607  in  FIG. 5 ). 
     In case the user enters a request of receiving stream data, different from the stream data in current reception, from another controlled device (namely from the tuner  102 ) ( 508  in  FIG. 5 ), the digital television receiver  101  sets another isochronous connection with the tuner  102  which supplies the desired stream data ( 509  in  FIG. 5 ). 
     After the setting of the new isochronous connection, the tuner  102  executes isochronous transfer of the content selected by the digital television receiver  101 , utilizing another isochronous channel ( 510  in  FIG. 5 ). The digital television receiver  101  decodes the received stream data by the decoder unit  226 , then displays the image information on the display unit  227  and outputs the audio information from the audio output unit  223 . 
     In case of remote controlling the tuner  102  by the remote control method of the present embodiment like the DVR  103  ( 511  in  FIG. 5 ), the digital television receiver  101  sets a new asynchronous serial bus connection with the tuner  102  based on the asynchronous serial bus connection protocol ( 512  in  FIG. 5 ). 
     After the setting of the asynchronous serial bus connection, the digital television receiver  101  issues a Gui_update (start) command, as an AV/C command, to the tuner  102 , as in the step  405  in  FIG. 4 . Thereafter the digital television receiver  101  and the tuner  102  execute a process similar to that in the steps  406  to  411  in  FIG. 4 , thereby displaying, on the display unit  227 , the remote control panel of the tuner  102  matching the key configuration of the remote controller  104 , together with the remote control panel of the DVR  103 . 
     When the user manipulates the remote controller  104  to instruct the termination of the remote control for the DVR  103 , the 1394 interface  221  of the digital television receiver  101  transmits a Gui_Update (stop) command to the DVR  103  ( 513  in  FIG. 5 ). 
     Then the 1394 interface  221  of the digital television receiver  101  releases the asynchronous serial bus connection with the DVR  103  ( 514  in  FIG. 5 ), and also releases the isochronous channel with the DVR  103  ( 515  in  FIG. 5 ). 
     The above-described communication sequence shown in  FIG. 5  allows the user to manipulate the remote control panel utilizing the remote controller  104  for remote controlling the digital television receiver  101 , thereby achieving remote control of the controlled device. Also the controlled device can visually inform the user of the change in the remote control panel corresponding to the input operation by the user, thereby preventing the confusion of the user and improving the operability. 
     In the foregoing there has been explained the communication sequence between the digital television receiver  101  and the DVR  103  with reference to  FIGS. 4 and 5 , but such configuration is not restrictive. For example the tuner  102  may be selected as the controlled device, and the communication sequence shown in  FIGS. 4 and 5  may be applied for remote controlling the tuner  102 . 
     In the following there will be explained, with reference to  FIGS. 6A and 6B , the remote control information (including outer frame information of the remote controller and key configuration information) stored in the remote control information memory  229  of the digital television receiver  101 . 
       FIG. 6A  is a view showing the shape of the outer frame of the remote controller  104  and the shape of the basic operations keys thereof on a two-dimensional coordinate system. The remote control information memory  229  stores, as the remote control frame information, the shape of the outer frame of the remote controller  104 , the position of the original point of the outer frame and the vertical and horizontal lengths thereof. The remote control information memory  229  stores, also as the remote control frame information, image data  1201  showing the graphic design of the outer frame of the remote controller  104  and special operation keys other than the basic operation keys (for example quit key  306 ), as shown in  FIG. 12 . 
     In  FIG. 6A , the origin point  601  is for example taken at the upper left corner of the remote controller  104 , with the x-axis taken in the horizontal direction and the y-axis in the vertical direction. The position of each basic operation key is represented by a two-dimensional coordinate value (x, y) representing the center of the operation key. Also, the size of each basic operation key is represented by a two-dimensional value (l, m) wherein “l” and “m” are relative values defined in relation to the vertical length L of the remote controller  104 . 
       FIG. 6B  shows a table  600  storing the key configuration information of the basic operation keys. The remote control information memory  229  stores such table  600  as key configuration information. 
     Referring to  FIG. 6B , a name column  602  stores the names of the operation keys. A key ID column  603  stores sequential ID numbers assigned to the operation keys. A shape column  604  stores codes indicating the frame shapes of the operation keys. For example, “2” indicates an oval key while “00” indicates a rectangular key. A position column  605  stores data (x, y) indicating the position of each operation key on the remote controller  104 . A size column  606  stores data (l, m) indicating the size of each operation key. 
     In the following there will be explained, with reference to  FIG. 7 , an example of the remote control panel stored in advance in the display panel generation unit  212  of the DVR  103 . 
     There are shown an entire remote control panel  701 ; an icon  702  for instructing a reproducing operation; an icon  703  for instructing a varied-speed reproducing operation in the forward direction; an icon  704  for instructing a varied-speed reproducing operation in the reverse direction; an icon  705  for instructing a stop; an icon  706  for instructing a reproducing operation for an immediately succeeding or subsequent index, chapter or content; an icon  707  for instructing a reproducing operation of an immediately preceding or preceding index, chapter or content; and an icon  708  for instructing a pause. A link icon  709  is used, in case the remote control panel of the DVR  103  has a hierarchic structure, for requesting a remote control panel in an upper or lower hierarchic layer. The icons  701  to  709  are constructed with image information (for example patterns) for helping the visual understanding of the corresponding function. 
     The remote control unit  701  of the DVR  103  is composed of plural icons  702  to  709  for controlling the functions of the DVR  103 . The icons are given a predetermined order of priority, in consideration of the frequency of use and the importance of the corresponding functions. Also the icons representing the functions of high frequencies of use or those representing the functions important for the user are so constructed as to be conspicuous to the user, and are positioned close to the center of the panel  701 , thereby facilitating the selection by the user. 
       FIG. 8  shows an example of the order of priority, set on the icons  702  to  709 . An icon column  801  indicates the icons  702  to  709 , and a priority order column  802  indicates an example of the order of priority set on the icons  702  to  709 . In the present embodiment, an icon with a smaller number is handled as the icon of a higher order or priority for display (namely positioned closer to the center). 
     In the following there will be given a detailed explanation, with reference to  FIG. 9 , on an example of the sequence executed by the display panel generation unit  212  of the DVR  103  for reconstructing its remote control panel  701 , based on the remote control information of the digital television receiver  101 . 
     Referring to  FIG. 9 , the display panel generation unit  212  detects, based on the remote control information, a basic operation key conspicuous to the user, for example the “5” key positioned close to the center of the remote controller  104  (step  901 ). 
     Then the display panel generation unit  212  assigns the icons  701  to  709  in succession to the basic operations keys of the remote controller  104 , based on the order of priority shown in  FIG. 8  (step  902 ). More specifically, the display panel generation unit  212  executes assignment in the descending order of priority of the icons, around the “5” key detected in the step  901 . 
     In each assignment of the icons  702  to  709  to the basic operation keys of the remote controller  104 , the display panel generation unit  212  holds the result of such assignment in a correspondence table  1000  shown in  FIG. 10  (step  903 ). In  FIG. 10 , an icon information column  1001  indicates icons  702  to  709 , and a key ID column  1002  indicates the sequential ID numbers (same as the key ID numbers shown in  FIG. 6 ) assigned to the basic operation keys. 
     After the step  903 , the display panel generation unit  212  deforms, based on the key configuration information, the size and shape of the icons  702  to  709  so as to match those of the corresponding basic operation keys (step  904 ). 
     After the execution of the process on all the icons  702  to  709 , the display panel generation unit  212  stores the remote control panel, including the deformed icon information, together with the table information shown in  FIG. 10 , and asynchronous transfers such information in response to a Push_Gui_Data command ( 409  in  FIG. 4 ) from the digital television receiver  101  (step  905 ). 
     The process sequence described above is not limited to the display panel generation unit  212  of the DVR  103  but can also be executed by the display panel generation unit  202  of the tuner  102 . 
     Now reference is made to  FIG. 11  for explaining the management of the remote control panel of each controlled device in the display panel memory  224  of the digital television receiver  101 . 
     After issuing the Push_Gui_Data command to the DVR  103 , the digital television receiver  101  receives the remote control panel (including plural icons) reconstructed by the DVR  103  according to the sequence shown in  FIG. 9  and the key ID indicating the operation keys corresponding to the respective icons, and supplies the display panel memory  224  with such information. 
     The display panel memory  224  manages the remote control panels of the controlled devices, utilizing a table  1100  shown in  FIG. 11 . The table  1100  is so constructed as to store the device ID  1101 , the node ID  1102  and the icon information corresponding to each key ID. 
     The device ID  1101  means an individual ID capable of identifying the manufacturer and product of the device corresponding to the IEEE1394-1995 standard. The device ID  1101  corresponds in the configuration ROM provided in the 1394 interface of each device, the Node Vendor ID in the Bus_info_Block field, or the Module Vendor ID or Module Spec ID in the Root_Directory field. The digital television receiver  101  is so constructed as to read the device ID  1101  from the configuration ROM of each controlled device and to store such ID in the table  1100 . For example, in the present embodiment, “bbbbbbbb” indicates the DVR  103 , and “cccccccc” indicates the tuner  102 . 
     Also the node ID is a node number assigned to each controlled device after the bus resetting, and a desired device can be specified by such node number on the local bus. 
     For example, in case of storing the information of the DVR  103  in the table  1100 , “bbbbbbbb” is stored in the device ID  1101  and “3” is stored in the node ID. Also in the key ID=“3” (corresponding to the key “ 1 ” in  FIG. 3 ), there is stored the icon  707  designating the start point of the reproduction of the preceding content etc., while, in the key ID=“5” (corresponding to the key “ 3 ” in  FIG. 3 ) there is stored the icon  706  designating the start point of the reproduction of the succeeding content and, in the key ID=“6” there is stored the icon  704  designating the varied-speed reproduction in the reverse direction. 
     In the following reference is made to  FIG. 13  for explaining an example of the sequence of the drawing control unit  225  of the digital television receiver  101  for drawing the remote control panel of the DVR  103  on the display image frame.  FIG. 13  shows the flow of preparing the remote control panel of the DVR  103  and an example of thus displayed remote control panel. 
     In  FIG. 13 , image data  1201  is the remote control frame information indicating the (schematic) outer frame of the remote controller and is stored in the remote control information memory  229 . There are also shown a remote control panel  1301  constructed from the key configuration information of the remote controller  104 , and an example of the remote control panel  1302  actually displayed on the display unit  227 . 
     At first the drawing control unit  225  reads the image data  1201 , schematically representing the outer frame of the remote controller  104 , stored in advance in the remote control information memory  229 , and executes synthesis with the image information from the decoder unit  222  in such a manner as to execute display in a predetermined position on the image area. 
     Then the drawing control unit  225  constructs the remote control panel  1301  based on the key configuration information and the information stored in the table  1100 . 
     At this stage, the drawing control unit  225  arranges, within the remote control panel  1301 , the icons  702  to  709  reconstructed by the DVR  103  in positions same as those of the respectively corresponding operation keys. If an icon corresponding to the operation key is absent, the drawing control unit  225  prepares a blank icon and positions such blank icon in a position same as that of the operation key. 
     Then the drawing control unit  225  synthesizes the remote control panel  1301 , so constructed as to match the operation keys of the remote controller  104 , with the image data  1201  and displays the synthesized image on the display unit  227  through the image synthesizing unit  226 . As a result, the digital television receiver  101  can display the control panel, for remote control of the DVR  103 , in a form similar to that of the remote controller  104 . 
     The above-described sequence allows the digital television receiver  101  to display the remote control panel of the DVR  103  or the controlled device, in a form similar to that of the remote controller  104  serving to remote control the DVR itself. Also the user can execute remote control of the function of the DVR  103  in an operation environment same as that of the remote controller  104 . 
     The remote control pane  1302  shown in  FIG. 13  may be arbitrarily changed, on the display screen of the display unit  227 , in the size, display position and shape according the input operation of the user. The drawing sequence resulting from such change is controlled by the drawing control unit  225 , and the information resulting from such change is retained in the display panel memory  224 . 
     In  FIG. 13 , a hatched area indicates the absence of assignment of the function that can be remote controlled by the icon. Therefore, the icon not corresponding to the remote control by the remote controller  104  may be displayed by synthesizing (α-blending) with the background (image information from the decoder unit  222 ). 
       FIG. 14  shows an example of the application of the operation environment, based on the user interface of the present embodiment, to a home network. A home network  1400  shown in  FIG. 14  is constructed by a high-speed serial bus network based on the IEEE1394-1995 standard. Such network  1400  is capable of node branched connection or daisy chain connection, and the 1394 interface of each device has a function of relaying the serial data outputted by other devices. 
     In  FIG. 14  there are shown a first DVD (digital video disk) player  1401 ; a second digital television receiver  1402 ; a remote controller  1403  for remote controlling the digital television receiver  1402 ; a third digital television receiver  1404 ; a remote controller  1405  for remote controlling the digital television receiver  1404 ; and a second DVD player  1406 . 
     The digital television receivers  1402 ,  1404  are remote control devices similar in function to the digital television receiver  101  explained in the foregoing. The three digital television receivers  101 ,  1402 ,  1404  are positioned in respectively different rooms. 
     Also the DVD players  1401 ,  1406  have a function, like the tuner  102  and the DVR  103  described in the foregoing, of generating a remote control panel matching the operation keys of the respective remote controller, based on the remote control information of the remote controllers  104 ,  1403 ,  1405 . 
     The above-described home network allows each of the three digital television receivers  101 ,  1402 ,  1404 , positioned in respectively different rooms, to display the remote control panel of one or more controlled devices positioned in the same or different room, based on the sequence shown in  FIG. 4 . Also each of the digital television receivers  101 ,  1402 ,  1404  can easily and arbitrarily control the desired controlled device by the operation on the remote control panel, displayed on the display area, according to the sequence shown in  FIG. 5 . Further, each of the digital television receivers  101 ,  1402 ,  1404  can visually display the result of such remote control on the remote control panel. 
     OTHER EMBODIMENTS 
     The above-described embodiment can also be realized in the following manner. 
     For example there may be assumed a configuration of storing a program realizing the process sequence of the foregoing embodiment shown in  FIGS. 4 and 5  in the memory media  206 ,  216 ,  231 , and supplying such memory media respectively to the control units  204 ,  214 ,  230 , whereby the control units  204 ,  214 ,  230  read the program codes stored in the memory media  206 ,  216 ,  231  and operates the process circuits shown in  FIG. 10  so as to realize the functions of the aforementioned embodiment. 
     In such case, the program itself read from the memory media  206 ,  216 ,  231  realize the functions of the aforementioned embodiment, and the memory media  206 ,  216 ,  231  storing such program constitute a part of the present invention. 
     The memory medium  206 ,  216  or  231  supplying the program can be composed, for example, of a floppy disk, a hard disk, an optical disk, a magnetooptical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory car or a ROM. 
     As explained in the foregoing, the present invention can provide a graphical user interface which is simple and easy to understand and can avoid complication of the operation sequence and confusion of the user. Such graphical user interface allows the user to remote control the desired device in an easily understandable and speedy manner. 
     The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. 
     Therefore, the above-mentioned embodiments are merely examples in all respects, and must not be construed to limit the invention. 
     The scope of the present invention is defined by the scope of the appended claims, and is not limited at all by the specific descriptions of this specification. Furthermore, all the modifications and changes belonging to equivalents of the claims are considered to fall within the scope of the present invention.