Abstract:
A method for managing a broadcast receiving apparatus standby mode according to external signaling is provided. The method includes: generating a power management descriptor that a broadcast receiving apparatus refers to in order to perform a standby mode; and transmitting the generated power management descriptor to the broadcast receiving apparatus. Accordingly, since the broadcast receiving apparatus manages the standby mode more effectively, standby power consumed in the standby mode is further reduced and thus power saving effect can be achieved.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from Korean Patent Application No. 10-2011-0034352, filed on Apr. 13, 2011 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     Methods and apparatuses consistent with exemplary embodiments relate to a method for managing a broadcast receiving apparatus standby mode, and more particularly, to a method for managing a standby mode of a broadcast receiving apparatus to reduce power consumption in a non-use time zone. 
     2. Description of the Related Art 
     How much TV a household watches varies from region to region. However, the maximum TV viewing time is about 8 hours, which is one-third of a day, and it is common that the TV operates in a standby mode, in which people do not watch the TV, for the rest of time. 
     However, most of the set top boxes (STB) sold today do not support the standby mode. Even though the STB supports the standby mode, it uses only 10-20% less power in the standby mode than in an on mode. 
       FIG. 1  is a view illustrating power consumption and standby power in a related-art STB. It can be seen from  FIG. 1  that average power consumption of the STB in the standby mode is 14.48 W, which is a very high level. 
     It is a worldwide trend to green all image devices, and the international energy agency recommends that home appliances should reduce standby power to no more than 1 W. 
     Therefore, there is a demand for a method for managing a standby mode of a broadcast receiving apparatus such as a STB effectively and reducing standby power consumption. 
     SUMMARY 
     One or more exemplary embodiments may overcome the above disadvantages and other disadvantages not described above. However, it is understood that one or more exemplary embodiment are not required to overcome the disadvantages described above, and may not overcome any of the problems described above. 
     One or more exemplary embodiments provide a method for managing a standby mode of a broadcast receiving apparatus effectively to reduce standby power which is consumed in the broadcast receiving apparatus. 
     According to an aspect of an exemplary embodiment, there is provided a method for managing a broadcast receiving apparatus standby mode, the method including: generating a power management descriptor that a broadcast receiving apparatus refers to in order to perform a standby mode; and transmitting the generated power management descriptor to the broadcast receiving apparatus. 
     The power management descriptor may contain information on a standby mode which should be supported by the broadcast receiving apparatus. 
     The standby mode which should be supported by the broadcast receiving apparatus may include a first standby mode and a second standby mode. 
     A number of functions that are performed in the first standby mode may be larger than a number of functions that are performed in the second standby mode, and the broadcast receiving apparatus may be switchable between the first standby mode and the second standby mode. 
     The power management descriptor may contain information on a function that is performed by the broadcast receiving apparatus in the first standby mode. 
     The method may further include: generating an update descriptor which contains information on update to be performed by the broadcast receiving apparatus in the first standby mode; and transmitting the generated update descriptor to the broadcast receiving apparatus. 
     The update descriptor may contain information on firmware update to be performed in the first standby mode. 
     The update descriptor may contain at least one of a firmware update start time, a firmware update effective duration, and firmware scramble information. 
     The update descriptor may contain information on EIT update to be performed in the first standby mode. 
     The update descriptor may contain at least one of a type of an EIT, a version of an EIT which is transmitted last, an EIT update start time, an EIT update effective duration, and EIT scramble information. 
     The type of the EIT may include at least one of an EIT present/follow (P/F) type and an EIT schedule (sch) type. 
     The update descriptor may contain information on application update to be performed in the first standby mode. 
     The method may further include: generating a terminal management descriptor which contains information on management to be performed by the broadcast receiving apparatus in the first standby mode; and transmitting the generated terminal management descriptor to the broadcast receiving apparatus. 
     According to an aspect of another exemplary embodiment, there is provided a method for managing a broadcast receiving apparatus standby mode, the method including: receiving, by a broadcast receiving apparatus, a power management descriptor to refer to in order to perform a standby mode; and running, by the broadcast receiving apparatus, the standby mode with reference to the received power management descriptor. 
     The power management descriptor may contain information on a standby mode which should be supported by the broadcast receiving apparatus. 
     According to exemplary embodiments as described above, since the broadcast receiving apparatus such as the STB can manage the standby mode more effectively, standby power consumed in the standby mode can be further reduced and thus power saving effect can be achieved. In particular, unnecessary power consumption of the broadcast receiving apparatus in a non-viewing time zone can be reduced and also some necessary functions can be more effectively performed, and thus there is no problem in service quality. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The above and/or other aspects will be more apparent by describing in detail exemplary embodiments, with reference to the accompanying drawings, in which: 
         FIG. 1  is a view illustrating power consumption and standby power in a related-art STB; 
         FIG. 2  is a view illustrating a broadcasting service system according to an exemplary embodiment; 
         FIG. 3  is a block diagram of a STB illustrated in  FIG. 2 ; 
         FIG. 4  is an operation mode transition diagram of a STB; 
         FIG. 5  is a view illustrating a power supply state of a STB in an active standby mode; 
         FIG. 6  is a view illustrating a power supply state of a STB in a passive standby mode; 
         FIG. 7  is a flowchart illustrating a method for changing a STB mode; 
         FIG. 8  is a view illustrating service information (SI) tables according to the DVB-SI standard; 
         FIG. 9  is a view illustrating SI descriptors according to the DVB-SI standard; 
         FIG. 10  is a view illustrating external signaling descriptors; 
         FIG. 11  is a view illustrating a structure of a power management descriptor (a power_management_descriptor); 
         FIG. 12  is a view to explain information which is contained in a terminal power mode (terminal_power_mode); 
         FIG. 13  is a view to explain information which is contained in a service mode (service_mode); 
         FIG. 14  is a view illustrating a structure of a firmware update descriptor (fw_update_descriptor); 
         FIG. 15  is a view illustrating a structure of an event information table (EIT) update descriptor (EIT_update_descriptor); 
         FIG. 16  is a view to explain information which is contained in an EIT type (EIT_type); and 
         FIG. 17  is a view illustrating a structure of a terminal management descriptor (terminal_management_descriptor). 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, exemplary embodiments will be described in greater detail with reference to the accompanying drawings. 
     In the following description, same reference numerals are used for the same elements when they are depicted in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of exemplary embodiments. Thus, it is apparent that exemplary embodiments can be carried out without those specifically defined matters. Also, functions or elements known in the related art are not described in detail since they would obscure the exemplary embodiments with unnecessary detail. 
     1. Broadcasting Service System 
       FIG. 2  is a view illustrating a broadcasting service system according to an exemplary embodiment. The broadcasting service system according to an exemplary embodiment is established by a high end of a broadcaster  200  and a plurality of STBs  100 - 1  to  100 - n.    
     The high end of the broadcaster  200  provides broadcasts and contents to the STBs  100 - 1  to  100 - n . Also, the high end of the broadcaster  200  provide a variety of service information (SI) to the STBs  100 - 1  to  100 - n.    
       FIG. 3  is a block diagram illustrating a STB using reference numeral  100  as a representative of the STBs of  FIG. 2 . The STB  100  is a kind of broadcast receiving apparatus and may provide a real-time broadcasting service and a content providing service. 
     As shown in  FIG. 3 , the STB  100  includes a tuner  100 , a demodulator  115 , a memory  120 , a processor  130 , a real time clock (RTC)  135 , a front panel  140 , an audio and video (AV) outputter  145 , an Ethernet interface  150 , an infrared ray (IR) receiver  155 , a universal serial bus (USB) interface  160 , a power supplier  170 , and a power controller  175 . 
     The tuner  110  tunes a broadcast signal of a broadcast channel that is selected by a user from among broadcast signals received from a terrestrial antenna, a cable, a satellite antenna, or the internet, and the demodulator  115  demodulates the broadcast signal which is tuned by the tuner  110 . 
     The processor  130  divides the broadcast signal which is demodulated by the demodulator  115  into a video signal, an audio signal, and a service information (SI) signal. Also, the processor  130  performs video decoding and signal processing with respect to the video signal, and performs audio decoding and signal processing with respect to the audio signal. 
     The processor  130  controls an overall operation of the STB  100 . In particular, the processor  130  controls an operation mode change of the STB  100 . This will be explained in detail below. 
     The memory  120  provides a storage space which is necessary for decoding and signal processing by the processor  130 . The RTC  135  functions as a timer. 
     The front panel  140  is disposed on a front surface of the STB  100 , and includes a display to display a current time and an operation state of the STB  100  and buttons to directly receive input of a user command. 
     Also, the IR receiver  155  and the USB interface  160 , which will be described below, are disposed on the front panel  140 . 
     The AV outputter  145  transmits the audio signal and the video signal which are decoded and signal processed by the processor  130  to a TV, which is connected to the STB  100 . The AV outputter  145  may output the audio signal and the video signal in various AV outputting methods such as Composite, Component, HDMI and DVI. 
     The Ethernet interface  150  provides a network interface to access an external network. 
     The IR receiver  155  receives a user command which is input through a remote controller in the form of infrared rays, and forwards the user command to the processor  130 . The USB interface  160  is communicably connected with an external device according to the USB standard. 
     The power supplier  170  supplies necessary power to the blocks  110 ,  115 ,  120 ,  130 ,  135 ,  140 ,  145 ,  150 ,  155 , and  160  provided in the STB  100 . 
     The power controller  175  controls a power supply operation of the power supplier  170  according to an operation mode of the STB  100  which is determined by the processor  130 . The power supply operation is controlled by restricting the power supplied to the blocks by the power supplier  170 . 
     2. Functions of STB 
     The functions performed in the STB  100  are divided into a ‘main function’ and a ‘background function’. Each function will be explained in detail below. 
     2.1. Main Function (Function for User) 
     Providing Broadcast: The STB outputs audio and video signals of a received real-time broadcast. 
     Providing Video On Demand (VOD): The STB requests and receives a content selected by the user from the high end of the broadcaster  200 , and outputs audio and video signals. 
     Recording: The STB records a broadcast (including recording a broadcast audio and video signals of which are currently output to provide a delayed broadcast), and records a content; 
     Executing User Application: The user application is an application that directly provides entertainment or services to the user, and includes an in-bound application and an out-bound application. 
     Downloading User Application 
     2.2. Background Function (Function for STB) 
     Updating STB software (S/W): The STB S/W includes firmware and applications necessary for driving the STB  100 : 
     Updating Event Information Table (ETT) 
     Managing STB: The STB  100  manages resources of the STB  100 . 
     3. Operation Mode of STB 
     The STB  100  includes four operation modes to reduce power consumption, and an operation mode transition diagram is illustrated in  FIG. 4 . As shown in  FIG. 4 , the four operation modes of the STB  100  are an on mode, an active standby mode, a passive standby mode, and an off mode. 
     As shown in  FIG. 4 , the STB  100  may change: 
     1) from the ‘on-mode’ to the ‘active standby mode or off mode’; 
     2) from the ‘active standby’ mode to the ‘on-mode, passive-standby mode or off mode’; 
     3) from the ‘passive standby mode’ to the ‘on mode, active standby mode or off mode’; and 
     4) from the ‘off mode’ to the ‘on mode’. 
     Hereinafter, each of the four operation modes of the STB  100  will be explained below. 
     3.1. On Mode (Active Mode) 
     The on mode is a mode in which power is supplied to the STB  100  and both the main function and the background function are performed. In the on mode, the STB  100  may selectively perform the main function or the background function and may perform the two functions together. 
     In the on mode, 
     1) when the user turns off a power switch and the power to the STB  100  is shut off, the STB  100  changes the on mode to the off mode, and 
     2) when the user presses an off button, the STB  100  changes the on mode to the active standby mode which will be described below. 
     There is a difference between the power switch and the off button in that the power switch is a physical switch that is provided on a rear side of the STB  100 , and the off button includes an off button which is provided on the front panel  140  of the STB  100  and an off button which is provided on a remote controller. 
     3.2. Active Standby Mode 
     The active standby mode is a mode in which power is supplied to the STB  100 , and the main function cannot be performed and only the background function can be performed. 
     In the active standby mode, 
     1) when a user command is input (irrespective of its kind), the STB  100  changes the active standby mode to the on mode, 
     2) when the user turns off the power switch and the power to the STB  100  is shut off, the STB  100  changes the active standby mode to the off mode, and 
     3) when the background function is not performed, the STB  100  changes the active standby mode to the passive standby mode, which will be described below. 
     A detailed explanation regarding case 3) will be provided below with reference to  FIG. 7 . 
       FIG. 5  is a view illustrating a power supply state of the STB  100  in the active standby mode. In  FIG. 5 , the hatched boxes indicate blocks that are supplied with the power from the power supplier  170 . 
     Referring to  FIG. 5 , in the active standby mode, the power is supplied to the tuner  110 , the demodulator  115 , the memory  120 , the processor  130 , the RTC  135 , the front panel  140 , the Ethernet interface  150 , and the IR receiver, which are blocks necessary for performing the background function. 
     3.3. Passive Standby Mode 
     The passive standby mode is a mode in which power is supplied to the STB  100  and none of the main function and the background function can be performed. In the passive standby mode, the STB  100  only performs the functions of displaying a current time and an operation state of the STB  100  through the front panel  140 , and sensing whether a user command is input or not through the front panel  140  and the IR receiver  155 . 
     Although not mentioned above clearly, the displaying function and the sensing function performed in the passive standby mode are normally performed in the on mode and the active standby mode. 
     In the passive standby mode, 
     1) when a user command (irrespective of its kind) is input, the STB  100  changes the passive standby mode to the on mode, 
     2) when the user turns off the power switch and the power to the STB  100  is shut off, the STB  100  changes the passive standby mode to the off mode, and 
     3) when a time to perform the background function arrives, the STB  100  changes the passive standby mode to the active standby mode. 
     A detailed explanation regarding case 3) will be provided below with reference to  FIG. 7 . 
       FIG. 6  is a view illustrating a power supply state of the STB  100  in the passive standby mode. The hatched blocks of  FIG. 6  indicate blocks that are supplied with the power from the power supplier  170 . 
     Referring to  FIG. 6 , in the passive standby mode, the power is supplied to the RTC  135 , the front panel  140 , and the IR receiver  155 , which are blocks necessary for performing the above-described displaying function and sensing function. 
     3.4. Off Mode 
     The off mode is a mode in which power is not supplied and none of the functions can be performed. That is, in the off mode, the display function and the sensing function performed in the passive standby mode are not performed. 
     As described above, the STB  100  enters the off mode when the user turns off the power switch. 
     In the off mode, when the user turns on the power switch and power is supplied to the STB  100 , the STB  100  changes the off mode to the on mode. 
     4. STB Mode Change Based on Self Power Management 
     When the STB mode is changed based on self power management, the mode switches between the active standby mode and the passive standby mode according to external signaling of the high end of the broadcaster, which provides a broadcast and a content. This will be explained in detail below with reference to  FIG. 7 . 
       FIG. 7  is a flowchart illustrating a method for changing a STB mode according to another exemplary embodiment. 
     As shown in  FIG. 7 , when the STB  100  is running in the on mode (S 310 ) and the off button is pressed by the user (S 320 -Y), the processor  130  changes the operation mode of the STB  100  from the on mode to the active standby mode (S 330 ). 
     The power supply state of the STB  100  which is changed from the on mode to the active standby mode in operation S 330  is illustrated in  FIG. 5 . In the active standby mode, the STB  100  cannot perform the main function and can perform only the background function. 
     The background function includes updating the STB SAY, updating the EIT, and managing the STB as described above. The high end of the broadcaster  200  informs the STB  100  of a STB SAY update time, an EIT update time, and a STB management time using external signaling. 
     Accordingly, when the STB  100  enters the active standby mode, the processor  130  executes an auto power down (APD) daemon and determines when it will perform the background function with reference to the external signaling, which is received from the high end of the broadcaster  200 . 
     On the other hand, when a user command is input in the active standby mode (S 340 -Y), the processor  130  changes the operation mode of the STB  100  to the on mode (S 310 ). On the other hand, when no user command is input in the active standby mode (S 340 -N), the processor  130  determines whether the STB  100  is performing the background function (S 350 ). 
     When it is determined that the background function is being performed (S 350 -Y), the processor  130  maintains the active standby mode (S 330 ). 
     On the other hand, when it is determined that the background function is not performed (S 350 -N), the processor  130  changes the operation mode of the STB  100  to the passive standby mode (S 360 ). 
     When the STB  100  enters the passive standby mode, the processor  130  runs the RTC  135  according to the background function performing time which is determined when the mode is changed to the active standby mode. 
     The power supply state of the STB  100  which enters the passive standby mode in operation S 360  is illustrated in  FIG. 6 . Also, in the passive standby mode, the STB  100  may not perform the main function as well as the background function. 
     When a user command is input in the passive standby mode (S 370 -Y), the processor  130  changes the operation mode of the STB  100  to the on mode (S 310 ). 
     On the other hand, when no user command is input in the passive standby mode (S 370 -N), the processor  130  determines whether the time to perform the background function arrives or not using the RTC  135  (S 380 ). 
     When it is determined that the time to perform the background function arrives (S 380 -Y), the processor  130  changes the operation mode of the STB  100  to the active standby mode (S 330 ). 
     On the other hand, when it is determined that the time to perform the background function does not arrive (S 380 -N), the processor  130  maintains the passive standby mode. 
     5. Signaling Standard 
     Hereinafter, the standard of the external signaling which is provided by the high end of the broadcaster  200  for the sake of self power management in the STB  100  will be explained in detail. Although the signaling standard is suggested in the form of an extended standard of the DVI-SI standard hereinbelow, the technical idea of exemplary embodiments may be applied to standards other than the DVB-SI standard. 
     5.1. SI Table 
       FIG. 8  lists SI tables according to the DVB-SI standard.  FIG. 8  identifies PIDs and table IDs of the SI tables, which are transmitted according to the DVB-SI standard, such as a network information table (NIT), a service description table (SDT), a time and date table (TDT), an event information table present/follow (EIT P/F), and an event information table schedule (EIT sch). 
     According to the DVB-SI standard, 1) a transmission frequency of the NIT is 9 hr, 2) a transmission frequency of the SDT is 1.5 hr, 3) a transmission frequency of the TDT is 1 hr, 4) a frequency of the EIT P/F is 1 hr, 5-1) a transmission frequency of the EIT sch on an AV channel is 9 hr, and 5-2) a transmission frequency of the EIT sch on an audio channel is 9 hr. 
     5.2 SI Descriptor 
       FIG. 9  lists SI descriptors according to the DVB-SI standard.  FIG. 9  identifies tags and positions of the SI descriptors, which are transmitted according to the DVB-SI standard, such as a network name descriptor, a service list descriptor, a service descriptor, a short event descriptor, an extended event descriptor, a content descriptor, and a parental rating descriptor. 
     5.3. External Signaling Descriptor for Self Power Management of STB 
       FIG. 10  suggests external signaling descriptors which are referred to when the STB  100  sets a mode switch condition between the active standby mode and the passive standby mode. These descriptors are generated by the high end of the broadcaster  200  and are transmitted to the STB  100 . 
     As shown in  FIG. 10 , the external signaling descriptors include: 
     1) a power management descriptor (power_management_descriptor) 
     2) a firmware update descriptor (fw_update_descriptor) 
     3) an EIT update descriptor (EIT_update_descriptor) 
     4) an application update descriptor (app_update_descriptor); and 
     5) a terminal management descriptor (terminal_management_descriptor) 
     Referring to  FIG. 10 , the tags and the positions of the external signaling descriptors are identified. 
     Hereinafter, each external signaling descriptor will be explained in detail. 
     5.3.1. Power Management Descriptor (Power Management Descriptor) 
       FIG. 11  illustrates a structure of the power management descriptor (power_management_descriptor). The power management descriptor (power_management_descriptor) is a descriptor that contains information that the STB  100  will refer to when running the standby mode. 
     Specifically, as shown in  FIG. 11 , the power management descriptor (power_management_descriptor) contains information on a descriptor tag (descriptor_tag), a descriptor length (descriptor_length), a terminal power mode (terminal_power_mode), and a service mode (service_mode). 
     The descriptor tag (descriptor_tag) is a tag for identifying the power management descriptor (power_management_descriptor), and is ‘0x80’ as shown in  FIG. 10 . 
     The descriptor length (descriptor_length) is information on a length of the power management descriptor (power_management_descriptor). 
     The terminal power mode (terminal_power_mode) contains information on the standby mode which should be supported by the STB  100 . Specifically, the terminal power mode (terminal_power_mode) contains ‘0’, ‘1’, or ‘2’ as shown in  FIG. 12 . 
     1) ‘0’ indicates a case in which the STB  100  should be always in the on mode (that is, the STB  100  does not have to support the standby mode), 
     2) ‘1’ indicates a case in which the STB  100  should support the passive standby mode as the standby mode; and 
     3) ‘2’ indicates a case in which the STB  100  should support the active standby mode in addition to the passive standby mode as the standby mode. 
     The service mode (service_mode) contains information for informing the external signaling descriptors which are provided by the high end of the broadcaster  200 . That is, the information contained in the service mode (service_mode) may refer to information on the background functions that may be performed by the STB  100  in the active standby mode. 
     The information contained in the service mode (service_mode) is illustrated in  FIG. 13 . When ‘F’ and ‘E’ are contained in the service mode (service_mode), the high end of the broadcaster  200  may provide the firmware update descriptor (fw_update_descriptor) and the EIT update descriptor (EIT_update_descriptor), and, when ‘E’, ‘A’, and ‘M’ are contained in the service mode (service_mode), the high end of the broadcast  200  may provide the EIT update descriptor (EIT_update_descriptor), the application update descriptor (app_update_descriptor), and the terminal management descriptor (terminal_management_descriptor). 
     On the other hand, ‘N’ in  FIG. 11  is a number of characters (‘F’, ‘E’, ‘A’, and ‘M’) contained in the service mode (service_mode) minus 1. For example, when ‘E’, ‘A’, and ‘M’ are contained in the service mode (service_mode), ‘N’ is “2” (=3−1). 
     5.3.2. Firmware Update Descriptor (fw Update Descriptor) 
       FIG. 14  illustrates a structure of the firmware update descriptor (fw_update_descriptor). The firmware update descriptor (fw_update_descriptor) is a descriptor that contains information on firmware update to be performed by the STB  100  in the active standby mode. 
     Specifically, as shown in  FIG. 14 , the firmware update descriptor (fw_update_descriptor) contains information on a descriptor tag (descriptor_tag), a descriptor length (descriptor_length), a start time (start_time), an effective duration (duration), and a free CA mode (free_CA_mode). 
     The descriptor tag (descriptor_tag) is a tag for identifying the firmware update descriptor (fw_update_descriptor), and is ‘0x81’ as shown in  FIG. 10 . 
     The descriptor length (descriptor_length) is information on a length of the firmware update descriptor (fw_update_descriptor). 
     The start time (start_time) contains information on a firmware update start time of the STB  100 , that is, information on a time at which the high end of the broadcaster  200  starts providing updated firmware to the STB  100 . A format of the start time (start_time) uses a combination of universal time, CO-ordinated (UTC) and modified Julian date (MJD). 
     The effective duration (duration)) contains information on a firmware update effective duration of the STB  100 , that is, information on a time during which the high end of the broadcaster  200  provides updated firmware to the STB  100 . The effective duration may be expressed by a code indicating hours, minutes, and seconds (for example, 01:45:30 is expressed by 0x014530). 
     The free CA mode (free_CA_mode) contains scramble information on the firmware. Specifically, ‘0’ is contained in the free CA mode (free_CA_mode) when the firmware is not scrambled, and ‘1’ is contained in the free CA mode (free_CA_mode) when the firmware is scrambled. 
     5.3.3. EIT Update Descriptor (EIT Update Descriptor) 
       FIG. 15  illustrates a structure of the EIT update descriptor (EIT_update_descriptor). The EIT update descriptor (EIT_update_descriptor) is a descriptor that contains information on EIT update to be performed by the STB  100  in the active standby mode. 
     Specifically, as shown in  FIG. 15 , the EIT update descriptor (EIT_update_descriptor) contains information on a descriptor tag (descriptor_tag), a descriptor length (descriptor_length), an EIT type (EIT_type), a last descriptor number (last_descriptor_number), a start time (start_time), an effective duration (duration), and a free CA mode (free_CA_mode). 
     The descriptor tag (descriptor_tag) is a tag for identifying the EIT update descriptor (EIT_update_descriptor), and is ‘0x82’ as shown in  FIG. 10 . 
     The descriptor length (descriptor_length) is information on a length of the EIT update descriptor (EIT_update_descriptor). 
     The EIT type (EIT_type) contains information on a type of EIT to be transmitted. Specifically, as shown in  FIG. 16 ,  1 ) when ‘1’ is contained in the EIT type (EIT_type), the type of the EIT is an EIT P/F, and, 2) when ‘0’ is contained in the EIT type (EIT_type), the type of the EIT is an EIT sch type. 
     The last descriptor number (last_descriptor_number) contains information on a version of the most recent EIT. 
     The start time (start_time) contains information on an EIT update start time of the STB  100 , that is, information on a time at which the high end of the broadcaster  200  starts providing an updated EIT to the STB  100 . A format of the start time (start_time) uses a combination of universal time, CO-ordinated (UTC) and modified Julian date (MJD). 
     The effective duration (duration) contains information on an EIT update effective duration of the STB  100 , that is, information on a time during which the high end of the broadcaster  200  provides an updated EIT to the STB  100 . The effective duration (duration) may be expressed by a code indicating hours, minutes, and seconds (for example, 01:45:30 is expressed by 0x014530). 
     The free CA mode (free_CA_mode) contains scramble information on the EIT. Specifically, ‘0’ is contained in the free CA mode (free_CA_mode) when the EIT is not scrambled, and ‘1’ is contained in the free CA mode (free_CA_mode) when the EIT is scrambled. 
     5.3.4. Application Update Descriptor (App Update Descriptor) 
     The application update descriptor (app_update_descriptor) is a descriptor that contains information on application update to be performed by the STB  100  in the active standby mode. 
     A descriptor tag (descriptor_tag) for identifying the application update descriptor (app_update_descriptor) is ‘0x83’ as shown in  FIG. 10 . 
     5.3.5. Terminal Management Descriptor (Terminal Management Descriptor) 
       FIG. 17  illustrates a structure of the terminal management descriptor (terminal_management_descriptor). The terminal management descriptor (terminal_management_descriptor) is a descriptor that contains information for managing the STB  100  in the active standby mode. 
     Specifically, as shown in  FIG. 17 , the terminal management descriptor (terminal_management_descriptor) contains information on a descriptor tag (descriptor_tag), a descriptor length (descriptor_length), a subscriber ID (subscriber_id), a reserved area (reserved), and private data (private_data_byte), and CRC. 
     The descriptor tag (descriptor_tag) is a tag for identifying the terminal management descriptor (terminal_management_descriptor), and is ‘0x84’ as shown in  FIG. 10 . 
     The descriptor length (descriptor_length) is information on a length of the terminal management descriptor (terminal_management_descriptor). 
     The subscriber ID (subscriber_id) is an ID for designating the STB  100 , which is a subscriber. 
     The private data (private_data_byte) is information necessary for managing the STB  100 , and a detailed content thereof is defined by the broadcaster. 
     The foregoing exemplary embodiments and advantages are merely exemplary and are not to be construed as limiting the present inventive concept. The exemplary embodiments can be readily applied to other types of apparatuses. Also, the description of the exemplary embodiments is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art.