US4245245A — Interactive CATV system

Claim 1

Independent Claim 381 words

In a CATV system having a central computer at a central station, a multi-channel program generator for generating programs, some of which are premium programs requiring payment and others of which are restricted premium programs to be available only to predetermined subscribers, and a plurality of individual subscriber terminals each controlling program selection for an associated TV set and coupled by a cable system to the central station, the combination comprising: means disposed at said central station and coupled to the multi-channel program generator for transmitting scrambled program signals on all premium channels; means for subscriber program selection at each subscriber terminal; selectively operable converter means and controllable descrambling means at each subscriber terminal for providing descrambling of premium programs in a selected channel in response to program selection, said converter means comprising variable frequency oscillator means coupled to provide selected programs in a single chosen channel, and further including means responsive to components of the program signals for precisely adjusting the frequency of the variable frequency oscillator; terminal processor means disposed at each of said terminals coupled to respond to said means for program selection and externally supplied command signals and coupled selectively to control reception of programs; means at each subscriber terminal coupled to said terminal processor means for indicating authorization by the subscriber for premium program payment and wherein said terminal processor means inhibits reception of premium programs in the absence of an indication of authorization; means at each subscriber terminal responsive to the processor means thereat and to an identifying address for the terminal for transmitting an encoded upstream data message as to terminal status to the central station; central processor means coupled to the transmission network for transmitting successive messages to the different subscriber terminals, said messages including identifying addresses and command signals containing subscriber data; and means disposed at said central station and responsive to subscriber selection and received upstream messages for transmitting commands selectively to inhibit reception of premium programs and to enable reception of requested restricted premium programs under central control and for recording only change of status at the subscriber terminals relative to premium programs, whereby the system monitors premium program usage in real time and access to premium and restricted premium programming is centrally controllable without modification of the subscriber terminal.

Claim 2

Dependent Claim 381 words

In a CATV system having a central computer at a central station, a multi-channel program generator for generating programs, some of which are premium programs requiring payment and others of which are restricted premium programs to be available only to predetermined subscribers, and a plurality of individual subscriber terminals each controlling program selection for an associated TV set and coupled by a cable system to the central station, the combination comprising: means disposed at said central station and coupled to the multi-channel program generator for transmitting scrambled program signals on all premium channels; means for subscriber program selection at each subscriber terminal; selectively operable converter means and controllable descrambling means at each subscriber terminal for providing descrambling of premium programs in a selected channel in response to program selection, said converter means comprising variable frequency oscillator means coupled to provide selected programs in a single chosen channel, and further including means responsive to components of the program signals for precisely adjusting the frequency of the variable frequency oscillator; terminal processor means disposed at each of said terminals coupled to respond to said means for program selection and externally supplied command signals and coupled selectively to control reception of programs; means at each subscriber terminal coupled to said terminal processor means for indicating authorization by the subscriber for premium program payment and wherein said terminal processor means inhibits reception of premium programs in the absence of an indication of authorization; means at each subscriber terminal responsive to the processor means thereat and to an identifying address for the terminal for transmitting an encoded upstream data message as to terminal status to the central station; central processor means coupled to the transmission network for transmitting successive messages to the different subscriber terminals, said messages including identifying addresses and command signals containing subscriber data; and means disposed at said central station and responsive to subscriber selection and received upstream messages for transmitting commands selectively to inhibit reception of premium programs and to enable reception of requested restricted premium programs under central control and for recording only change of status at the subscriber terminals relative to premium programs, whereby the system monitors premium program usage in real time and access to premium and restricted premium programming is centrally controllable without modification of the subscriber terminal.

Claim 3

Dependent Claim 46 words

The invention as set forth in claim 1 above, wherein said means for controlling the frequency comprises means responsive to the average level of the audio carrier component of the program signals for providing a control signal of selected nominal level to the variable frequency oscillator.

Claim 4

Dependent Claim 61 words

The invention as set forth in claim 2 above, wherein said means for program selection comprises means providing a plurality of selectable control voltages, and said converter means further comprises means responsive to changes in said selectable control voltages for disabling said means for providing a control signal for a selected interval after each change to prevent an AFC pull-in effect.

Claim 5

Dependent Claim 407 words

In a CATV system having a central computer at a central station, a multi-channel program generator for generating programs, some of which are premium programs requiring payment and others of which are restricted premium programs to be available only to predetermined subscribers, and a plurality of individual subscriber terminals each controlling program selection for an associated TV set and coupled by a cable system to the central station, the combination comprising: means disposed at said central station and coupled to the multi-channel program generator for transmitting scrambled program signals on all premium channels; means for subscriber program selection at each subscriber terminal; selectively operable converter means and controllable descrambling means at each subscriber terminal for providing descrambling of premium programs in a selected channel in response to program selection; terminal processor means disposed at each of said terminals coupled to respond to said means for program selection and externally supplied command signals and coupled selectively to control reception of programs; means at each subscriber terminal coupled to said terminal processor means for indicating authorization by the subscriber for premium program payment and wherein said terminal processor means inhibits reception of premium programs in the absence of an indication of authorization; means at each subscriber terminal responsive to the processor means thereat and to an identifying address for the terminal for transmitting an encoded upstream data message as to terminal status to the central station; central processor means coupled to the transmission network for transmitting successive messages to the different subscriber terminals, said messages including identifying addresses and command signals containing subscriber data; means disposed at said central station and responsive to subscriber selection and received upstream messages for transmitting commands selectively to inhibit reception of premium programs and to enable reception of requested restricted premium programs under central control and for recording only change of status at the subscriber terminals relative to premium programs, whereby the system monitors premium program usage in real time and access to premium and restricted premium programming is centrally controllable without modification of the subscriber terminal; power means at each of said terminals for enabling a subscriber's TV set to be plugged in for power, and including power sensor circuit means responsive to the level of power utilized to provide an indication of TV receiver operation to said terminal processor means; and wherein said terminal processor means is coupled to inhibit reception in the absence of an indication of TV receiver operation.

Claim 6

Dependent Claim 407 words

In a CATV system having a central computer at a central station, a multi-channel program generator for generating programs, some of which are premium programs requiring payment and others of which are restricted premium programs to be available only to predetermined subscribers, and a plurality of individual subscriber terminals each controlling program selection for an associated TV set and coupled by a cable system to the central station, the combination comprising: means disposed at said central station and coupled to the multi-channel program generator for transmitting scrambled program signals on all premium channels; means for subscriber program selection at each subscriber terminal; selectively operable converter means and controllable descrambling means at each subscriber terminal for providing descrambling of premium programs in a selected channel in response to program selection; terminal processor means disposed at each of said terminals coupled to respond to said means for program selection and externally supplied command signals and coupled selectively to control reception of programs; means at each subscriber terminal coupled to said terminal processor means for indicating authorization by the subscriber for premium program payment and wherein said terminal processor means inhibits reception of premium programs in the absence of an indication of authorization; means at each subscriber terminal responsive to the processor means thereat and to an identifying address for the terminal for transmitting an encoded upstream data message as to terminal status to the central station; central processor means coupled to the transmission network for transmitting successive messages to the different subscriber terminals, said messages including identifying addresses and command signals containing subscriber data; means disposed at said central station and responsive to subscriber selection and received upstream messages for transmitting commands selectively to inhibit reception of premium programs and to enable reception of requested restricted premium programs under central control and for recording only change of status at the subscriber terminals relative to premium programs, whereby the system monitors premium program usage in real time and access to premium and restricted premium programming is centrally controllable without modification of the subscriber terminal; power means at each of said terminals for enabling a subscriber's TV set to be plugged in for power, and including power sensor circuit means responsive to the level of power utilized to provide an indication of TV receiver operation to said terminal processor means; and wherein said terminal processor means is coupled to inhibit reception in the absence of an indication of TV receiver operation.

Claim 7

Dependent Claim 42 words

The invention as set forth in claim 4 above, wherein said terminal signal processor means includes means responsive to a change in the indication of TV receiver operation for switching said converter means to a selected channel to provide a refresh mode.

Claim 8

Dependent Claim 40 words

The invention as set forth in claim 5 above, wherein said system further includes actuable switch means providing a control voltage to said converter means, and circuit means responsive to said power sensor circuit means for activating said switch means.

Claim 9

Dependent Claim 226 words

In a CATV system having a two-way data transmission coupling between each of a plurality of subscribers terminals and a central station the combination comprising: central station program transmission means for transmitting unscrambled non-premium programs, and scrambled premium and restricted premium programs on different ones of multiple channels; central station data transmission means for successively interrogating individual subscribers terminals, said data transmission means providing a fixed length group address message for all subscribers in a group and subsequent fixed length downstream messages containing private address and command data for controlling reception of restricted premium programs; program selection means disposed at each subscriber terminal; controllable descrambler means disposed at each terminal for automatically descrambling selected premium programs; processor means at each terminal responsive to said program selection means and to downstream messages for transmitting pre-selected fixed length upstream messages as to program status when the appropriate private address is provided in a downstream message, said processor means being responsive to the appropriate private address only when immediately preceded by the proper group address and including means for enabling reception when the terminal is authorized to receive a restricted premium program, and terminating reception when the terminal is not authorized to receive a premium program; and central station independent timer means responsive to the occurrence of successive messages for indicating the existence of fault conditions in data transmission.

Claim 10

Dependent Claim 226 words

In a CATV system having a two-way data transmission coupling between each of a plurality of subscribers terminals and a central station the combination comprising: central station program transmission means for transmitting unscrambled non-premium programs, and scrambled premium and restricted premium programs on different ones of multiple channels; central station data transmission means for successively interrogating individual subscribers terminals, said data transmission means providing a fixed length group address message for all subscribers in a group and subsequent fixed length downstream messages containing private address and command data for controlling reception of restricted premium programs; program selection means disposed at each subscriber terminal; controllable descrambler means disposed at each terminal for automatically descrambling selected premium programs; processor means at each terminal responsive to said program selection means and to downstream messages for transmitting pre-selected fixed length upstream messages as to program status when the appropriate private address is provided in a downstream message, said processor means being responsive to the appropriate private address only when immediately preceded by the proper group address and including means for enabling reception when the terminal is authorized to receive a restricted premium program, and terminating reception when the terminal is not authorized to receive a premium program; and central station independent timer means responsive to the occurrence of successive messages for indicating the existence of fault conditions in data transmission.

Claim 11

Dependent Claim 248 words

In a CATV system having a two-way data transmission coupling between each of a plurality of subscribers terminals and a central station the combination comprising: central station program transmission means for transmitting unscrambled non-premium programs, and scrambled premium and restricted premium programs on different ones of multiple channels; central station data transmission means for successively interrogating individual subscribers terminals, said data transmission means providing a fixed length group address message for all subscribers in a group and subsequent fixed length downstream messages containing private address and command data for controlling reception of restricted premium programs; program selection means disposed at each subscriber terminal; controllable descrambler means disposed at each terminal for automatically descrambling selected premium programs; processor means at each terminal responsive to said program selection means and to downstream messages for transmitting pre-selected fixed length upstream messages as to program status when the appropriate private address is provided in a downstream message, said processor means being responsive to the appropriate private address only when immediately preceded by the proper group address and including means for enabling reception when the terminal is authorized to receive a restricted premium program, and terminating reception when the terminal is not authorized to receive a premium program; and undelayed response means at each terminal comprising a continually operating oscillator, gated frequency divider means activated in response to an appropriate downstream message, and means coupled to the processor means for keying the output of the frequency divider means with an upstream data message.

Claim 12

Dependent Claim 248 words

In a CATV system having a two-way data transmission coupling between each of a plurality of subscribers terminals and a central station the combination comprising: central station program transmission means for transmitting unscrambled non-premium programs, and scrambled premium and restricted premium programs on different ones of multiple channels; central station data transmission means for successively interrogating individual subscribers terminals, said data transmission means providing a fixed length group address message for all subscribers in a group and subsequent fixed length downstream messages containing private address and command data for controlling reception of restricted premium programs; program selection means disposed at each subscriber terminal; controllable descrambler means disposed at each terminal for automatically descrambling selected premium programs; processor means at each terminal responsive to said program selection means and to downstream messages for transmitting pre-selected fixed length upstream messages as to program status when the appropriate private address is provided in a downstream message, said processor means being responsive to the appropriate private address only when immediately preceded by the proper group address and including means for enabling reception when the terminal is authorized to receive a restricted premium program, and terminating reception when the terminal is not authorized to receive a premium program; and undelayed response means at each terminal comprising a continually operating oscillator, gated frequency divider means activated in response to an appropriate downstream message, and means coupled to the processor means for keying the output of the frequency divider means with an upstream data message.

Claim 13

Dependent Claim 184 words

In a CATV system having a plurality of subscribers, a system for addressing any selected individual subscriber on an asynchronous basis with a sufficiently short message such that all subscribers can be addressed within a relatively short time interval, the combination comprising: a transmission network including a main trunk, branch amplifiers coupling the main trunk to a plurality of branches and distribution means coupling each of the branches to an individual subscriber's location, the branches being arranged in groups; transmitting means for concurrently transmitting video programs and data messages in different parts of the frequency spectrum on said network; coding means coupled to said transmitting means for encoding messages for said individual subscribers, said messages comprising sync, group address, private address and command data, the sync data comprising a selected sequence of binary-valued representations of one value, the data patterns being bisected by a binary-valued signal of the opposite value to the sync data value into bit sequence lengths that are shorter than the length of the sync bit sequence; and means disposed at the subscriber terminals for responding to the appropriate private address.

Claim 14

Dependent Claim 184 words

In a CATV system having a plurality of subscribers, a system for addressing any selected individual subscriber on an asynchronous basis with a sufficiently short message such that all subscribers can be addressed within a relatively short time interval, the combination comprising: a transmission network including a main trunk, branch amplifiers coupling the main trunk to a plurality of branches and distribution means coupling each of the branches to an individual subscriber's location, the branches being arranged in groups; transmitting means for concurrently transmitting video programs and data messages in different parts of the frequency spectrum on said network; coding means coupled to said transmitting means for encoding messages for said individual subscribers, said messages comprising sync, group address, private address and command data, the sync data comprising a selected sequence of binary-valued representations of one value, the data patterns being bisected by a binary-valued signal of the opposite value to the sync data value into bit sequence lengths that are shorter than the length of the sync bit sequence; and means disposed at the subscriber terminals for responding to the appropriate private address.

Claim 15

Dependent Claim 35 words

The invention as set forth in claim 9 above, wherein said network means includes means responsive to said group address signals for blocking signals from the branches that are other than in the selected group.

Claim 16

Dependent Claim 31 words

The invention as set forth in claim 9 above, wherein said encoding means provides frequency shift keyed biphase signals, and wherein said means at the subscriber terminals includes bandpass filter means.

Claim 17

Dependent Claim 80 words

The invention as set forth in claim 9 above, wherein said encoding means provides two different frames of data for a group of individual subscribers, a first of said frames comprising a synchronizing bit sequence followed by two groups of group address sequences separated by a bisecting bit and the second of said frames comprises an initial synchronizing bit sequence followed by a first and second private address portion separated by a bisecting bit, and a data command bit portion.

Claim 18

Dependent Claim 42 words

The invention as set forth in claim 12 above, wherein said means responsive to the transmitted signals at the subscriber's unit respond to the second frame only if the group address for their group is correctly identified in a prior first frame.

Claim 19

Dependent Claim 31 words

The invention as set forth in claim 13 above, wherein said means at the subscriber terminals includes means for reordering the return message to provide higher priority indications under predetermined circumstances.

Claim 20

Dependent Claim 49 words

The invention as set forth in claim 11 above, wherein said means for transmitting information from said terminal comprises a continuously operable oscillator and frequency dividing means coupled to the output thereof, and means for rendering said frequency divider means operable to commence undelayed generation of a response frequency.

Claim 21

Dependent Claim 253 words

In a two-way CATV system having a plurality of subscriber terminals coupled by a cable network to a central station and interchanging digital data messages with the central station when interrogated, downstream messages to the terminals being frequency shift keyed fixed length messages including address and command information, and upstream messages being phase shift keyed fixed length messages including subscriber terminal status and optional additional information, the terminals each including address recognition, data assembly and data storage circuits for preparing upstream messages for transmission in response to interrogation, a system for rapid and reliable interrogation of a large number of terminals in variable sequences comprising: central station transmitter means providing downstream message frames including a fixed length initial synchronizing sequence of like bits, and further including fixed length data sequences of shorter length than the synchronizing sequence and separated by bisecting bits of opposite binary value to the bits of the synchronizing sequence, the data sequence including at least one address sequence; and means at each terminal responsive to the downstream message frame for generating an upstream message frame having an initial synchronizing sequence of like bits and subsequent data sequences of shorter length than the synchronizing sequence and being separated by bisecting bits of opposite binary value to the bits of the synchronizing sequence, the upstream message frame being shorter than the downstream message frame, whereby messages comprising short frames can be transmitted at arbitrary times through the message network and the data can be detected reliably by pre-synchronizing the received messages.

Claim 22

Dependent Claim 253 words

In a two-way CATV system having a plurality of subscriber terminals coupled by a cable network to a central station and interchanging digital data messages with the central station when interrogated, downstream messages to the terminals being frequency shift keyed fixed length messages including address and command information, and upstream messages being phase shift keyed fixed length messages including subscriber terminal status and optional additional information, the terminals each including address recognition, data assembly and data storage circuits for preparing upstream messages for transmission in response to interrogation, a system for rapid and reliable interrogation of a large number of terminals in variable sequences comprising: central station transmitter means providing downstream message frames including a fixed length initial synchronizing sequence of like bits, and further including fixed length data sequences of shorter length than the synchronizing sequence and separated by bisecting bits of opposite binary value to the bits of the synchronizing sequence, the data sequence including at least one address sequence; and means at each terminal responsive to the downstream message frame for generating an upstream message frame having an initial synchronizing sequence of like bits and subsequent data sequences of shorter length than the synchronizing sequence and being separated by bisecting bits of opposite binary value to the bits of the synchronizing sequence, the upstream message frame being shorter than the downstream message frame, whereby messages comprising short frames can be transmitted at arbitrary times through the message network and the data can be detected reliably by pre-synchronizing the received messages.

Claim 23

Dependent Claim 22 words

The invention as set forth in claim 16 above, wherein the upstream and downstream messages each comprise biphase signals with internal clocking.

Claim 24

Dependent Claim 58 words

The invention as set forth in claim 16 above, wherein said central station transmitter means provides a unique group address message frame for a plurality of terminals, followed by a succession of private message frames each including private address and command data, and wherein said system further includes means for disabling all of the terminals in non-addressed groups.

Claim 25

Dependent Claim 45 words

The invention as set forth in claim 18 above, wherein said terminals each in addition include means for assembling terminal information on a priority basis, and further means for including highest priority information in the upstream message, to the capacity of the data portion thereof.

Claim 26

Dependent Claim 78 words

The invention as set forth in claim 19 above, wherein said system further includes, at each terminal, a continuously running oscillator having a selected frequency, gated frequency divider means coupled to provide a divided frequency output signal as a basis for generation of the upstream message upon application of a controlled signal, and means responsive to the reception of the appropriate private address interrogation for providing a controlled signal to initiate operation of said gated frequency divider means.

Claim 27

Dependent Claim 77 words

The invention as set forth in claim 20 above, wherein said system further includes means at said central station for interrupting the interrogating sequence, and first means for controlling said means for interrupting in response to the failure to detect a receiving message at greater than a predetermined interval after transmission of a downstream message, and second means for causing an interrupt in response to the occurrence of greater than a predetermined delay between successive received messages.

Claim 28

Dependent Claim 130 words

In a two-way CATV system in which upstream and downstream digital data are transmitted in frequency multiplexed fashion between a central station and a plurality of subscriber terminals, the combination comprising: central station transmitter means providing fixed length downstream message frames; and terminal transmitter means providing fixed length upstream message frames in response to downstream message frames, downstream and upstream message frames each having an initial fixed length synchronizing sequence of binary digits of a given value, and being followed by at least two fixed length sequences of binary value data, each shorter in length than the initial sequence, and separated by a bisecting bit of opposite binary value to the binary value of the synchronizing sequence bits, wherein the upstream message is shorter in length than the downstream message.

Claim 29

Dependent Claim 130 words

In a two-way CATV system in which upstream and downstream digital data are transmitted in frequency multiplexed fashion between a central station and a plurality of subscriber terminals, the combination comprising: central station transmitter means providing fixed length downstream message frames; and terminal transmitter means providing fixed length upstream message frames in response to downstream message frames, downstream and upstream message frames each having an initial fixed length synchronizing sequence of binary digits of a given value, and being followed by at least two fixed length sequences of binary value data, each shorter in length than the initial sequence, and separated by a bisecting bit of opposite binary value to the binary value of the synchronizing sequence bits, wherein the upstream message is shorter in length than the downstream message.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1984-01-13	1984-07-14	1985-01-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1988-01-13	1988-07-14	1989-01-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1992-01-13	1992-07-14	1993-01-13	$7700.00	Window Closed / Lapsed

Interactive CATV system

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