JPH03201782A - Catv system - Google Patents

Abstract

PURPOSE:To allow a center side to quickly cope with the address switching operation for illegal use by sending an address switching operation signal to the center equipment and confirming the illegal use on an alarm display when a terminal equipment applies switching operation to an address switch for the illegal use. CONSTITUTION:A terminal equipment 14 is provided with a means sending the state of address switches 16, 18 subject to switching operation to a polling of a center equipment 10 without setting change of sender's own address when the switching operation of the address switches 16, 18 is implemented and with a means applying setting change to sender's own address to the state of the address switches 16, 18 subject to switching operation after lapse of a prescribed time. Then even when the terminal equipment 14 applies switching operation to the address switches 16, 18 for illegal use, the setting change of sender's own address is not immediately implemented and the switching state of the address switches 16, 18 is returned to the polling from the center equipment 10 to confirm the switching. Thus, illegal use is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention enables a center device to poll a terminal device and send back response information, and when a correct response is obtained, control such as descrambling can be performed. Regarding CATV system.

[Prior Art] Conventionally, in a CATV system having a two-way transmission function, a center device repeatedly polls a large number of terminal devices one after another, and the terminal devices preset the calling address and address switch by the center polling. If the terminal determines that it matches the terminal's own address, it returns response information in which the terminal's own address and data are combined, and the center device decodes the terminal response data and performs the necessary processing.

In such a CATV system, among the large number of subscribers,
A descrambling code is sent only in response to a request from a subscriber who has registered after receiving an application so that they can watch paid programs, and the terminal address is The program checks whether or not you are a pre-registered paying viewer, and only if you are, a descrambling code is sent so that you can watch the video.

[Problems to be Solved by the Invention] However, in such a conventional CATV system, only a request from a subscriber terminal registered in a center device among a large number of subscriber terminals is scrambled. Since the release data was sent to enable viewing of paid broadcast programs, if the address switch of the terminal device was changed for unauthorized use and the setting was changed to another registered terminal address, unauthorized paid viewing could be performed. There was a problem with the program being viewed.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a CATV system that can reliably prevent unauthorized use due to address setting changes.

[Means for Solving the Problem] First, the present invention connects a plurality of terminal devices 14 to a coaxial transmission line 12 from a center device 10, repeatedly polls the plurality of terminal devices 14 from the center device 10 in turn, and On the other hand, the present invention is directed to a CATV system in which desired data is returned to the center device 10 together with the own address when the terminal device 14 determines that a received address (polling address) matches its own set address. In addition, the reference numerals in the drawings of the embodiments are also shown.

In the present invention, for such a CATV system,
In the terminal bag [14], the address switch (16, 18)
means for transmitting the state of the address switch (16, 18) that has been switched in response to polling of the center device 10 without changing the setting of the address switch (16, 18) when the switching operation is performed; ) is provided for changing the setting of the own address to the state of the operated address switch (16, 18) after a certain period of time longer than the switching operation of the address switch can be confirmed in the center device 10 after the switching operation of the address switch (16, 18).

Further, when the center device 10 determines that the address switch has been switched based on the information sent from the terminal device 14, an abnormality is displayed and a control signal is sent to the terminal device whose address switch has been switched, disabling its use. A means for transmitting the address is provided, and the terminal device is forcibly disabled from use before the setting of its own address is changed after a certain period of time.

[Function] In the CATV system of the present invention having such a configuration, even if the address switch is operated on the terminal device for unauthorized use, the setting of the own address is not immediately changed, and the setting of the own address is not changed immediately. The switching state of the address switch can be returned in response to polling to confirm that the address switch has been switched.

In addition, since the self-address is set to change to the state of the address switch that was switched after a sufficient period of time has passed for the center to confirm the switching, the center device sends a control signal indicating that it cannot be used. It is possible to forcibly turn off the power to the terminal device to prevent unauthorized use.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention.

In FIG. 1, 10 is a center device;
A coaxial transmission line 12 is pulled out from 10, and a coaxial transmission line 1
2, bidirectional amplifiers 20 are provided at predetermined intervals. Further, a tap-off 22 is connected to the coaxial transmission line 12,
A terminal device 14 is connected to a branch terminal of the tap-off 22. Although one terminal device 14 is shown in FIG. 1, in reality, a plurality of terminal devices are connected via the tap-off 22.

The terminal device 14 has a mixing/distributing device 26 following the input terminal 24, and has a downstream frequency band of 70 to 450 MHz on the distribution terminal side.
A bandpass filter 28 is provided, and the signal from the bandpass filter 28 is demodulated by a tuner 30 and converted into a video IF signal and an audio IF signal, which are output to a video detection circuit 32 and an audio detection circuit 34, respectively. . A descrambler 36 is provided following the video detection circuit 32, and scrambling processing is performed on the center device 10 side for specific channels broadcasting pay programs, and if the descrambler 36 is not in an operating state. Video output terminal 3
It is not possible to view the video signal from 8, and the center device side 1
The descrambling process is performed only in the operating state of the descrambler 36 upon reception of the descrambling code from 0, and a video signal can be obtained from the video output terminal 38.

On the other hand, a modem 42 is connected to the branch terminal side of the branch 26 to enable data transmission with the center device 10.

The modem 42 is composed of a demodulator and a modulator. The demodulation section demodulates the high frequency signal sent by FSK-FM modulation of polling data using an available upstream channel of 70 to 450 MHz, and outputs received data. Further, the modulator uses a predetermined channel within the 10-50 MHz band in the downstream direction to send out an FSX-FM modulated signal based on response data from the terminal to the coaxial transmission line 12.

Modem 42 is connected to CPU 46 via bus 44. For bus 44 from CPU 46, l1048,
A ROM 50 storing a control program, a RAM 52 storing a self-address, an address setting switch 16, an address setting possible display lamp 54, and an address number switch 18 are connected. Further, a battery 56 is connected to the RAM 52 in which the self-address is stored and registered, so that the self-address in the RAM 52 can be retained even if the terminal device 14 is powered off. Furthermore, a descrambling request switch 80 is provided for requesting the center device 10 to view a pay program.

FIG. 2 is a block diagram of an embodiment of the center device 10 shown in FIG. 1.

In FIG. 2, the center device 10 is provided with a CPU 60, and a display device 64. R.O.
M66, RAM68. Speech synthesis output device 70. An automatic dialing device 72 is connected. Here, the terminal address of a subscriber who has applied to view a pay program is registered in advance in the RAM 68.

On the other hand, on the coaxial transmission line 12 side of the CPU 60, there is a communication unit 74. A modem 76 and a mixer 78 are provided.

The CPU 60 performs polling control by sequentially and repeatedly calling a plurality of terminal devices, and the polling data for this polling is the terminal address.

It consists of 3 bytes: command data and BCC (block check code). The communication unit 74 is the CPU 60
When receiving a polling command from the controller, it creates a 3-byte polling data format and outputs it to the RF modulator 761 of the modem 76. The RF modulator 761 performs FSX modulation using frequencies fl and f2 corresponding to bit 0°1 of the polling data, and further performs FM modulation on vacant channels in the 70 to 450 MHz downlink range, and transmits it to the coaxial transmission line 12 via the mixer 78. Send to. On the other hand, the received high frequency signal from the terminal obtained by the mixer 78 is demodulated by the RF demodulator 76-2 and provided to the communication unit 74 as terminal response data. The received data output from this RF demodulator 76-2 also consists of 3 bytes of terminal address, command data, and BCC, and the communication unit 74 performs a parity check based on the BCC, and if the data is correct, the terminal address and command Output the data to the CPU 60.

The CPU 60 decodes the terminal response data, and if it is a request to view a paid program, searches the RAM 68 for the terminal address of the registered subscriber who has applied to view the paid program, and if a registered address matching the requested terminal address is obtained, the CPU 60 decodes the terminal response data. By including the descrambling code in the command data and transmitting it during the next polling, the terminal device 1 shown in FIG.
The descrambler 36 is put into operation via the l1048 of No. 4 to create a state in which pay programs can be viewed.

In the CATV system shown in FIGS. 1 and 2, according to the present invention, the terminal equipment RI 114 shown in FIG. 1 is provided with the following two functions.

That is, the address number switch 18 in the terminal device 14
If an address switching operation is performed in which the address setting switch 16 is turned on in this state by changing the address number to an address number different from the own address of the RAM, the CPU 46
It has a function of transmitting the state of the switched address number switch 18 in response to polling from the center device 10 without changing the self address of the AM 52 to the state of the switched address number switch 18.

Another function is to start a timer when an address switching operation is performed by operating the address number switch 18 and address setting switch 16, and when the terminal address switching operation is performed in the center device 10 set in the timer. After a certain period of time has elapsed, the RAM5
This is a function to switch the self-address of No. 2 to the setting state of the address number switch 18. After this address switching operation is performed, the time longer than the time required for the center device 10 to confirm the address switching operation in order to actually change the setting of the self-address in the RAM 52 means that the center device 10 transmits the address switching operation by polling. However, it is determined as the time required for the center device 10 to transmit a control code indicating that it cannot be used to the terminal device 14 at the next polling, and forcibly turn off the power of the program reception system. Specifically, it is sufficient to set the time for at least two to three polling cycles.

In response to the control function accompanying the address switching operation in the terminal device 14, the CPU 60 of the center device 10 shown in FIG. A function is provided to display an abnormality on the device 64. Further C
The PU 60 has a function of displaying an abnormality on the display device 64 and transmitting a control signal disabling the terminal device for which the address switching operation has been performed, that is, a disabling control code, in the next polling command data. provided.

Next, the operation of the terminal device 14 shown in FIG. 1 will be explained with reference to the operation flow diagram of FIG. 3.

In FIG. 3, when the terminal device 14 is first powered on, it is checked in step 31 (hereinafter "step" will be omitted) whether or not there is address data in the RAM 52. If there is no address data, proceed to S2, turn on the addressable display lamp 54 to prompt address setting,
When it is determined in S3 that the address setting switch 16 has been turned on with the address number switch 18 set to the preset terminal address, the process proceeds to S4 and the address data determined by the address number switch 18 is registered in the RAM 52 as the own address. do. Of course, RAM 5 is stored in advance in Sl.
If the own address is registered in 2, the process directly advances to S5 without performing the processes from 82 to S4.

In S5, it is determined whether or not polling data has been received from the center device 10. When polling data is received, the process proceeds to 86 and it is determined whether or not the received address (polling address) matches the own address in the RAM 52. If they do not match, the process returns to S5, and if they do match, it is determined that the call is its own and the process proceeds to S7. In S7, it is determined whether or not the received polling command data includes an unusable control code, and if there is no unusable control code, the process goes to S9.
Then, it is determined whether or not the self address registered in the RAM 52 and the address of the address number switch 18 match. That is, it is determined whether an address switching operation has been performed. If the RAM address and the switch address match in S9, it is assumed that no address switching operation has been performed, and the process proceeds to transmission processing.

On the other hand, if the address setting switch 16 is operated after the address number switch 18 has been changed due to unauthorized use, the RAM address and the switch address do not match in S9. In this case, the process advances to S10 and the center
The switch address of the switched address number switch 18 is set to the terminal address (sending address) in the response data format for 0. Of course, S1
0 may be set by setting the switch address in the command data following the terminal address without changing the terminal address in the response format.

Next, start the timer with Sll. As described above, this timer times out when a certain period of time has elapsed that is longer than the address switching operation can be confirmed by the center device 10.

Next, it is checked whether or not the timer started at Sl2 has timed up, and since the timer has not timed up in the initial state, the process moves to transmission processing, and at step 310, response data is sent with the switch address of the address number switch 18 set as the transmission address. is sent back to the center device 10.

On the other hand, if it is determined in S12 that a time-up has occurred after a certain period of time has passed since the address switching operation, the process proceeds to S13 and the RAM 5 is
An address setting change is performed in which the self address of No. 2 is rewritten to the switch address of the address number switch 18 which has been switched.

Although the operation flow in FIG. 3 shows the Sll timer start, S12 time-up, and S13 RAM address data rewriting as a continuous routine,
In the actual sequence, Sll-S13 is provided as a subroutine, and monitors time-up independently of the data transmission/reception processing in the main routine of the terminal device.
The data is set to the switch data of the address number switch 18.

FIG. 4 is an operation flow diagram of the center device 10 shown in FIG. 2.

In FIG. 4, terminal polling is first performed on Sl,
In the next step 82, reception of terminal response data is checked.

When the terminal response data is received, the process proceeds to 83, where it is determined whether or not the polling address matches the received address.If no address switching operation has been performed on the terminal side, since both addresses match, the process proceeds to 84, where the received data is checked. A reception process based on decoding is performed, the polling address is incremented in S5, and the process proceeds to Sl terminal polling again.

On the other hand, if the polling address and the receiving address do not match in S3, it means that an address switching operation has been performed on the terminal side, and in this case, the process advances to S6 where an error is displayed and an address switching operation is performed. A disabling control code is added to the next polling data of the terminal that has been received, and the process proceeds to reception processing in S4. Of course, even if the process advances to S4, since the address switching operation is still being performed, no processing is performed based on the received data.

When the unusable control code is set in S6 when the terminal address switching operation is determined in S3 shown in FIG. 4, the second polling after the address switching operation is determined and the process proceeds to 87 in FIG. An unusable control code is determined, and in this case, the process proceeds to S8, where the unusable control is performed, specifically, the bandpass filter 28. in the terminal control device 14 shown in FIG. Tuner 30. Video detection circuit 32
゜The power to the audio detection circuit 34 and descrambler 36 is cut off to forcibly prevent the terminal device 14 from viewing the program. Of course, the timer started in S11 is also reset due to the unusable control, and since time-up is not determined in S12, the process does not proceed to 313 and rewrite the RAM address data.
The self-address of the RAM 52 is still maintained as the initially set correct address data.

If you wish to change the setting of the terminal address as necessary and not for unauthorized use, if you stop the transmission function of the unusable control code in the center device 10, you can change the setting of the terminal address by operating the address number switch 18 and the address setting switch 16.
The self-address of AM52 can be changed.

[Effects of the Invention] As explained above, according to the present invention, even if the address switch is operated on the terminal device for unauthorized use such as viewing paid programs, the setting of the own address is not immediately changed, and the center By transmitting an address switching operation to the device and having it confirmed by displaying an alarm, the center can quickly respond to address switching operations for unauthorized use.

In addition, after a sufficient period of time has elapsed for the center to confirm the address switching, the self-address can be changed to the state of the address switch operated on the terminal. It is also possible to forcefully turn off the power of the terminal device by sending it to prevent unauthorized use.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention; FIG. 2 is a block diagram of an embodiment of a center device of the present invention; FIG. 3 is an operation flow diagram of a terminal device of the present invention; FIG. 4 is a block diagram of a center device of the present invention FIG. 2 is an operation flow diagram. In the figure, 10: Center device 12: Coaxial transmission line 14: Terminal device 16: Address setting switch 18 Near address number switch 20: Bidirectional amplifier 22: ; Tap off 24: Input terminal 26: Branch 28: Bandpass filter 30: Tuner 42: Video detection circuit 34: Audio detection circuit 36: Descrambler 38: Video output terminal 40: Audio output terminal 42; 76: Modem 44. 62: Bus 46. 60: CPU 48: 110 50. 66: ROM 52, 68: RAM 54 Near address setting display lamp 56: Battery 64: Display device 70: Voice synthesis output device 72: Automatic dial device 74: Communication unit 76-1: RF modulation section 76-2: RF demodulation Part 78: Mixer

Claims (1)

[Claims] 1. A plurality of terminal devices are connected to a coaxial transmission line from a center device, and the center device repeatedly polls the plurality of terminal devices one after another, and in response to the polling, the terminal device sets the receiving address and its own settings. In a CATV system that adds a self-address to a center device when determining a match with an address and returns desired data, the self-address setting is changed when an address switch is switched on the terminal device. means for transmitting the state of an address switch that has been switched in response to polling of a center device without having to do so, and a switching operation that occurs after a certain period of time has elapsed from the switching operation of the address switch to the point at which the center device can confirm the switching operation of the address switch. A CATV system comprising means for changing the setting of a self-address to the state of an address switch. 2. In the CATV system according to claim 1, when the center device determines that the address switch has been switched based on the information transmitted from the terminal device, an abnormality is displayed and the address switch is switched. A CATV system characterized by comprising means for sending a control signal disabling use of a terminal device.