Patent Application
20120066723
This invention relates to distribution and networking of television, video and other signals, installation of such distribution systems, and control of television sets.
Certain aspects of this invention find particular application in a media distribution/networking system for use in a hotel. It will be understood, however, that the invention can also be applied to other distribution/networking systems. Likewise, as used herein, the term “hotel” is preferably to be understood as encompassing any form of establishment where guests are temporarily allocated a room or similar or part thereof whether for payment or not.
In a traditional hotel media distribution system, different media services, such as television programs, radio programs and movies are broadcast around the hotel using a distribution network of coaxial cable. Each service is provided on the coaxial cable as an analogue signal with a different channel frequency, and the receiving equipment (such as a television) in each hotel room can be tuned to the required channel to receive the desired service.
Similarly, in the cable distribution of television signals to dwellings in a neighborhood (“cable television”), each program is provided on the cable as a signal with a different channel frequency, and the receiving equipment in each dwelling can be tuned to the required channel to receive the desired program.
Low-grade coaxial cable (such as RG59 cable) that has traditionally been used in hotel distribution networks has a typical bandwidth of 460 MHz. An analogue television signal occupies a bandwidth of 6 MHz. There is therefore a limit of about seventy-six channels that can be used in such a system. There is a desire to increase the range of services that are available to each hotel room or dwelling and to facilitate the provision of room-specific or dwelling-specific services.
In the following, references are made to a server, a receiver, a network, a conductor, a 2-way amplifier, a first circuit board, and a second circuit board. Such a server may alternatively be replaced by a means for providing signals, preferably digital television/video signals; such a receiver may alternatively be replaced by a means for receiving signals, preferably digital television/video signals; such a network may alternatively be replaced by a means for connecting a server to receivers, or for connecting the providing means to the receiving means; such a conductor may alternatively be replaced by a means for carrying a plurality of signals; such a 2-way amplifier may alternatively be replaced by a means for amplifying/maintaining the signal level of signals; such a first circuit board may alternatively be replaced by a first control means; and such a second circuit board may alternatively be replaced by a second control means.
One aspect of the invention provides a system for distributing television/video signals to different locations (such as different rooms in a hotel, or different dwellings in a neighborhood), the system comprising a server capable of providing digital television/video signals for a plurality of programs, a plurality of receivers each at a respective one of said locations, and a network connecting the server to the receivers, each receiver being operable to select a required one of the programs and to communicate the selection to the server, the server being responsive to such a selection to transmit the digital television/video signal for the selected program over the network addressed to the receiver that selected that program, and each receiver being responsive to the digital television/video signal that is addressed to that receiver so that point-to-point communication is established from the server to that receiver.
By providing the services by way of digital, rather than analogue, signals, and using a digital point-to-point network (for example using a switched internet protocol (IP)) between one or more servers and the receivers, the modern requirements for such a system can more easily be met.
A bandwidth to each receiver of 10 Mbps is sufficient for video, and therefore in one embodiment of the invention a substantial part of a cable run of the network from the server to the receivers may be provided by data grade twisted-pair cable, such as twisted-pair cable that substantially complies with or exceeds the specification of ANSI/EIA/TIA-568-1991, Category 3, and more preferably complies with or exceeds the specification of Category 5, i.e. that type of cable currently normally used for 100BaseT or 100 baseTX computer networks.
The installation of such cabling and any necessary switches in a new hotel would not cause a problem. However, the installation of such cabling into an existing hotel may many instances be difficult, expensive and inconvenient. Nevertheless, most hotels have a telephone system, with a telephone in each room. Telephone-grade twisted pair cabling is not designed for use in a television/video network and is of inferior quality to standard network cable (Category 5), but it has been realized that it can be used for the transmission of digital television/video signals in a controlled environment such as a hotel.
Accordingly, in another embodiment of the invention, a substantial part of a cable run of the network from the server to the receivers is provided by telephone-grade twisted-pair cable.
Features which distinguish conventional telephone-grade twisted-pair cable from standard network cable are:
it falls below the specification of ANSI/EIA/TIA-568-1991, Category 3;
it may be in accordance with British Telecommunications specification CW 1308;
it may be of the type known as Category 2 twisted-pair (even though category 2 is no longer a standard specified by ANSI/EIA/TIA);
it has a characteristic impedance at 16 MHz substantially higher than 115Ω; and/or
for a run to a single telephone, it has less than four twisted pairs.
Preferably, the system further includes a telephone connected by a first splitter to the network, in particular to the telephone grade cable, adjacent the respective receiver, and a telephone exchange connected by a second splitter to the network, in particular to the telephone grade cable, remote from the respective receiver. Accordingly, an existing telephone system can continue to be used.
Another aspect of the invention provides a receiver for use in a system for distributing television/video signals to different locations, the system comprising a server capable of providing digital television/video signals for a plurality of programs, and the receiver comprising means for enabling connection to the server by means of a network (for example, a connector, for instance a telephone or coaxial connector), means for selecting a required one of the programs (for example a keypad), and means for communicating the selection to the server (for example, a transmitter), the receiver being responsive to a digital television/video signal that is transmitted by the server over the network and addressed to that receiver so that point-to-point communication is established from the server to that receiver, and preferably, the receiver is tuned to a given channel.
Preferably, the receiver further comprises means for converting the digital signals to analogue signals (for instance an analogue to digital processor) for supply to a picture/sound reproduction means (for example a visual display unit, for example a television), and the digital to analogue converting means may include means for decompressing the digital signals (for example using decompression techniques such as MP3 or MPEG2 decompression techniques).
Another aspect of the invention provides a receiver for use in a system for distributing television/video signals to different locations, the system comprising a server capable of providing digital television/video signals for a plurality of programs, the receiver comprising a connection to the server via a network, a selector for selecting a required one of the programs, and a transmitter for communicating the selection to the server, the receiver being responsive to a digital television/video signal that is transmitted by the server over the network and addressed to that receiver so that point-to-point communication is established from the server to that receiver.
Another aspect of the invention provides a method of installing such a distribution system for premises having an existing arrangement of telephone cable for a telephone system of the premises, the method including using at least part of the existing arrangement of telephone cable in the network of the distribution system.
As mentioned above, the installation of new Category 5 cabling into an existing hotel may in many instances be difficult, expensive and inconvenient. However, most hotels have an existing coaxial cable network for distributing analogue television signals. Conventional analogue television coaxial cable is of inferior quality, but it has been realized that it can be used for the transmission of digital television/video signals in a controlled environment such as a hotel.
Accordingly, in a further embodiment of the invention, a substantial part of a cable run of the network from the server to the receivers is provided by a conductor, preferably coaxial cable, arranged to carry the digital television/video signals for those receivers, chose signals being provided on respective channels each allocated to a respective one of the receivers, and each receiver being tuned to its respective channel.
As mentioned above, RG59 coaxial cable places a limit of about seventy-six on the number of channels and therefore on the number of programs that it can carry in a conventional arrangement. However, with this embodiment of the invention, there is no limit that the cable places on the number of programs or other services that the server can make available, because each channel is associated with a particular receiver, rather than a particular program. There is a limit on the number of receivers that can be connected to the cable if each receiver is to have its own channel, but in the context of hotel distribution, or neighborhood cable television distribution, this limit is not a problem.
Especially in a hotel environment, the coaxial cable may be analogue television grade coaxial cable, because it is relatively inexpensive and may already be installed. Features which distinguish such cable from, for example, the coaxial cable which is used in 10 Base2 computer networks are that:
it has a characteristic impedance of 75Ω, as opposed to 50Ω; and/or
it is substantially in accordance with specification RG59 or RG62.
Preferably, each of the plurality of receivers is connected to the coaxial cable via a cable modem whose tuning is preset to the channel allocated to the respective receiver. Also, the server is preferably connected to the coaxial cable via a cable modem that is controlled by the server to place the digital television/video signal for the program selected for each receiver on the channel allocated to that receiver.
Another aspect of the invention provides a method of installing such a distribution system for premises having an existing arrangement of coaxial cable for distributing analogue television signals in or to the premises, the method including the step of using at least part of the existing arrangement of coaxial cable in the network of the distribution system.
A further aspect of the invention provides a corresponding method of distributing television/video signals to different locations, the method comprising providing a server capable of providing digital television/video signals for a plurality of programs, providing a plurality of receivers each at a respective one of said locations, providing a network connecting the server to the receivers, each receiver selecting a required one of the programs and communicating the selection to the server, the server responding to such a selection and transmitting the digital television/video signal for the selected program over the network addressed to the receiver that selected that program, and each receiver responding to the digital television/video signal that is addressed to that receiver so that point-to-point communication is established from the server to that receiver. Preferably, the transmitting includes transmitting the digital television/video signal over telephone-grade twisted-pair cable and/or transmitting the digital television/video signal over coaxial cable on a channel allocated according to the receiver to which the signal is being sent, and each receiver being tuned to its respective channel.
It should be noted that the channel allocation feature described above in relation to transmission of digital television/video signals over coaxial cable provides similar advantages when applied to the transmission of other signals over other conductors. Accordingly, another aspect of the invention provides a networked system comprising a server and a plurality of devices connected to the server by a network, at least part of the network being provided by a conductor for carrying a plurality of signals between the server and the devices, the signals being multiplexed on the conductor each on a preset channel allocated according to the device so that each device has a respective preset one of the channels. The signals may be digital signals. Preferably, the signals are frequency-multiplexed and/or phase-multiplexed on the conductor. The conductor may perform different processes depending on the result of the comparison.
Another aspect of the invention provides a corresponding method of operation of a networked system comprising a server and a plurality of devices at different locations connected to the server by a network, at least part of the network being provided by a conductor for carrying a plurality of signals between the server and the devices, the method including the step of multiplexing the signals on the conductor each on a preset channel allocated according to the device so that each device has a respective preset one of the channels.
A further aspect of the invention provides a method of operation of a networked system comprising a server and a plurality of devices at different locations connected to the server by a network, at least part of the network being provided by coaxial cable having at least one branch which is divided at a node into at least two sub-branches in a path direction extending away from the server, and a two-way amplifier being provided at the node to amplify/maintain the signal level of signals passing from the sub-branches to the branch in addition to the signal level of signals travelling from the branch to the sub-branches, the method comprising the step of transmitting a signal from at least one of the devices to the server generally at the same time as transmitting a signal from the server to the devices.
Although it is known to use two-way amplifiers in coaxial distribution systems, they are employed to facilitate relocation of the server rather than for generally simultaneous amplification of signals in the two directions.
Another aspect of the invention provides a method of operation of a networked system comprising a server and a plurality of devices at different locations connected to the server by a network, at least part of the network being provided by coaxial cable having at least one branch which is divided at a node into at least two sub-branches in a path direction extending away from the server, and a two-way amplifier being provided at the node to amplify/maintain the signal level of signals passing from the sub-branches to the branch in addition to the signal level of signals travelling from the branch to the sub-branches, the method comprising transmitting the signals from the server to the devices on different channels allocated according to the device and transmitting signals from each device to the server on the same channel as is used for transmission from the server to that device.
Again, although it is known to use two-way amplifiers in coaxial distribution systems, they are not employed in the case where channels are allocated on a per device or per user basis.
It will be appreciated that a particular system can advantageously employ one or both of the latter two aspects of the invention.
A further aspect of the invention provides a networked system comprising a server and a plurality of devices at different locations connected to the server by a network, at least part of the network being provided by coaxial cable having at least one branch which is divided at a node into at least two sub-branches in a path direction extending away from the server, and a two-way amplifier being provided at the node to amplify/maintain the signal level of signals passing from the sub-branches to the branch in addition to the signal level of signals travelling from the branch to the sub-branches, the system being operable to transmit a signal from at least one of the devices to the server generally at the same time as a signal is transmitted from the server to the devices.
A further aspect of the invention provides a networked system comprising a server and a plurality of devices at different locations connected to the server by a network, at least part of the network being provided by coaxial cable having at least one branch which is divided at a node into at least two sub-branches in a path direction extending away from the server, and a two-way amplifier being provided at the node to amplify/maintain the signal level of signals passing from the sub-branches to the branch in addition to the signal level of signals travelling from the branch to the sub-branches, the system being arranged to transmit the signals from the server to the devices on different channels allocated according to the device, and to transmit signals from each device to the server on the same channel as is used for transmission from the server to that device.
A further aspect of the invention provides a system for distributing television/video/radio/audio signals to different locations, the system comprising means for receiving analogue television or radio signals or for generating analogue video or audio signals (for instance a reception and production centre, comprising for instance a central receiver, or a production suite), means for converting the analogue signals to digital signals (for instance an analogue to digital processor) and supplying the digital signals to a server, a plurality of receivers each at a respective one of said locations, and a network connecting the server to the receivers, each receiver including means for converting the digital signals to analogue signals (for instance, a digital to analogue processor) for supply to a picture/sound reproduction means (for example a visual display unit, for example a television).
Therefore, although digital networking is employed with its associated advantages, the source signals may be analogue signals and the output signal may be used by a picture/sound reproduction means (for instance a visual display unit such as a television) with a conventional analogue input.
The analogue to digital converting means preferably includes means for compressing the digital signals to a standard compressed digital format (for instance a processor, in particular a processor adapted to operate MPEG2 or MP3 compression routines), and each digital to analogue converting means preferably includes means for decompressing the digital signals. This reduces the amount of network traffic.
The receiving means may include an aerial for receiving modulated terrestrial analogue television/radio signals for a plurality of programs, and means for demodulating the modulated signal for at least one of the programs (for example a processor).
Additionally or alternatively, the receiving means may include a satellite dish for receiving scrambled and multiplexed satellite analogue television signals for a plurality of programs, and means for descrambling and demultiplexing the signal for at least one of the programs (for example a processor). However, since many satellite distributors use proprietary software and hardware (their “set top box”) to ensure that programs are only received by registered subscribers, the receiving means may alternatively or additionally include a satellite receiver, for instance a satellite dish, for receiving scrambled and multiplexed satellite analogue television signals for a plurality of programs, means for descrambling and demultiplexing the signal for at least one of the programs to produce an intermediate signal, means for modulating an RF signal with the intermediate signal, and means for demodulating the modulated RF signal. The descrambling, demultiplexing and modulating may therefore be provided by a conventional set top box.
Another aspect of the invention provide a system for distributing television/video/radio/audio signals to different locations, the system comprising a reception and production centre for receiving analogue television or radio signals or for generating analogue video or audio signals, a processor for converting the analogue signals to digital signals and supplying the digital signals to a server, a plurality of receivers each at a respective one of said locations, and a network connecting the server to the receivers, each receiver including a digital to analogue convertor for converting the digital signals to analogue signals for supply to an output device.
Another aspect of the invention provides a corresponding method of distributing television/video/radio/audio signals to different locations, comprising: receiving analogue television or radio signals or generating analogue video or audio signals, converting the analogue signals to digital signals, supplying the digital signals to a server, distributing the digital signals over a network to a plurality of receivers each at a respective one of said locations, and, at each receiver, converting the digital signal to an analogue signal and reproducing a picture/sound from the analogue signal.
The various systems and methods mentioned above are particularly applicable in the case where the different locations are different rooms in a hotel.
In a conventional hotel television distribution system using analogue signals on coaxial cable, the coaxial cable can be connected directly to the aerial input of a conventional television set. With the distribution systems of the invention as described above, if a television set with an analogue input, such as an RGB, CUBS or S/VHS input, is to be used, a decoder also needs to be used. Also, nowadays, many television sets have the ability to be controlled via a control interface, and this can be used to advantage, for example so that the server can turn on the television and display the time for an alarm call or welcome message for a hotel guest. However, an industry standard for such a control interface does not yet exist.
A further aspect of the invention provides a control system for a television set, comprising a first circuit on at least one first circuit board for receiving a digital video signal from a network and for decoding the digital video signal to produce a decoded video signal for supply to a standard video interface of the television set, the first circuit also being operable to receive control instructions from the network and/or from a user interface and to generate a generic control signal therefrom, the control system further comprising a second circuit provided on at least one second circuit board that is specific to the type of the television set, the second circuit being operable to receive the generic control signal from the first circuit and to convert the generic control signal into a specific control signal for supply to a control interface of the television set so as to control the television set in accordance with the control instructions.
Accordingly, the only part of the control system that needs to be specific to the particular television set is the second circuit board, and a single design can be employed for the first circuit board, whatever the type of television with which it is to be used.
In one embodiment, the second circuit board is installed in a slot on a main circuit board of the television set inside the housing of the television set, and the first circuit board is installed inside a housing distinct from the television set housing. In another embodiment, the first circuit board and the second circuit board are installed in first and second slots, respectively, on a main circuit board of the television set inside the housing of the television set. In a further embodiment, the second circuit board is installed in a first slot on a main circuit board of the television set inside the housing of the television set, and the first circuit board is installed in a second slot on the second circuit board or one of the second circuit boards.
A further aspect of the invention provides a combination of a first circuit on at least one first circuit board and a second circuit on at least one second circuit board for controlling a television set, the first circuit having means for receiving a digital video signal from a network (for example a receiver) and for decoding the digital video signal to produce a decoded video signal for supply to a standard video interface of the television set, the first circuit further comprising means for receiving control instructions from the network and/or from a user interface and for generating a generic control signal (for example a processor) therefrom, the second circuit having means (for example, a processor) for receiving the generic control signal from the first circuit and for converting the generic control signal into a specific control signal having a different format than the generic control signal, for supply to a control interface of a television set so as to control the television set in accordance with the control instructions.
Preferably, both the first circuit board and the second circuit board have means for installation in respective first and second slots on a main circuit board of the television set. Preferably, the second circuit board has means (for example a connector) for installation in a first slot on a main circuit board of the television set, and the first circuit board has means (for example a connector) for installation in a second slot on the first circuit board or one of the first circuit boards.
A further aspect of the invention provides a combination of a first circuit on at least one first circuit board and a second circuit on at least one second circuit board for controlling a television set, the first circuit having a first receiver for receiving a digital video signal from a network and for decoding the digital video signal to produce a decoded video signal for supply to a standard video interface of the television set, the first circuit further comprising a processor for receiving control instructions from the network and/or from a user interface and for generating a generic control signal therefrom, the second circuit having a second receiver for receiving the generic control signal from the first circuit and for converting the generic control signal into a specific control signal having a different format than the generic control signal, for supply to a control interface of a television set so as to control the television set in accordance with the control instructions.
The invention further provides a range of circuit boards for controlling a television set, each circuit board of the range comprising means for connection to a generic circuit board, each circuit board of the range comprising means (for example, a receiver) for receiving a generic control signal, based on control instructions received from a network and/or from a user interface, from the generic circuit board, and means (for example a processor) for converting the generic control signal into a specific control signal having a different format than the generic control signal, and means (for example a transmitter) for supplying the specific control signals to a control interface of the television set so as to control the television set in accordance with the control instructions.
Preferably, the formats of the specific control signals are all different for different control boards of the range. Preferably, each circuit board of the range has a slot for installation of the generic circuit board therein.
Another aspect of the invention provides a range of circuit boards for controlling a television set, each circuit board of the range comprising a connection to a generic circuit board, each circuit board of the range comprising a receiver for receiving a generic control signal, based on control instructions received from a network and/or from a user interface, from the generic circuit board, and a processor for converting the generic control signal into a specific control signal having a different format than the generic control signal, and for supplying the specific control signals to a control interface of the television set so as to control the television set in accordance with the control instructions.
Another aspect of the invention provides a method of configuring such a control system for a particular television set, the method comprising selecting, from a collection of such second circuit boards for different types of television sets, a circuit board that is specific to the type of the particular television set, and installing the selected second circuit board in conjunction with such a first circuit board.
In the case where a control system such as described above is movable, there is a problem especially in a hotel environment that a guest may take the control system from another (hotel) room to use in their own (hotel) room, for example because the control system in their own (hotel) room is not functioning properly, or so as to obtain programs or other services to which they are not entitled or for which they wish to avoid paying. As a result, the other room is left without a control system and/or the hotel may lose revenue.
An attempt to deal with a related problem is described in patent document U.S. Pat. No. 5,455,619. Each control system is connected to the network by a wall box which includes an address tag, and the control system reads the address of the address tag when it is powered up, stores it in non-volatile memory and supplies it to the server. If the address which is read when the control system is subsequently powered up is different, it is assumed that the control system and guest have moved to a new room, and so the guest continues to be billed for the service provided in the new room. The system is therefore geared to keeping track of the authorized movement of such control systems from one room to another.
To deal with the problem of unauthorized movement of a device from one place to another, another aspect of the invention provides a networked system comprising a server and a plurality of devices connected to the server by a network, the network including, adjacent each device, a releasable connector having a first connector part connected to the respective device and a second connector part connected to the remainder of the network, each device having a respective device address, each second connector part having a respective connector address, the server storing the device addresses and, for each device address a corresponding connector address, and each device being operable to: (a) supply its device address to the server and request the corresponding connector address, (b) receive the corresponding connector address from the server, (c) request the connector address from the respective connector, (d) receive the connector address from the connector, (e) compare the connector addresses received from the server and the connector, and (f) perform different processes in dependence upon whether or not the compared addresses match.
Preferably, each device is operable to (a) supply its device address to the server and request the corresponding connector address, (b) receive the corresponding connector address from the server, (c) request the connector address from the respective connector, (d) receive the connector address from the connector, (e) compare the connector addresses received from the server and the connector, and (f) perform different processes in dependence upon whether or not the compared addresses match, upon powering-up of the device, and, for example, if the compared addresses do match, to power-up to a fully-operational state, and, if the compared addresses do not match, to power-up to a partly-operational state, or “safe mode”. Each device is preferably also operable, if the compared addresses do not match, to notify the server that the compared addresses do not match.
Another aspect of the invention provides a networked system comprising a server and a plurality of devices connected to the server by a network, the network including, adjacent each device, a releasable connector having a first connector part connected to the respective device and a second connector part connected to the remainder of the network, each device having a respective connector address, the system comprising means (such as a memory, for example a solid state storage device) for storing the device addresses and, for each device address, a corresponding connector address, and means (for example a processor) for comparing, for a given device address, whether the stored corresponding connector address matches the connector address of the second connector part adjacent the device, the system being arranged to perform different processes depending on the result of the comparison. Preferably the comparing means forms part of the server.
A further aspect of the invention provides a networked system comprising a server and a plurality of devices connected to the server by a network, the network including, adjacent each device, a releasable connector having a first connector part connected to the respective device and a second connector part connected to the remainder of the network, each device having a respective connector address, the system comprising means (such as a memory, for example a solid state memory device) for storing the device addresses and, for each device address, a corresponding connector address, and means (such as a processor) for comparing, for a given second connector part, whether the stored corresponding device address matches the device address of the device adjacent the second connector part, the system being arranged to perform different processes depending on the result of the comparison. Preferably the comparing means forms part of the server.
Another aspect of the invention provides a corresponding method of operation of a device in a networked system comprising a server and a plurality of such devices connected to the server by a network, the network including, adjacent each device, a releasable connector having a first connector part connected to the respective device and a second connector part connected to the remainder of the network, each device having a respective device address, each second connector part having a respective connector address, and the server storing the device addresses and, for each device address a corresponding connector address, the method comprising (a) the device supplying its device address to the server and requesting the corresponding connector address, (b) the device receiving the corresponding connector address from the server, (c) the device requesting the connector address from the respective connector, (d) the device receiving the connector address from the connector, (e) the device comparing the connector addresses received from the server and the connector, and (f) the device performing different processes in dependence upon whether or not the compared addresses match.
In a further aspect the invention provides a method of operation of a networked system comprising a server and a plurality of devices connected to the server by a network, the network including, adjacent each device, a releasable connector having a first connector part connected to the respective device and a second connector part connected to the remainder of the network, each device having a respective connector address, the method comprising (a) storing pairs of addresses, wherein each pair comprises a device address and a corresponding connector address, (b) comparing, for a given device address, whether the stored corresponding connector address matches the connector address of the second connector part adjacent the device, and (c) performing different processes depending on the result of the comparison.
In a further aspect, the invention provides a method of operation of a networked system comprising a server and a plurality of devices connected to the server by a network, the network including, adjacent each device, a releasable connector having a first connector part connected to the respective device and a second connector part connected to the remainder of the network, each device having a respective device address, the method comprising (a) storing pairs of addresses, wherein each pair comprises a device address and a corresponding connector address, (b) comparing, for a given second connector part, whether the stored corresponding device address matches the device address of the device adjacent the second connector part, and (c) performing different processes depending on the result of the comparison.
Preferably, with regard to the latter two aspects of the invention, the addresses are compared by the server.
Preferably, the device comprises means (for example a power-up controller) for performing said (a) to (c) upon powering-up, and the device has means (for instance a power control circuit) for powering-up to a fully-operational state if the compared addresses do match. Preferably, the device may have means (for instance a power control circuit) for powering-up to a partly-operational state if the compared addresses do not match. Further, the device preferably has means (such as an output device) for notifying the server that the compared addresses do not match if the compared addresses do not match.
In a further aspect, the invention provides a device for use in a networked system comprising a server and a plurality of such devices connectable to the server by a network via respective connectors, the device having a respective device address, the device comprising (a) means (such as an output device) for supplying its device address to the server and requesting a corresponding connector address stored in the server, (b) means (such as a receiver) for receiving the corresponding connector address from the server, (c) means (such as an output device) for requesting the connector address from a connector for the device, (d) means (such as a receiver) for receiving the connector address from the respective connector, (e) means (such as a processor, for example a comparator) for comparing the connector addresses received from the server and the connector, and (f) means (for example a processor) for performing different processes in dependence upon whether or not the compared addresses match.
Preferably, the device comprises means for performing the functionality of the elements (a) to (f) upon powering up.
In a further aspect the invention provides a device for use in a networked system comprising a server and a plurality of such devices connectable to the server by a network via respective connectors, the device having a respective device address, the device comprising (a) an transmitter for supplying its device address to the server and requesting a corresponding connector address stored in the server, (b) a receiver for receiving the corresponding connector address from the server, (c) an output device for requesting the connector address from a connector for the device, (d) an input device for receiving the connector address from the respective connector, (e) a comparator for comparing the connector addresses received from the server and the connector, and (f) a processor for performing different processes in dependence upon whether or not the compared addresses match.
Features of any aspect of the invention may be combined with or interchanged with features of any other aspect as desired. Method features may be applied to apparatus aspects and vice versa. Features which are provided independently may be provided dependently, and vice versa.
Preferred embodiments of the invention will now be described, purely by way of example, with reference to the accompanying drawings in which:
Referring to
There are a number of problems or disadvantages with a conventional distribution system as described above with reference to
In order to deal with these problems and disadvantages, the embodiment of the invention that will now be described with reference to
The network 50 is designed to support a bandwidth of up to 10 Mbps for communication between the server 56 and each LCU 66. The components required to deliver this bandwidth will vary because of the different topology of each hotel-for example, the layout of floors, risers, and the location of the equipment room 16 in which the server(s) 56 is/are situated.
The required bandwidth of 10 Mbps per LCU 66 can be delivered using a switched network built on one or more high speed (100 Mbps) switches 68 each having up to twenty three ports, for instance eleven ports, that are in turn linked to the server(s) 56 (and to each other) via a Gigabit switch or high speed backbone network linking switches 70. Each LCU 66 is connected to the network via such a 100 Mbps switch 68 and a Category 5 (ANSI/EIA/TIA-568-1991) unshielded twisted pair (UTP) cabling system 72 operating at up to 10 Mbps. Each switch 68 is connected to the backbone 74 using such a Gigabit switch 70 and a Category 5 UTP cabling system 76 operating at up to 100 Mbps. The server(s) 56 is/are connected directly to the Gigabit switch 70.
This architecture can be simplified for smaller installations that do not have high bandwidth requirements, by using 10/100 Mbps switches with fewer ports, and by using a lower speed cabling system for the backbone network.
The embodiment described above using Category 5 UTP cabling is efficient, scalable, manageable and cost-effective. It also uses many established components and widely available skills. From the network management perspective, this option is the most controllable and the easiest architecture on which to build other applications. However, the installation of the cabling 72,76 and switches 68 is disruptive and so installation into an existing hotel will make hotel rooms unavailable for a substantial period of time, which may be unacceptable to the hotel's owners. For this reason, this option may only be suitable for new hotels and the refurbishment of existing hotels.
To deal with this problem, the required bandwidth of 10 Mbps per LCU 10 can also be delivered using the RG59 baseband coaxial cable infrastructure 38 as shown in
Low grade coaxial cable is traditionally used to supply analogue video to hotel rooms. Each television signal occupies a 6 MHz bandwidth. The coaxial cable has a typical bandwidth of 460 MHz, which allows up to 76 television channels to be frequency multiplexed together and carried by the one cable network.
The losses over a 75Ω RG59 television coaxial cable are typically 0.13 dB/m at 100 MHz, 0.19 dB/m at 200 MHz and 0.46 dB/m at 100 GHz. Such coaxial cable can be used without modification to carry digitally encoded MPEG video. Using digital encoding, each analogue channel is transformed to a “data pipe” with over 30 Mbps of capacity. This pipe is used to carry a multiplex of video channels. The number of video channels that can be carried depends on the picture quality required. For received PAL TV picture quality, typically six video channels can be carried in each pipe.
The lowest frequency channel is used as a “back channel” to feed low data rate information from individual rooms back to the server 56. The back channel is operating at a much lower data rate and can withstand much worse signal-to-noise ratios than the wide-band analogue television signals. Therefore, the system can cope with the additional losses introduced by the return path on top of the losses from any distribution amplifiers used.
Digital video over coax generally uses a 64QAM modulation scheme, where groups of 6 bits are mapped to a carrier state. Each carrier state has a unique amplitude/carrier phase position as illustrated in
In order to decode 64QAM with an acceptable worst case error rate, before error correction, of 1 error in 104 bits, a signal-to-noise ratio per bit of greater than 18 dB is needed. At a smaller signal-to-noise ratio each dot in the constellation will become blurred and it will not be possible to differentiate one dot from another. A 1.5 dB difference in signal-to-noise level will make an order of magnitude difference in the error rate.
Higher order QAM schemes can be used to increase the data capacity of each channel. The increased capacity is gained at the price of needing a higher signal-to-noise ratio to properly decode the signal. Conversely, lower order schemes are more rugged but have a lower capacity.
MPEG compressed video and audio is sensitive to errors. A final error ratio of near 1 in 1010 is needed for good quality pictures. Forward error correction schemes are used to correct errors in the raw data stream to achieve the required error rate. The signal-to-noise ratios needed to demodulate 64QAM to obtain good quality MPEG encoded video are slightly less than that needed to receive an analogue TV channel. A major difference though, is that if the signal-to-noise ratio of the 64QAM signal degrades below the minimum required the picture rapidly degrades and is easily lost. With analogue TV the signal degradation is much more graceful. The signal-to-noise ratio of the transmitted signal will be much higher than that required for successful demodulation and decoding of the MPEG video. However, the coax network will degrade the signal. It will attenuate the signal, and noise will be introduced into the system by:
Amplifiers-all amplifiers are not perfect and introduce some noise. The signal-to-noise ratio will be degraded by the noise figure of the amplifier, typically 3 to 5 dB
Ingress into the cable system from other RF transmissions and other electrical noise.
Maximum signal levels will be determined by the maximum practical levels any amplifiers can amplify to whilst maintaining their linearity (if the amplifiers compress, the outer points in the constellation will not be in the correct position) and regulatory EMC limits.
The existing coaxial cable infrastructure has a wide bandwidth and could be used for digital multimedia applications. When considering their suitability for a multimedia system a number of factors should be considered:
Possible coax-based approaches include:
Of these coax-based approaches, the second is preferred.
Across conventional hotel television infrastructures, each program is broadcast in analogue format on a separate channel within the coaxial cable 40, as already described with reference to
As illustrated schematically in
The repartitioning of the channels on the coaxial cabling 40 is achieved by installing a cable modem termination system 80 between the server 56 and the coaxial cable network 38, and a cable modem 82 in each LCU 66. As shown in
It should be noted, in the system described with reference to
Although it is known to use two-way amplifiers 44 in coaxial distribution systems as described with reference to
A number of digital television standards have been adopted by residential cable television suppliers. These standards typically allow for one or more of the 6 MHz down-link channels to carry IP traffic at 27 Mbps. Up-links operate at typically between 500 Kbps and 10 Mbps. A number of open and proprietary standards exist. Open standards include:
In order to deal with the problem of disruption if installing a new network into an existing hotel, the required bandwidth of 10 Mbps per LCU can also be delivered using the telephone cable infrastructure within the hotel 10.
As shown in
While this type of cable (Category 2) is of inferior quality to the standard network cable (Category 5) used in business offices, the cable can be used for the transmission of data in a controlled environment-such as the hotel 10, as shown in
Traditional analogue telephone operates in the frequency band 300 to 3.3 KHz. The twisted pair cable 92 does not have as wide a bandwidth as coaxial cable but the bandwidth is significantly wider for digital signals than the hand used for analogue telephony. The actual bandwidth of data the cable can support depends on the distance it needs to be transmitted and the degree of interference or cross talk it is subjected to. For the typical cable distances in a hotel of say 100 m, a data rate of up to 25 Mbps may be achieved in one direction. This is adequate for carrying an MPEG-2 encoded television channel.
As twisted pair cables tend to be run in bundles, cross talk between twisted pairs, rather than attenuation of the signal, tends to be the limiting factor affecting operating distances. Cross talk can be divided into two different categories, NEXT (Near End Cross Talk) and FEXT (Far End Cross Talk).
The difference between NEXT and FEXT and the consequences of the two effects can be understood by considering two twisted pairs bundled together going into a PABX:
As the system of
Factors to consider for using the existing hotel telephone network for a multimedia system include:
Two standards utilizing standard twisted pair telephone wires are possibly applicable to the embodiment of
ADSL (Asymmetric Digital Subscriber Line) was originally proposed for video-on-demand applications over the ‘local loop’ between the telephone exchange and home. More recently, it has been used for high speed internet access over the same local loop. Both applications need higher down-link data rates than up-link data rates and so are suitable for an ‘asymmetric’ standard i.e. a higher down-link bandwidth relative to up-link bandwidth. This also minimizes the problems of NEXT described above. ADSL typically has a range of downstream speeds depending on the distance. This includes 8.448 Mbps at distances of up to 2750 meters. Up-stream data rates range from 16 Kbps to 640 Kbps depending on application and individual product implementations. The standard is designed to operate at the same time as standard analogue telephone equipment. It does this by operating in the frequency range of 25 KHz to 1 MHz, leaving the lower frequency portion clear for standard telephone. As equipment using the standard is being deployed by a large number of telecommunications operators, both head end equipment suitable for many subscribers and consumer modem/set top boxes are available. As ADSL is designed for point to point links only, the splitters 98,102 will probably be needed, placed at both the head end and at the entrance to the hotel room. Their function is to ensure that additional lines going to the hotel PABX 90 or room telephone 88 do not form part of the ADSL network. Noise induced onto telephone lines tends to have a “bursty” nature. This badly affects real time services such as video by wiping out a block of data which error correction schemes find impossible to correct. In a real time system, there is no chance to retransmit the data as there is in data communication systems. To overcome this problem, ADSL interleaves blocks of data so that the errors caused by the noise burst become distributed “white” noise which causes occasional bit errors. These errors may then be rectified by standard error correction schemes, or may not need correction at all, as they are spread across the picture and so are not noticeable to the viewer. There is little doubt that ADSL is suitable for multimedia applications in hotels, but it may be considered over-specified for the task and so may be more expensive than necessary.
Home PNA is an alliance of over one hundred manufacturers who have devised a computer networking standard using the telephone cable network found in domestic homes. The alliance includes many large manufacturers such as IBM, 3COM and Intel. To access the standard, companies have to become an adopter member of the alliance. Two versions of the standard exist. The first is designed to operate at 1 Mbps, which is clearly too slow for video, but may be suitable for other parts of the hotel system. The second operates at 10 Mbps, which is more suitable. The technology is designed to operate concurrently with telephone and xDSL. It does this by operating at higher frequencies than either of these two technologies. As the standard is designed for applications in homes, a wide range of equipment is available for domestic applications at low cost. This equipment would be suitable for use in hotel rooms.
It is clear that the coaxial solution of
Of the methods for providing a network discussed above, clearly Category 5 cabling (
The heart of the system within the hotel room is the LCU 66, which acts as an interface between the guest and the server 56. Some of the functions of the LCU 66 are similar to set top boxes (STB) used to access broadcast digital television signals, and the LCU 66 can therefore utilize many of the components designed for these devices. The LCU 66 may be provided in a box separate from the television 14, or it may be physically located inside the television set 14. A major difference between the LCU 66 and a conventional STB is that the down-link data will be specific to that box and not broadcast. This means that there is no requirement for user-adjustable “tuner” circuitry found in conventional STBs, as the LCU 66 will in effect be “tuned” to one fixed channel, and the server 56 will ensure that the correct data is transmitted on that channel.
The LCU 66 is able to control the functions of the television 14, via a proprietary control interface circuit 114, so that the guest can use a single remote control unit 110 to adjust television parameters such as volume, brightness, color etc. Additionally, this interface circuit 114 allows the server 56 to control the television 14 so as to display the time and turn on the television 14 for alarm calls, welcome messages, etc. One requirement for the LCU 66 is that it should not be proprietary to any one make of television, so a mixture of a generic card 116 (carrying the STB chip set 118, network interface circuit 104, etc.), software configurability and one or more daughter cards, such as the television control interface circuit 114, are used to overcome the problem of different proprietary interfaces to different makes of television sets.
Three different types of data are sent from the server 56 to the LCU 66, all of which enter the LCU 66 via the network interface circuit 104:
A central processor (CPU) 120 interprets commands directly, while other user data may, for example, be converted to graphical images by application software running on the CPU 120. The graphical image is built up in a frame buffer that is part of the video encoder circuitry 122. The digital video stream from the server 56, which is compressed using MPEG-2 compression techniques, is passed to an MPEG decoder 124 where it is converted to graphical images, which are also passed into the frame buffer in the video encoder 122. Unlike conventional STBs, the LCU 66 will not need to handle MPEG transport de-multiplexing and de-scrambling, since these functions are handled by the server 56. The LCU 66 will receive a single unscrambled MPEG stream. The video encoder 122 takes the bitmap image in the frame buffer and produces the analogue signals 112 that are passed to the television set. These signals 112 can be in various different standard formats such as RGB, CVBS and S/VHS. If possible, RGB is the preferred option as it gives the best picture quality (using the television set 14 as a monitor). However, not all television sets 14 can support this format of input, so an alternate such as CVBS (also known as “composite video”) is also supported.
One of the requirement for the video encoder circuit 122 is to be able to generate pictures in either PAL or NTSC formats, as there is no single world standard (generally Europe uses PAL and the U.S. uses NTSC). The French SECAM standard probably need not be supported, as a PAL system could be used instead.
One final task which the video encoder 122 may perform is to add Macrovision copy protection encoding. This alters the synchronization signals in such a way as to make recordings unviewable without altering the picture when viewed on the television 14. Use of this technology is often required when films are made available for presentation on a pay-per-view basis prior to their general release on video. Because of the way in which Macrovision works, the RGB output has to be disabled, so when enabled, the CVBS or S/VHS outputs will need to be used.
Audio signals are either extracted from the MPEG stream or created by the processor 120 (i.e. from a “.wav” file or other streaming audio source) and converted to stereo analogue signals using a digital to analogue coder/decoder. Some chipsets now offer Dolby Digital audio decoding as well as standard MPEG decoding.
In the case of a requirement for the LCU 66 to run the application software with complex graphics, the CPU 120 is preferably based on a powerful 32-bit core. To enable the MPEG stream to be decoded, a minimum of 2 Mbytes of SDRAM are required, but most chip-sets 108 would require another 2 Mbyte for processor applications. Use of a unified memory architecture removes the need for VRAM, by placing the frame buffer in the SDRAM. Additional hardware is also often included to render the images so that they do not “flicker” when displayed on the television 14.
All the application code, and the operating system code, is stored in Flash memory 126, so that the code can be upgraded. The memory controller to drive the SDRAM and Flash memory 126 is included on-chip, along with various peripheral controllers to interface to the EEPROM 128 and other devices. The IBM STB03xxx chip-set may be used for the LCU 66.
In view of the desire to install the system in an existing hotel 10 having existing television sets 14, it is desirable that the LCU 66 be able to connect to a diverse range of television sets without the need for manufacturing too many permutations of the LCU 66. There are two ways of addressing this requirement:
When the generic card 116 of the LCU 66 is provided in a stand-alone box 130, as shown in
However, the casing for the stand-alone box 130 will in itself be a discrete cost, and different casings will also have to be manufactured for each model of television 14 if the casing is to be attached to the base of the television 14. Servicing will also be more difficult, as the system will comprise two physically separate components rather than a single integrated unit. There are also issues surrounding the security of the stand-alone box 130 and the potential maintenance issues raised when guests “tamper” with the stand-alone boxes 130.
Apart from the obvious aesthetic advantage, mounting the LCU 66 inside the television 14, as shown in
Many of the issues raised by providing the LCU as a stand-alone box can be negated by incorporating the LCU 66 within the television set 14. There is also a significant cost saving from not having to manufacture the casings for the stand-alone boxes. However, to incorporate the LCU 66 within the television set 14 as shown in
While new television sets are built with chassis that support interface cards, older sets may not, so the manufacture of stand-alone boxes 130 may be unavoidable if all situations are to be covered.
Off-the-shelf software products may be used in the LCU 66, including a real-time operating system (RTOS), such as RTOS Red Hat Linux and system software bundled with Red Hat Linux. The chosen RTOS should provide support for the chosen chip-set and the ability to control streaming video. Any chosen RTOS should also support a TCP/IP stack and drivers for the network interface circuit 104. The RTOS controlling the LCU 66 may also provide several auxiliary services, such as:
Code to control the low-level functionality of the chip sets 118 is best obtained directly from the chip-set manufacturer's reference design. If this can be done it means that the only code that needs to be newly written would be the top-level user interface.
Referring now to
In addition to the features described with reference to
The Category 5 cable 72 leading to each room 12 is connected to a wall box 142 having a conventional RJ45 socket 144 to which the network interface circuit 104 of the LCU 66 is connected by a Category 5 patch cable having an RJ45 plug 148. An address processor circuit 150 is contained in the wall box 142 and includes non-volatile memory 152 storing a unique address for the wall box 142. The address processor 150 is operable to respond to a request from the LCU 66 by returning the stored wall box address to the LCU 66.
When the system is installed, the system server 56 is set up to store a list of the addresses of all of the wall boxes 142 in the hotel, and when each LCU 66 is installed in a room 12, the address of the LCU 66 is stored in the list on the server 56 against the wall box address for that room 12.
The CPU 120 in each LCU is programmed to perform the boot processes illustrated in
It will therefore be appreciated that an LCU 66 will not fully boot unless it is connected to the wall box 142 designated for that LCU 66 in the list stored on the server 56.
Although the address processor 150 has been described above as being incorporated in a wall box 142 in the particular room 12, it should be noted that other locations are possible, such as at the room ports of the switches 68 in
It should be noted that a similar development may be made to the systems employing coaxial cable or telephone cable.
The server 56 will now be described in more detail, also with reference to
The server 56 processes these input streams in a variety of formats (analogue, digital, compressed, encrypted, etc.) and outputs digital streams in MPEG-2 format to the switch 70 that supports Internet Group Management Protocol (IGMP). A channel controller uses IGMP to allow LCUs 66 to subscribe to any of the shared stream-based media services. The UDP/IP transport protocol is used for transmitting MPEG-2 streams to the LCU 66.
The server 56 comprises media capture, compression, and streaming functions and includes a media manager 174 that handles media-related events. The media manager 174 collects channel and schedule information from a configuration manager 176 and then passes messages to a specific channel manager 178. These messages detail actions that need to be taken; for example, loading an asset file, or streaming an asset on a particular card/channel. The configuration manager 176 holds a central repository of system-wide information. This data is used to control many aspects of a particular installation. A subset of the configuration manager database holds information specific to the server 56. This identifies the various servers, the cards that are registered, the channels that have been assigned, the loaded media assets and the overall schedule.
The server architecture supports both live and stored audio and video delivery. Live feeds are converted using specialized digitizer boards, compressed using hardware codecs, split into packets, and encapsulated inside an application transport protocol before final delivery on the network. Stored media files may be held in a compressed format in the media repository. These are loaded locally on the server 56 and are delivered in a similar manner on a scheduled basis.
The system supports the delivery of terrestrial television and radio, satellite television and pre-digitized media streams. Analogue streams, such as local television and radio channels, are captured and compressed prior to distribution. The delivery of analogue or digital television and radio requires efficient data capture and compression. This capability is available through hardware video and audio capture cards 180-184. These cards allow the capture of a variety of analogue and digital streams from television and radio, and the generation of digital streams in MPEG-2 format for video, or MP3 format for audio. However, these cards operate on one specific input channel, and so a single card is provided per channel. The MPEG-2 or MP3 stream that is generated by each card is routed directly to an address and port on the network.
Referring also to
The card 182 used for an analogue terrestrial television channel is shown in
Turning now to the processing that is performed to convert the analogue radio frequency signals on which satellite channels are delivered to the hotel via satellite dish 22 into digital streams in MPEG-2 format, ideally the analogue satellite card 188 (
One card 180,188 will be installed in the server 56 per satellite channel that the hotel wants to receive. The server 56 uses a DHCP client to request IP addresses for each card 180,188 installed. Each card 180,188 supports an SNMP client that reports any change in the status of the card to the SNMP server. The input port 194,204 of the first card is connected to the coaxial cable from the satellite dish. Additional cards can be added as required to the server 56. Where multiple cards are deployed a distribution amplifier is used to ensure that a consistent source signal strength is available to all cards. A hardware failure on one card will not affect the functioning of other cards. The listening frequency of the demodulator on each analogue satellite receiver card 180,188 will be under software control. The descrambling algorithms will also be under software control, if possible. The table below tracks the path of the stream sequentially through the analogue satellite receiver card 188, starting at the satellite dish 22 and terminating at the RJ45 output port 192 on the card 188.
Turning now to the processing that is performed to convert analogue frequency signals on which local radio is delivered to the hotel via a roof-top aerial 216 into digital streams in MPEG-2 format, one card 184 (see also
In the case of the reception of digital satellite television, a card 190 (
The play-out cards 186 that store MPEG-2 files on the server 56 and stream these files within the hotel will now be described, also with reference to
The server 56 is configured with the following components: three or more 18 GB (min.) wide SCSI hard disk drives 234; a RAID 5 disk controller card 236; and a 100BaseT network card 238.
When the media manager 174 notifies the channel manager on the server 56 to start playing a particular media asset (film) it instructs the play-out card 186 to load and process a local copy of the file and stream this direct through its 100 BaseT network port 192. This will in turn connect to the IGMP switch 70, so that LCUs 66 associated with the appropriate IGMP group will receive the MPEG-2 stream. The local disk array 234 holds the required films as MPEG-2 format files. The server 56 uses a DHCP client to request IP addresses for each network component installed. Each card supports an SNMP client that reports any change in the status of the card to the SNMP server. The following parameters will be under software control; the full filename and path for the media assets; the channels associated with each card; and the asset to be streamed on a particular channel. The table below tracks the path of the stream sequentially through the server when the asset is played.
In any or all of the aforementioned, certain features of the present invention have been implemented using computer software. However, it will of course be clear to the skilled man that any of these features may be implemented using hardware or a combination of hardware and software. Furthermore, it will be readily understood that the functions performed by the hardware, the computer software, and such like are performed on or using electrical and like signals.
Features which relate to the storage of information may be implemented by suitable memory locations or stores. Features which relate to the processing of information may be implemented by a suitable processor or control means, either in software or in hardware or in a combination of the two.
Analogous method steps to the apparatus features described herein are provided within the scope of the invention, and vice versa. In any or all of the aforementioned, different features and aspects described above, including method and apparatus features and aspects, may be combined in any appropriate fashion.
It will be understood that the present invention(s) has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.
Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/GB01/00533 | Feb 2001 | GB | national |
This application is a continuation of application Ser. No. 09/958,881 filed Mar. 19, 2002.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09958881 | Mar 2002 | US |
| Child | 13231542 | US |
