Bi-directional digital communication network
First Claim
1. A low frequency bidirectional digital communication unit for use over coaxial cables of the cable TV system type, for requesting the performance of services by transmitting data to a central computer comprising:
- address byte register means for registering an address codeword associated with said unit,modem control code register means for registering a data word corresponding to services requested by said unit,shift register means coupled to said address byte register means and said modem control code register means for receiving the contents of said address byte register means and the contents of said modem control code register means in parallel and for shifting said address codeword and said data word out of said data shift register serially to provide a serial output to the central computer on the coaxial cable, andtransmitter modulator means coupled to the serial output of said shift register means for transmitting said serial output of said shift register means to said central computer on a low frequency carrier wave to request the performance of services.
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Accused Products
Abstract
A bi-directional digital communication unit for requesting the performance of services by transmitting data to a central computer complex for purposes of processing the data to utilize it to initiate the performance of the requested services and for receiving data from the central computer complex for purposes of determining whether the request for the performed services was received and the performance of the requested services was initiated. Data is transmitted from the central computer to the communication unit on a carrier wave at a first low frequency F1 and data is transmitted from the communication unit to the central computer at a second low frequency F2. The data received by the system, on the carrier wave having frequency F1, is demodulated and applied to valid address check means to determine if the central computer has transmitted a valid address to the unit. A modem register provides a data word which identifies the services that are requested by the user and transmits this data word to a data shift register which, if the system has received a valid address from the central computer, transmits the data word to the central computer, on a carrier wave at frequency F2, to initiate the performance of the requested services. The system includes a receiver data register which, after a subsequent valid address by the central computer of the communication system, registers the receipt by the unit of a data word from the central computer signifying the receipt by the central computer of the request for services, and controls visual displays in the modem control code generator to visually inform the user of the receipt by the central computer of the data word generated by the modem control code generator and the initiation of the performance of the requested services. The system includes a master clock frequency divider and control logic for providing timing and logic pulses to synchronize the operation of the system and coordinate it with that of the central computer.
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Citations
22 Claims
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1. A low frequency bidirectional digital communication unit for use over coaxial cables of the cable TV system type, for requesting the performance of services by transmitting data to a central computer comprising:
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address byte register means for registering an address codeword associated with said unit, modem control code register means for registering a data word corresponding to services requested by said unit, shift register means coupled to said address byte register means and said modem control code register means for receiving the contents of said address byte register means and the contents of said modem control code register means in parallel and for shifting said address codeword and said data word out of said data shift register serially to provide a serial output to the central computer on the coaxial cable, and transmitter modulator means coupled to the serial output of said shift register means for transmitting said serial output of said shift register means to said central computer on a low frequency carrier wave to request the performance of services. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of transmitting address codewords and data words in a cable TV system over a coaxial cable between a bidirectional subscriber communication unit and a central computer complex comprising the steps of:
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transmitting at a first low frequency a plurality of address codewords from said central computer complex to each said subscriber unit in successive order; receiving each of said plurality of address codewords at said unit; comparing each of said address codewords with an internally hard-wired address codeword associated with each said unit for ascertaining the receipt by said unit of a valid address codeword identifying said unit from the central computer complex; transmitting at a second low frequency said address codeword associated with said unit and a data word identifying services including television programming desired at the location of said unit from said unit to said central computer complex subsequent to the receipt by said unit of a valid address codeword from said central computer complex; and transmitting a confirmatory data codeword from said central computer complex associated with the address codeword identifying the originating communication unit. - View Dependent Claims (12, 13)
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14. In a cable TV type system for transmitting requests for services between a plurality of receiving stations, each having associated bidirectional communication units, and a central computer and service supplying complex, the improvements comprising:
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means at each said communication unit for registering a unique address codeword associated with said unit; means at each said communication unit for periodically receiving and recognizing digital address codewords transmitted to said communication unit at a first predetermined low frequency, and in a predetermined time slot allocated to each cable TV subscriber; means at each said communication unit for registering service requests including television programming requests originated by the cable TV subscriber at the location of said communications unit, in digital form; means at each said communication unit for transmitting to the central computer and service supplying complex, a digital signal including first the unique address of the communications unit, and secondly, the nature of the service request at a second predetermined low frequency; and means at each said communications unit for receiving a confirmatory digital signal, including both the unique address and the desired service codes, transmitted at said first predetermined low frequency, and for verifying the correctness of the implemented service signal being sent back from the central complex. - View Dependent Claims (15, 16, 17)
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18. In a Pay TV type system for transmitting requests for services between a plurality of receiving stations each having associated bidirectional communication units, and a central computer and service supplying complex, the improvements comprising:
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means at each said communication unit for registering a unique address code word associated with said unit; means at each said communication unit for periodically receiving and recognizing digital address codewords transmitted to said communication unit at a first predetermined low frequency, and in a predetermined time slot allocated to each Pay TV subscriber; means at each said communication unit for registering service requests including television programming requests, originated by the Pay TV subscriber at the location of said communications unit, in digital form; means at each said communication unit for transmitting to the central computer and service supplying complex, a digital signal representing the nature of the service request in the response time period allocated to each specific communication unit, at a second predetermined low frequency; and means at each said communications unit for receiving a confirmatory digital signal, including both the unique address and the desired service codes, transmitted at said first predetermined low frequency, and for verifying the correctness of the implemented service signal being sent back from the central complex. - View Dependent Claims (19, 20, 21, 22)
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Specification