Data communication system with increased effective bandwidth
First Claim
1. A communication system with a network for interconnecting a plurality of user devices having means for transmitting signals to and receiving signals from said communications system, said communication system having means for providing a plurality of frequency multiplexed communication channels operating on different frequency bands for concurrent communication between said user devices,wherein one or more but not all of said channels are dedicated as local service channels employing designated local frequencies,said communication system including frequency selective isolation means connected into said network intermediately between user devices, thereby subdividing said network into a plurality of local subnets, each local subnet interconnecting a plurality of said user devices,said frequency selective isolation means including means for blocking only the frequencies used by said local service channels from being transmitted from any of said local subnets to another while enabling transmission of frequencies other than those used by said local service channels between user devices connected on different subnets to isolate said subnets from one another as to the local service channels only,said communication system providing communications on a particular one of said local frequencies between two of said user devices both connected on a first of said subnets while concurrently and without interference providing communications on the same particular local frequency between two of said user devices both connected on a second of said subnets, while concurrently and without interference providing communications on a frequency other than local frequencies between user devices connected on different subnets.
8 Assignments
0 Petitions
Accused Products
Abstract
A broadband data communication system provides effective increased bandwidth for the transmission of electrical information signals in the system. The signal transmission medium is a coaxial cable having main receive and transmit branches, and having drop line pairs connected to the main branches at junction points. A plurality of user devices is connected to each drop line pair, including a particular set connected to a particular pair. Each user device of the set can transmit and receive signals of local frequencies in a selected bandwidth. Frequency isolation means is connected to the particular drop line pair adjacent its junction point, and passes signals of the local frequencies only from the transmit drop line to the receive drop line, while blocking signals of the local frequencies from transmission over the main cable branches. The particular set of user devices and the filter isolation means together define a subnet. Other subnets can use the same bandwidth of local frequencies without interference, thereby increasing the effective bandwidth of the system.
For communication between subnets, a master unit is provided in a subnet which can receive and transmit both at the local frequencies and at master frequencies outside the selected bandwidth; the frequency isolation means passes the master frequencies. The master translates communications from the subnet devices, at local frequencies, into master frequencies for transmission out of the subnet, and receives communications from outside the subnet at master frequencies for translation to local frequencies and transmission to the user devices of the subnet.
154 Citations
3 Claims
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1. A communication system with a network for interconnecting a plurality of user devices having means for transmitting signals to and receiving signals from said communications system, said communication system having means for providing a plurality of frequency multiplexed communication channels operating on different frequency bands for concurrent communication between said user devices,
wherein one or more but not all of said channels are dedicated as local service channels employing designated local frequencies, said communication system including frequency selective isolation means connected into said network intermediately between user devices, thereby subdividing said network into a plurality of local subnets, each local subnet interconnecting a plurality of said user devices, said frequency selective isolation means including means for blocking only the frequencies used by said local service channels from being transmitted from any of said local subnets to another while enabling transmission of frequencies other than those used by said local service channels between user devices connected on different subnets to isolate said subnets from one another as to the local service channels only, said communication system providing communications on a particular one of said local frequencies between two of said user devices both connected on a first of said subnets while concurrently and without interference providing communications on the same particular local frequency between two of said user devices both connected on a second of said subnets, while concurrently and without interference providing communications on a frequency other than local frequencies between user devices connected on different subnets.
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2. A communication system for interconnecting a plurality of user devices having means for transmitting signals to and receiving signals from said communications system, and communication system having means for providing a plurality of frequency multiplexed communication channels operating on different frequency bands for concurrent communication between said user devices, the communication system having a network with a medium comprising a receive branch and a transmit branch, the receive branch transmitting signals in the direction away from a head end and the transmit branch transmitting signals in the direction towards the head end, the branches being connected at the head end to pass signals from the transmit branch to the receive branch,
wherein one or more but not all of said channels are dedicated as local service channels employing designated local frequencies, and said system includes frequency selective isolation means connected into said network intermediately between user devices, thereby subdividing said network into a plurality of subnets, each subnet interconnecting a plurality of said user devices, each said frequency selective isolation means being connected into the network with connections to both the receive branch and the transmit branch looking towards the head end, and to both the receive branch and to the transmit branch looking away from the head end, each said frequency selected isolation means including means for reemitting on the receive branch in the direction away from the head end signals on said local frequencies entering the frequency selected isolation means on the transmit branch from the direction away from the head end, and means for reemitting on the receive branch in the direction away from the head end signals on other than local frequencies entering the frequency selected isolations means on the receive branch from the head end direction, means for reemitting on the transmit branch in the direction toward the head end signals on other than local frequencies entering the frequency selected isolations means on the transmit branch from the direction away from the head end, means for blocking signals on local frequencies from transmission between one subnet and another, said communication system providing communications on a particular one of said local frequencies between two of said user devices both connected on a first of said subnets while concurrently and without interference providing communications on the same particular local frequency between two of said user devices both connected on a second of said subnets, while concurrently and without interference providing communications on a frequency other than local frequencies between user devices connected on different subnets.
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3. A combination, including
a communications subnet for connection to a communication system at a junction point, said subnet interconnecting a plurality of user devices having means for transmitting signals to and receiving signals from said communications system, the subnet and the communications system having a communications medium comprising a receive branch and a transmit branch, the receive branch of the subnet transmitting signals in the direction junction point-toward-user devices and the transmit branch of the subnet transmitting signals in the direction user devices-towards-junction point, and an interfacing device interfacing the subnet to the communication system, said interfacing device including means for receiving signals on predesignated local frequencies from the transmit branch of the subnet and reemitting them onto the receive branch of the subnet, means for receiving signals on other than said predesignated local frequencies from the transmit branch of the subnet and reemitting them onto the transmit branch of the communications system, means for receiving signals on other than said predesignated local frequencies from the receive branch of the communications system and reemitting them onto the receive branch of the communications system, means for blocking signals on said predesignated local frequencies from being transmitted between the subnet and the communications system, said combination providing communications on said local frequencies between user devices both connected on said subnet without interferring with communications of user devices both connected elsewhere in said communications system and using the same local frequency, and further providing communications on frequencies other than said local frequencies between a user device connected on said subnet and user devices of the communication system connected elsewhere than on said subnet.
Specification