KR20050028356A - Set-top-box and a broadcasting signal control method thereof - Google Patents

Abstract

A set top box and a method of controlling a broadcast signal in the set top box are provided to enable a main display to control the broadcast signal transmitted to a subordinate display, wherein the set top box includes a plurality of tuners and can receive many broadcast signals at the same time. A display distinction part(211) distinguishes a plurality of displays into a main display and a subordinate display. A reception part(213) receives a display instruction for displaying a broadcast signal transmitted to the subordinate display and a control signal for the displayed broadcast signal. When a control part(205) receives the display instruction, it displays the broadcast signal transmitted to the subordinate display in a PIP(Picture In Picture) manner When the control part receives the control signal, it performs one of a block of the broadcast signal, channel switch to another broadcast signal and transmission of a warning message in response to the received control signal.

Description

Set-top-box and a broadcasting signal control method

The present invention relates to a set top box, and more particularly, to a set top box having a plurality of tuners and capable of simultaneously receiving a plurality of broadcast signals, and a method for controlling a broadcast signal by the set top box.

Since the broadcast was officially broadcast, the TV for receiving the broadcast has been spreading faster than any other media and has produced a lot of broadcast contents.

In addition, it is true that the role of TV in the transmission of knowledge and information sharing can never be overlooked. However, in order to produce and transmit broadcasting programs, investment of certain facilities and capital was required at the same time, and this limitation was insufficient to catch up with the demands of various consumers.

As part of meeting these demands, an early cable television station needs specialized equipment with less investment than the existing over-the-air television station, and requires a separate device for watching cable TV in addition to the antenna for watching conventional TV. That's the Set-Top Box (STB).

The set-top box classified as the first generation made it possible to watch various cable TV channels, but could only serve as a unidirectional reception relay. In contrast, the digital set-top boxes classified as the second generation not only have a function of placing on a TV set, but their own roles become clearer like other home appliances, and various functions and additional services can be operated. . Digital set-top boxes are actually special computers that can send and receive data over the Internet. They also have protocols such as web browsers and TCP / IP.

Therefore, it is clear that set-top boxes will be the core of digital TV as much as the niche market until digital TV succeeds in commercialization and the price of TV receivers drops to the level at which mass distribution is possible.

1 is a block diagram schematically illustrating a typical set top box. Referring to the drawing, the set top box 100 includes a cable signal receiver 120, a storage unit 131, a controller 133, a graphics processor 135, and an interface unit 150. Here, the cable signal receiver 120, the controller 131, the storage 133, the graphics processor 135, and the interface 150 are connected to each other via the system bus 140.

Meanwhile, the cable signal receiver 120 includes a tuner 121, a demodulator 123, a demultiplexer 125, and a decoder 127. The interface unit 150 also includes a UART (Universal Asynchronous Receiver / Transmitter) 151 and a line driver / receiver 153.

The tuner 121 receives a video signal, an audio signal, data, etc. coming from a satellite, terrestrial wave, or a cable, and transmits the received video signal to the demodulator 123.

The demodulator 123 is responsible for sampling the analog signal and converting it into a digital bit stream. The Mpeg-2 stream is composed of PIDs (Packet IDs) and distinguished, and the demultiplexer 125 decompresses the audio signal, the video signal, and the data to the decoder 127 based on the PID. Here, in the case of a stream encrypted for commercial reasons (paid channel, etc.), a routine for decrypting and transmitting the password is required, and this role is played by a descriptor (not shown).

The decoder 127 decodes the video / audio signal from the demodulator 123 and the demultiplexer 125 into a signal that can be actually detected by the viewer, and outputs the decoded signal to a TV and / or a speaker.

The controller 131 plays a main role of controlling and managing each element in the set top box 100, such as a real-time operating system, a hard disk drive (HDD) (not shown), and a graphics processor 135. In addition, the controller 131 may be in charge of data processing parts such as a web service request and response, and an e-mail reception. Here, the real-time OS refers to software for driving and controlling each element of the set-top box and processing input and output with a viewer (operator).

The storage unit 133 is a storage such as operation data required for the operation of the control unit 131 and internal data to be temporarily stored, and more memory is required as a faster operation is required. Types of memory used in the set-top box 100 include a flash memory used for software upgrades, a temporary storage RAM, a kernel or an I / O system loaded with EEPROM.

The graphic processor 135 is in charge of graphic processing for overlaying the received data on a TV screen or displaying a web page on the TV screen.

Meanwhile, RS232C (Recommended Standard 232 Revision C), IDE (Integrated Drive Electronics), PCMCIA (Personal Computer Memory Card International Association), SCSI, to connect the set-top box 100 and external devices, or to exchange data between internal devices. (Small Computer System Interface), Infrared Data Association (IrDA), and Smart Card are provided.

Recently, as many homes have a plurality of display devices, users are required to simultaneously receive a plurality of digital broadcasts. However, in order to receive a plurality of digital broadcasts in one home, a plurality of set-top boxes must be provided, and the addition of set-top boxes causes a considerable cost burden.

Accordingly, a new concept set-top box has been developed to meet the needs of users who want to simultaneously receive a plurality of digital broadcasts and to prevent the problem of additional cost of the set-top box. One such set top box of the new concept is a set top box with a plurality of tuners. A set top box with multiple tuners has a plurality of tuners in one set top box, and the cost of adding a set top box by allowing a user to watch different broadcasts through a plurality of displays connected to each tuner. It is possible to meet the needs of users who want to simultaneously receive multiple digital broadcasts without burden.

However, when receiving different broadcast signals through displays installed in different spaces, there is a need to monitor broadcast signals displayed on displays installed in different spaces on one display. In particular, in times of harmful sites and broadcasting floods, it is more necessary for parents to monitor broadcast signals transmitted to displays installed in their children's rooms. It may be necessary to block or switch to another broadcast channel.

The present invention has been made in accordance with the needs as described above, in the set-top box having a plurality of tuners that can receive a plurality of broadcast signals at the same time, the set-top that can control the broadcast signal transmitted from the main display to the sub-display An object of the present invention is to provide a box and a method of controlling the broadcast signal.

According to an aspect of the present invention, a set-top box includes a plurality of tuners and transmits a broadcast signal received through the plurality of tuners to each corresponding display, wherein the set-top box includes: A display identification unit for identifying the set one as a main display and the other as a sub display, a display command for displaying a broadcast signal transmitted to the subdisplay, and a receiving unit for receiving a control signal for the displayed broadcast signal, and the display command When received, the broadcast signal transmitted to the subdisplay is displayed on the main display as picture in picture (PIP), and when the control signal is received, the broadcast signal transmitted to the subdisplay in response to the received control signal is received. Block, switch channel to other broadcast signal, and send warning message It characterized in that it comprises a control unit for performing any of them.

Preferably, the set top box includes an OSD for providing a selection menu to allow a user to select one of blocking the broadcast signal transmitted to the sub-display, switching a channel to another broadcast signal, and transmitting a warning message. On Screen Display) is further included.

Preferably, the set top box further includes a sub-display selecting unit that selects at least one of the plurality of sub-displays, and the control unit is configured to receive the broadcast signal transmitted to the sub-display selected by the sub-display selecting unit. It is displayed on the main display. Here, when the blocking of the broadcast signal is selected from the selection menu provided by the OSD unit, the controller may block the broadcast signal transmitted to the subdisplay to turn off the display.

In addition, when the channel switching is selected from the selection menu provided by the OSD unit, it is preferable to switch the channel of the broadcast signal transmitted to the sub display to a channel of another broadcast signal.

Preferably, the set top box further includes a sub-display channel selector for selecting a channel for switching the channel of the broadcast signal transmitted to the sub-display to a channel of another broadcast signal.

Preferably, the set-top box further includes a warning message storage unit for storing the warning message in various forms, and if the transmission of the warning message is selected from the selection menu provided by the OSD unit, the control unit stores the warning message. The selected warning message among the various types of warning messages stored in the unit is transmitted to the subdisplay.

The set top box may further include a warning message selecting unit for selecting any one of the various types of warning messages stored in the warning message storage unit, and the controller may include the warning messages of various types stored in the warning message storage unit. Preferably, the main message is displayed and the warning message selected by the warning message selecting unit is displayed on the sub display.

On the other hand, the set-top box according to the present invention, (a) identifying one of the plurality of displays connected to the set-top box as the main display, the rest as a sub-display, (b) displays the broadcast signal transmitted to the sub-display Receiving a display command for the display, (c) When the display command is received, displaying the broadcast signal transmitted to the sub display on the main display in the PIP, (d) Control signal for the displayed broadcast signal And (e) when the control signal is received, one of interruption of the broadcast signal transmitted to the subdisplay, channel switching to another broadcast signal, and warning message transmission in response to the received control signal. It provides a broadcast signal control method comprising the step of performing.

Preferably, the broadcast signal control method of the set-top box, (f) the user can select any one of the blocking of the broadcast signal transmitted to the sub-display, the channel switching to another broadcast signal, and the transmission of warning messages. Providing a selection menu to further include.

Preferably, the method for controlling a broadcast signal of the set-top box further includes (g) selecting at least one of the plurality of subdisplays, wherein step (e) comprises selecting the subdisplays selected by the subdisplay selection unit. The broadcast signal transmitted to the main display is displayed.

Here, when the blocking of the broadcast signal is selected from the selection menu provided by step (f), the control unit preferably blocks the broadcast signal transmitted to the sub-display to turn off the display.

In addition, when the channel switching is selected from the selection menu provided by step (f), it is preferable to switch the channel of the broadcast signal transmitted to the sub display to a channel of another broadcast signal.

Preferably, the method for controlling a broadcast signal of the set top box further includes (h) selecting a channel for converting a channel of the broadcast signal transmitted to the subdisplay into a channel of another broadcast signal.

Preferably, the method for controlling a broadcast signal of the set top box further comprises the step of (i) storing the warning message in various forms, wherein the warning message transmission is selected from the selection menu provided by step (f). In step (e), the warning message selected from the warning messages of various types stored in the warning message storage unit is transmitted to the sub display.

In addition, the broadcast signal control method of the set-top box further includes the step of (j) selecting any one of the various types of the warning message stored in the warning message storage unit, the step (e) is the warning message storage unit Preferably, the stored warning messages are displayed on the main display, and the warning messages selected by the warning message selection unit are displayed on the subdisplay.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

Figure 2 is a block diagram schematically showing a set top box according to the present invention. Referring to the drawings, the set-top box 200 includes a tuner 1 201, tuner 2 203, a control unit 205, a first image output unit 207, a second image output unit 209, and a display identification unit ( 211, a receiver 213, an OSD unit 215, a sub display selector 217, a channel switcher 219, an alert message storage 221, and an alert message selector 223. Here, the first image output unit 207 and the second image output unit 209 are connected to the first display 230 and the second display 240, respectively. Although the set top box 200 is illustrated as having two tuners 201 and 203 in the drawing, the present invention is not limited thereto and may be implemented to include a plurality of tuners. In addition, in order to simplify the description, components that perform the general functions of the set-top box 200 are omitted.

The tuner 1 201 and the tuner 2 203 each receive a selection signal from a channel selector (not shown) provided to allow a user to select at least one of various broadcast channels, and correspond to the received selection signal. Receives a broadcast signal from a broadcast channel. Here, the channel selector is preferably provided in each of the displays 230 and 240 or in a remote controller (not shown) disposed around each of the displays 230 and 240. In this case, when the channel selector is provided in a remote controller disposed around each of the displays 230 and 240, the tuners 201 or 203 corresponding to the infrared signals received from the remote controller by the respective displays 230 and 240 are used. In this case, the broadcast signal is preferably received by the tuners 201 and 203. Tuner 1 201 and tuner 2 203 convert the received broadcast signal into an intermediate frequency (IF) signal.

The controller 205 transmits the intermediate frequency signal converted by the tuner 1 201 and the tuner 2 203 to the first image output unit 207 and the second image output unit 209, respectively. The first image output unit 207 and the second image output unit 209 process the received intermediate frequency signals by image signals, and display them on the respective displays 230 and 240. Here, the image signal processing performed by the first image output unit 207 and the second image output unit 209 includes sampling of the received intermediate frequency signal, conversion to a digital bitstream, and decoding processing.

The display identification unit 211 identifies one set of the plurality of displays 230 and 240 as the main display and the other as the sub display. In order to facilitate identification, it is preferable to set the first display 230 connected to the first terminal (not shown) as the main display and the display connected to the remaining terminals as the sub display. Since only two displays 230 and 240 are connected in the drawing, the first display 230 is set as the main display and the second display 240 is set as the sub display.

The receiver 213 receives a display command for displaying a broadcast signal transmitted to the sub display 240 and a control signal for the broadcast signal displayed on the sub display 240. Here, the receiver 213 may be implemented to receive an infrared signal corresponding to a display command or a control signal from a remote controller (not shown) that sends a control command to the set top box 200. However, the reception of the display command or the control signal by the receiving unit 213 is not limited to that by the remote controller, and a separate input terminal (not shown) is provided in the set-top box 200, and the display command from the installed input terminal. Or it may be implemented to receive a control signal.

In this case, when the receiver 213 receives the display command, the controller 205 is implemented to display the broadcast signal transmitted to the sub display 240 on the main display 230 as a picture in picture (PIP). Here, the PIP means a function capable of simultaneously displaying a small screen separately from the screen viewed from the screen of the television receiver. This is similar to the window of a personal computer (PC), and the side which becomes the background on the screen of a television receiver is called PIP.

In addition, when the receiving unit 213 receives the control signal, the control unit 205 blocks the broadcast signal transmitted to the sub display 240, the channel switching to another broadcast signal, and the warning message transmission in response to the control signal. Is implemented to do one.

The OSD unit 215 displays a selection menu on the main display 230 so that the user can select any one of blocking the broadcast signal transmitted to the sub display 240, switching a channel to another broadcast signal, and transmitting a warning message. to provide. When the selection menu is provided on the main display 230 by the OSD unit 215, the user may access a selection key (not shown) provided on the main display 230 or a remote controller disposed around the main display 230. One of the selection menus can be selected through the provided selection key.

Here, when blocking of the broadcast signal is selected from the selection menu provided to the OSD unit 215, the controller 205 may block the broadcast signal transmitted to the sub display 240 to turn off the sub display 240. In addition, when a channel switching to another broadcast signal is selected among the selection menus provided to the OSD unit 215, the controller 205 switches the channel of the broadcast signal transmitted to the sub display 240 to the channel of the other broadcast signal. desirable. In this case, the set top box 200 preferably includes a channel switching unit 219 to switch the channel of the broadcast signal transmitted to the sub display 240 in the set top box 200. Although the channel switching unit 219 is illustrated as being installed in the set top box 200, the present invention is not limited thereto, and the channel switching unit 219 is controlled by an infrared signal to the set top box 200 around the set top box 200. An infrared remote controller (not shown) for transmitting a command may be provided, and a remote controller (not shown) for transmitting a control command with an infrared signal to the main display 230 may be provided around the main display 230. It may be.

Although the drawings show that two displays 230 and 240 are connected to the set top box 200, when the set top box 200 includes three or more tuners and three or more displays are connected to the set top box 200, the set top box 200 includes a plurality of displays. Preferably, the sub display selector 217 selects at least one of the sub displays. When the sub display selection unit 217 selects any one of the plurality of sub displays, the control unit 205 transmits a broadcast signal transmitted to the sub display 240 selected by the sub display selection unit 217 to the main display 230. PIP is displayed on the screen.

The warning message storage unit 221 stores warning messages of various types. Examples of warning messages stored in the warning message storage unit 221 include "Stop watching TV, study", "This is not a program that kids watch. Turn the channel", "It's time to sleep. Turn off the TV." have. Various types of warning messages stored in the warning message storage unit 221 may be displayed on the main display 230 so that any one warning message can be selected by the user.

When the warning message is displayed on the main display 230, the user selects any one warning message through the warning message selecting unit 223. Here, the warning message selector 223 is described as being provided in the set-top box 200, but the warning message selector 223 may be provided on the main display 230 and is disposed around the main display 230. It may be provided in the remote controller.

When any one warning message is selected by the warning message selecting unit 223, the control unit 205 may display the warning message selected by the user among various types of warning messages stored in the warning message storage unit 221. Mark it.

3 is a flowchart illustrating a broadcast signal control method using a set top box according to the present invention. Referring to the drawings, the display identification unit 211 receives a broadcast signal processed by the first image output unit 207 and the second image output unit 209, and outputs the received broadcast signal to each image output. It transmits to the display 230,240 corresponding to the part 207,209. In this case, the display identification unit 211 identifies one set of the plurality of displays 230 and 240 as the main display and the other as the sub display (S301). The identification of the main display and the sub display by the display identification unit 211 is preferably set in the production process of the product. In addition, the identification of the main display and the sub display by the display identification unit 211 serves as a main display using the first display 230 connected to the first terminal, and the display connected to the remaining terminals to be easily recognized by the user. It is preferably set to identify with the display. In the drawing, since the two displays 230 and 240 are connected to the set top box 200, the first display 230 is set as the main display and the second display 240 is set as the sub display.

The sub display selecting unit 217 selects at least one of the plurality of sub displays except the main display from among the plurality of displays connected to the set top box 200 (S303). However, when two displays are connected to the set top box 200 as shown in the drawing, the sub display selection unit 217 may be omitted since one is set as the main display 230 and the other is the sub display 240. have.

The receiver 213 receives a display command for displaying a broadcast signal transmitted to the selected sub display 240 (S305). When a display command for the broadcast signal transmitted to the sub display 240 selected by the receiver 213 is received, the controller 205 receives the broadcast signal transmitted to the display selected by the sub display selector 217 as the main display ( The display on the screen 230 is PIP (S307). In this case, the ratio of the size of the mother screen of the main display 230 and the size of the PIP screen is preferably about 4: 1. However, the size of the PIP screen is not limited thereto, and may be implemented to be arbitrarily changed. Here, the receiving unit 213 receives a display command of a user input through an input terminal installed in the set-top box 200 or displays a display command through a remote controller disposed around the set-top box 200 and transmitting an infrared signal. Can be received. In addition, the receiver 213 may be implemented to receive a display command from the sub display selector 217 simultaneously with the selection of the sub display by the sub display selector 217.

The OSD unit 215 provides the main display 230 with a selection menu for the broadcast signal transmitted to the sub display 240 selected by the sub display selecting unit 217 (S309). Here, the selection menu refers to a list of menus provided to allow the user to select any one of blocking of a broadcast signal transmitted to the sub display 240, switching a channel to another broadcast signal, and transmitting a warning message.

The user of the main display 230 may select one of the selection menus provided by the OSD unit 215. In this case, the selection of any one of the selection menus provided by the OSD unit 215 may be performed through a remote controller disposed around the main display 230, and may be performed through an input terminal installed in the main display 230. May be In addition, it may be performed through an input terminal installed in the set-top box 200, it may be implemented by sending an infrared signal directly to the set-top box 200 through a remote controller.

The receiving unit 213 receives a signal for selecting one of the selection menus provided by the OSD unit 215 as a control signal (S311). The control signal received by the receiver 213 is transmitted to the controller 205.

If the control signal transmitted from the receiver 213 is a channel switch signal (S313), the controller 205 receives the channel signal selected through the channel switch unit 219 (S315). At this time, the channel switching unit 219 is preferably implemented so that when the user selects a channel switching menu from the selection menu provided by the OSD unit 215, a channel of another broadcast signal to be switched at the same time.

When the channel signal is received from the channel switcher 219, the controller 205 switches the channel of the broadcast signal transmitted to the sub display 240 to the channel of the broadcast signal received by the channel switcher 219 (S317). ).

If the control signal transmitted from the receiving unit 213 is a warning message transmission signal (S319), the control unit 205 displays a list of various types of warning messages stored in the warning message storage unit 221 on the main display 230 ( S321). When the warning message list of various types is displayed on the main display 230, the user selects one of the warning messages of the various types through the warning message selecting unit 223 (S323).

When any one warning message is selected by the warning message selecting unit 223, the controller 205 displays the selected warning message on the sub display 240 selected by the sub display selecting unit 217 (S325).

If the control signal transmitted from the receiver 213 is not a channel switching signal or a warning message transmission signal, the controller 205 blocks the broadcast signal transmitted from the received control signal to the sub display 240 (S327). . That is, the controller 205 cuts off the broadcast signal transmitted to the sub display 240 selected by the sub display selector 217 to turn off the power of the sub display 240 (S329). Here, when the control signal transmitted from the receiving unit 213 is neither a channel switching signal nor a warning message transmission signal, the control unit 205 uses the received control signal as a cutoff signal of the broadcast signal transmitted to the sub display 240. Although described as a judgment, it is not limited to this.

That is, the controller 205 determines whether the control signal transmitted from the receiver 213 is a cutoff signal of the broadcast signal, and if the received control signal is a cutoff signal of the broadcast signal, cuts off the broadcast signal. When the received control signal is not a blocking signal of the broadcast signal, the control signal may be implemented to maintain the broadcast signal transmitted to the sub display 240 selected by the sub display selector 217.

Thus, the set-top box according to the present invention can monitor the sub-display on the main display even when watching various broadcast signals at the same time through a plurality of displays connected to the set-top box, it is possible to properly block the broadcast program harmful to the youth.

According to the present invention, by monitoring the broadcast signal transmitted from the main display to the sub-display of the plurality of displays connected to the set-top box, it is possible to perform appropriate measures for the broadcast program harmful to the youth.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the present invention is not limited to the specific embodiments of the present invention without departing from the spirit of the present invention as claimed in the claims. Anyone skilled in the art can make various modifications, as well as such modifications are within the scope of the claims.

1 is a block diagram schematically showing a typical set top box,

2 is a block diagram schematically showing a set top box according to the present invention; and

3 is a flowchart illustrating a broadcast signal control method using a set top box according to the present invention.

Explanation of symbols on the main parts of the drawings

201, 203: tuner 205: control unit

207, 209: video output unit 211: display identification unit

213: receiver 215: OSD unit

217: sub display selection unit 219: channel switching unit

221: warning message storage unit 223: warning message selection unit

Claims (16)

A set top box having a plurality of tuners and transmitting the broadcast signals received through the plurality of tuners to respective corresponding displays, A display identification unit for identifying one of a plurality of the displays as a main display and a remaining subdisplay; A receiving unit for receiving a display command for displaying a broadcast signal transmitted to the sub display and a control signal for the displayed broadcast signal; And When the display command is received, the broadcast signal transmitted to the subdisplay is displayed on the main display as picture in picture (PIP), and when the control signal is received, the broadcast signal is transmitted to the subdisplay in response to the received control signal. And a control unit for performing any one of blocking the broadcast signal, switching a channel to another broadcast signal, and transmitting a warning message. The method of claim 1, An OSD (On Screen Display) unit providing a selection menu to the main display to allow a user to select one of blocking the broadcast signal transmitted to the sub display, switching a channel to another broadcast signal, and transmitting a warning message. Set top box characterized in that it further comprises. The method of claim 2, Further comprising: a sub-display selection unit for selecting at least one of the plurality of sub-display, And the control unit displays the broadcast signal transmitted to the sub display selected by the sub display selection unit on the main display. The method of claim 2, And if the blocking of the broadcast signal is selected among the selection menus provided by the OSD unit, the control unit turns off the display by blocking the broadcast signal transmitted to the subdisplay. The method of claim 2, And when the channel switching is selected from the selection menu provided by the OSD unit, converting the channel of the broadcast signal transmitted to the sub display into a channel of another broadcast signal. The method of claim 5, And a channel switching unit for converting a channel of the broadcast signal transmitted to the sub display into a channel of another broadcast signal. The method of claim 2, Further comprising: a warning message storage unit for storing the warning message in various forms, If the transmission of the warning message is selected from the selection menu provided by the OSD unit, the control unit transmits the selected warning message of the various types of warning messages stored in the warning message storage unit to the sub display. Set top box. The method of claim 7, wherein And a warning message selecting unit for selecting any one of the warning messages in various forms stored in the warning message storage unit. The control unit may display the warning messages of various types stored in the warning message storage unit on the main display, and display the warning message selected by the warning message selecting unit on the sub display. (a) identifying one of the plurality of displays connected to the set top box as the main display and the other as the subdisplay; (b) receiving a display command for displaying a broadcast signal transmitted to the subdisplay; (c) if the display command is received, displaying the broadcast signal transmitted to the subdisplay on the main display as a PIP; (d) receiving a control signal for the displayed broadcast signal; And (e) when the control signal is received, performing any one of blocking the broadcast signal transmitted to the sub display, switching a channel to another broadcast signal, and transmitting a warning message in response to the received control signal; Broadcast signal control method of a set-top box comprising a. The method of claim 9, (f) providing a selection menu to allow a user to select any one of blocking the broadcast signal transmitted to the subdisplay, switching a channel to another broadcast signal, and transmitting a warning message. Broadcasting signal control method of a set-top box. The method of claim 10, (g) selecting at least one of the plurality of subdisplays; In the step (e), the broadcast signal control method of the set top box, characterized in that for displaying the broadcast signal transmitted to the sub-display selected by the sub-display selection unit on the main display. The method of claim 10, If the blocking of the broadcast signal is selected from the selection menu provided by step (f), the control unit turns off the display by blocking the broadcast signal transmitted to the subdisplay. Control method. The method of claim 10, If the channel switching is selected from the selection menu provided by step (f), converting a channel of the broadcast signal transmitted to the sub display into a channel of another broadcast signal. . The method of claim 13, and (h) selecting a channel for switching the channel of the broadcast signal transmitted to the sub display to a channel of another broadcast signal. The method of claim 10, (i) storing the warning message in various forms; If the warning message transmission is selected from the selection menu provided by the step (f), the step (e) is a set-top box, characterized in that for transmitting the selected warning message of the stored warning message of the various forms to the sub-display Broadcast signal control method of the. The method of claim 15, (j) selecting any one of the various types of warning messages stored in the warning message storage unit; In the step (e), the warning message of various forms stored in the warning message storage unit is displayed on the main display, and the warning message selected by the warning message selecting unit is displayed on the sub display. Method of controlling broadcast signal of box.