Audio/video signal redistribution system

AUDIO / VIDEO SIGNAL REDISTRIBUTION SYSTEM

FIELD OF THE INVENTION

The present invention relates to communication systems, and more specifically to interoperable audio / video telecommunication systems that integrate audio / video signals received in many formats and redistribute them to many users via existing telephone wires.

BACKGROUND OF THE INVENTION

Modern society is heavily dependent on many different types of audio / video telecommunication services that affect all aspects of daily life. Television is one of the most popular sources of information and entertainment. Other sources of information and entertainment include computer networks, such as the Internet, which nowadays offers shopping, banking, gaming, discussion and social networking, as well as many other products and services, home video games, video tape rental and the like. These types of services represent a virtually unlimited variety of information and entertainment for virtually every corner of the globe.

However, these services have evolved independently for decades and are therefore made in different formats and distributed through incompatible channels. For example, television signals may be received through an antenna, cable distribution network (CATV) and satellite broadcasting, but access to each type of these signals is independent of the others and requires specialized equipment and / or operator. A television set may be equipped to receive signals from all these sources, but only one at a time, so that some kind of switching equipment on the receiving side is required to change the source of the reception. Furthermore, each of these signals inherently has many channels, complicating attempts to integrate all services into a single system. The Internet is accessible via modem via CATV or telephone wires, but is typically connected to a computer, which is a completely separate viewing system.

Prior to the invention, there was never a system available to integrate these types of services that would allow the user instant access to any channel provided by any telecommunications or radio broadcasting operator using a single system. Moreover, prior to the invention, there was no affordable system for joint operation that it was

-2 Easy to use and would transmit any telecommunication or radio broadcasting service over a single wiring.

Content of the invention

The present invention avoids these disadvantages by providing an interoperable audio / video redistribution system that integrates the various available broadcast and telecommunications services by integrating these services into a single system that redistributes audio / video signals received in many formats, and distributes it to many users. The invention allows the user to remotely select and control the source of the audio / video signal they want to watch or have access to. At the same time, it provides access to any radio or telecommunication system through a single receiving unit, which is preferably a television receiver. It further provides the invention with an interoperable system that is easy to manage and enables the user to use reciprocal services such as those accessible via the Internet. Furthermore, the invention can be introduced via existing telephone wires, which significantly reduces the cost of the system and thus provides easy and inexpensive installation of the system.

The system achieves this by providing a redistribution device so equipped to receive telecommunication signals in any format and then redistribute the selected signals to the user site. The redistribution device is in communication with an interface located with the user and receives command signals input from the user using a conventional infrared (IR) remote control in a preferred embodiment of the invention. The redistribution device comprises a switching circuit that directs the selected signal to a user location where it is received by a receiving unit, preferably a television set. A single redistribution device supplies the entire network of multiple users from a common distribution point in normal telephone wiring, with multiple users independent of each other. Moreover, the system according to the invention does not interfere with the normal use of the telephone network, so that users can simultaneously use the services of the system and use the telephone or any existing antenna or CATV network, so that users also have the opportunity to receive services through these networks.

Each user can choose to access a telecommunication system or program from a user-driven menu interface that can provide many levels of submenus with options specific to the individual telecommunication services the user chooses.

-3User network users can thus instantly and independently access any available telecommunication service, regardless of the input signal format.

In a preferred embodiment, the system of the invention is provided with a prohibition of parental control channels, a signal processor that prevents the received programs from being recorded on video tape, a magnetic card reader or some other access control method, a system log that records all activities and user access to billing services within the network, with system overrides allowing the system operator, to deny access to certain services to certain users or to allow the operator to redistribute selected programs (such as an emergency message in an emergency) and with other features that will become clear from the following description.

The present invention thus provides a system for redistributing a plurality of audio / video signals to a plurality of communication interfaces through the conductors and comprising a server, a redistributor for receiving a plurality of input signals, comprising for each input signal a demodulator for demodulating the signal, wherein the server controls the selection of the output channel relative to one or multiple command signals input to the communication interface, for each communication interface a switching device for directing the selected channel to the redistributor output, the switching device being controlled by a server responding to one or more command signals input to the communication interface and for each demodulated input signal a processor processing the switching signal at whereby the communication interface accepts the output of the redistributor for transmission to a receiving unit connected to the communication interface.

The present invention further provides a method for redistributing a plurality of audio / video signals to a plurality of communication interfaces via conductors, comprising the steps of receiving a plurality of input signals from a signal redistributor, which demodulates each input signal and converts it into a format suitable for switching, switching the output of the redistributor Depending on one or more command signals input to the communication interface and directing the redistributor output to the communication interface, wherein the redistributor output accepts a communication interface for transmission to the receiving device.

Brief description of the drawings

The drawings merely illustrate, by way of example, a preferred embodiment of the invention.

-4Figure 1 is a block diagram of a redistributor of the invention.

Figure 2 is a block diagram of a communication interface for a redistributor of Figure 1, and

Figure 3 is a schematic representation of the user interface.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, the invention comprises a redistributor 8 and a communication interface 100. The redistributor 8 is used as a telecommunications signal receiver and router / redistributor. It receives a multitude of audio / video input signals and redistributes selected signals from users to many users from a common distribution point of telephone wiring on a multi-user site. The communication interface 100 is installed in each unit and sends the selected input signal from the redistributor to the receiving device 2, which is in the preferred embodiment a conventional television set, and receives input command signals from the user, which transmits it to the redistributor 8 for selecting the input signal and for each other communication where the selected input allows it. The use of the term audio / video signals refers to all telecommunications and radio broadcast signals containing audio information or video information, or both.

Redistributor 8 receives signals in many formats, processes the signals, and redistributes the selected channel to the user based on the commands it receives from the communication interface 100. Command signals are transmitted to the redistributor 8, which distributes the signals to the users via the leads that are preferred in the telephone pair 1.

In rare cases where an existing telephone wiring is inappropriate, for example, consisting of a single-pair cable, wiring with a suitable number of pairs for the system of the invention may be installed or ground may be used as a total mass to guide redistribution and command signals, with allowing the system to operate efficiently via a single telephone pair, as will be described in more detail below. In new buildings where the system according to the invention is already under construction, it is best to install an eight-pair cable (instead of two or four-pair cables) to optimize the benefits of the invention, which includes supplying multiple 2 V TVs to each user unit as described below.

-5Redistributor 8 is installed on a multi-user site, such as an apartment or a residential neighborhood, a business center, a hospital, a school, a local loop in the telephone system, and the like. A multiplayer site can be any place or network that provides a common distribution point for a regular telephone cable, such as a Category 5 PSTN cable, or any other local cable wiring that is routed to individual units in the area. Existing wiring in such a multi-user area has almost always the minimum four-wire cable used, ranging from a common distribution point to individual units. Examples of multi-user areas are apartment blocks, business skyscrapers, hospitals, groups of detached houses wired in the local loop, schools (which are wired to individual classrooms via an internal telephone network) and the like.

Each input contains a demodulator and processor for a specific input signal format. The preferred embodiment of the invention shown in Figure 1 contains, as an example, different types of input signals. The system of the invention may be equipped to receive and redistribute any video or audio / video signal in any format, which includes all remote audio / video signals and local audio / video signals (such as a security camera signal in a closed system), so that the invention is not limited to the specific signal types illustrated and described below.

The antenna input 20 is adapted to receive antenna television signals over an antenna 22 adapted to receive VHF and UHF frequency bands, including FM radio frequencies. The antenna signal is received by a frequency antenna demodulator 24 with a channel, preferably compatible with at least NTSC, PAL and SECAM video formats, which processes separate audio and video signals into the baseband for input to the antenna processor 26, which further processes the switching signals, such as described below. The input frequency selection is determined by the commands provided by the user with a conventional remote control via the communication interface 100 to the server 6, which controls the cross-matrix switch 7 via the data bus A.

The CATV input 30 is adapted to receive CATV signals via a conventional coaxial cable 32. The CATV signal is received by a frequency CATV demodulator 34 having a channel adapted to receive CATV signals via sub, low, medium, hyper and super bands in interconnected carrier frequencies (IRC) ) and harmonically dependent carrier frequencies (HRC). Demodulator 34 processes separate audio and video signals into the base band for CATV input

-6processor 36 that processes signals for switching. The input frequency selection is determined by the commands provided by the user via the communication interface 100 to the server 6, which controls the cross-matrix switch 7 via the data bus A.

The DSS input 40 is adapted to receive DSS (direct from satellite) signals received by the satellite antenna 42 via a frequency DSS demodulator 44 that processes separate audio and video signals into the base band for input to the DSS processor 46. The demodulator 44 is preferably adapted for receive DSS signal in both C and KU bands independently of protocol and format with NTSC, PAL and SECAM compatible channel and receiver bandwidth of approximately 0.900 to 21.8GHz. The demodulator 44 processes separate audio and video signals into the baseband for input to the DSS processor 46, which processes the switching signals. The input frequency selection is determined by the commands provided by the user via the communication interface 100 to the server 6, which controls the cross-matrix switch via data bus A,

The MMDS input 50 is adapted to receive MMDS signals (multipoint multi-distribution system) received by the MMDS antenna 52 through a frequency MMDS demodulator 54 that processes separate audio and video signals into the baseband for input to the MMDS processor 56. The demodulator 54 is preferably adapted for MMDS reception in 2.4GHz and 22GHz bands independently of protocol and format with NTSC, PAL and SECAM compatible channel. Demodulator 54 processes separate audio and video signals into the baseband for input to the DSS processor 56, which processes the switching signals. The input frequency selection is determined by the commands provided by the user via the communication interface 100 to the server 6, which controls the cross-matrix switch 7 via the data bus A.

The MPEG input 60 is adapted to receive MPEG signals through an MPEG decoder for processing in a demodulator 64 that processes separate audio and video signals into the baseband for input to an MPEG processor 66. The demodulator 64 is preferably adapted to receive an MPEG signal in 1, 2 or 4 such as from a video server or video library. Demodulator 64 is protocol and format independent and has a NTSC, PAL, and SECAM compatible channel. Demodulator 64 processes separate audio and video signals into the baseband for input to the MPEG processor 66, which processes the switching signals. The input frequency selection is determined by the commands provided by the user via the communication interface 100 to the server 6, which controls the cross-matrix switch 7 via the data bus A.

-Graphic input 70 is adapted to receive video signals from a video source, such as a video game server 72, which is processed by a demodulator 74 that serves as a VGA or computer-generated video and audio signal to a compound converter. Text, graphical user interface navigation screens and video games are separated into audio and video signals of the baseband band for input to the GPU 76, which processes the switching signals. The input selection is determined by the commands provided by the user via the communication interface 100 to the server 6, which controls the cross-matrix switch 7 via the data bus A.

The input 80 for the Internet is adapted to receive video signals from a processing computer 82 in a demodulator 84 that serves as a VGA or computer-generated video and audio signal to a composite converter. Internet browsers and communications are not restricted by protocol or architecture. The Internet processor 86 processes the switching signals. Navigation is controlled by user-provided commands via communication interface 100 to server 6, which controls the cross-matrix switch 7 via data bus A.

The input to the closed circuit 90 is adapted to receive video signals from a closed circuit camera 92, such as a security camera, for processing in a demodulator 94 that serves as a VGA or computer-generated video and audio signal to a compound converter. The closed circuit processor 96 processes the switching signals. The switching between different cameras is determined by the commands provided by the user via the communication interface 100 to the server 6, which controls the cross-matrix switch 7 via the data bus A.

Server 6 is preferably a computer that has at least 486 microprocessors and is open platform, platform independent and scalable. Server 6 controls the flow of data back from the communication interface 100 and all demodulated inputs and manages the database as described below to provide billing, billing, account tracking and program history. Server 6 provides communication inputs for ISDN, optical fibers, satellite, PSTN, analog and digital input / output devices and / or any other desired accessory. Server 6 also serves as a router to manage and route information through the A, B, and C data buses.

Demodulator data bus B interconnects all demodulators and decoders and interfaces with server 6. Data bus B is not limited by protocol, speed, frequency, form factor or format.

-8Processors 16, 26, 36, 46, 56, 66, 76, 86 and 96 process their respective input signals in a format that can be switched by the cross-matrix switch 7 and sent to the communication interface 100 via an unshielded pair. Each of the processors 16, 26, 36, 46, 56, 66, 76, 86 and 96 adjusts the signal impedance of the output impedance; raises the basic frequency band of the demodulated signal (eg to 300kHz); equalizes high frequency components (for example at 3dB), increases color purity and increases the mean voltage (Vpp) value of the demodulated signal. Processors 16, 26, 36, 46, 56, 66, 76, 86, and 96 also convert and translate feedback command signals received by the cross-matrix switch 7 from the communication interface 100 and directed to server 6 via data bus B.

Cross Matrix Switch 7 is a multi-input switch to a single non-blocking output and is not limited by size, bandwidth, speed, form factor, protocol, architecture, or format. The received command signals are transmitted by processors 16, 26, 36, 46, 56, 66, 76, 86 and 96 to server 6, which controls the cross-matrix switch 7, and directs the selected input to the output of the cross-matrix switch 7 for transmission back to the communication interface 100. A separate cross-matrix switch 7 is provided and intended for each communication interface 100 housed at the individual units within the multiuser space.

Processor data bus C interconnects all processors 16, 26, 36, 46, 56, 66, 76, 86 and 96 and interfaces with server / router 6. Bus C is not limited by protocol, speed, frequency, form factor, or format.

Data bus A interconnects each cross-matrix switch 7 with server / router 6. Bus A is not limited by protocol, speed, frequency, form factor, or format. The output of the cross-matrix switch 7 is connected to a standard or subscriber telephone or wired distribution block 5. Typically, the type Bix and no. 66, although the configuration of distribution block 5 does not affect the operation of the invention. Distribution block 5 connects the output of the cross-matrix switch 7 with a pair (red / green) of the existing telephone system or PSTN. The distribution block 5 can also be used for wiring with Category 5 or 10-base-T cable.

Redistributor 8 may also include an HDTV processor 144 for processing HDTV signals received by an HDTV input 140 via an antenna, satellite dish or other suitable receiver 142. An HDTV processor 144 is connected directly to a server 6 that controls the selection

-9channels and routes an HDTV signal through a high-speed data router or node 150 that distributes HDTV signals from server 6 through a coaxial or category five or six (10-base-T) network within a multi-user area. PSTN wiring is also not capable of transmitting HDTV signals and thus requires a coaxial or category five or six cable to connect the HDTV output from server 6 directly to receiver 2. If a category five or six cables (typically having 4 pairs) are used, the HDTV signal requires only two pairs and two unused pairs can be connected to PSTN distribution block 5, as shown in Figure 1, to effectively combine telephone wiring (red (green and yellow / black) with unused pairs in category five or six cables.

Additionally, a database 146 for storing movies can be directly connected to a server 6 that controls the selection of films in response to user input commands that it provides based on the directory accessed through the movie sub-menu.

The signal audio / video output provided by redistributor 8 is transmitted to the communication units 100 in individual units via unused wires in the PSTN, which are typically black / yellow. The PSTN has no voltage or frequency limit and can transmit the entire audio / video signal band over a considerable distance with minimal signal loss.

The communication interface 100 shown in Figure 3 receives modified signal combinations from the redistributor 8. Here, they are separated into individual audio and video signals by separator 102. In preferred embodiments, the video signal has a range from DC to 4.5MHz for NTSC, PAL or SECAM and the audio sub-carrier frequency is in the range (but not limited to) from 4.6 to 5.0MHz, preferably 4.7MHz.

The output of separator 102 is connected to audio demodulators 104 and video demodulators 106. The video output from the separator has a preferred impedance of 75 to 100 ohms, depending on the network properties and settings of the video modulator in redistributor 8, which will compensate for the loss due to maladaptation and reflection. The video signal can be transformed to be attached to the H sync and color spikes using horizontal sync attenuation and an amplifier operated by redistributor 8 to regulate the sync level to receiver 2 so that unauthorized video recording is prevented (a typical television set is capable of synchronizing a video signal with as little as 15 sync units, while video recorders typically require 25 sync units, to synchronize effectively with the input signal).

-10Optionally, a signal-to-noise detector may be provided in communication interface 100, which signals to the redistributor 8 to increase the level of the audio / video output if the signal-to-noise ratio falls below a certain level. This would allow redistributor 8 to compensate for different lengths of telephone cable between distribution block 5 and communication interfaces 100 in different individual units (for example, an apartment at the top of a tower will have a smaller attenuation than a rooftop mounted redistributor 8 than a ground floor apartment located in the same multi-user location ). The system analyzer can also be connected directly to the RJ11 input in the communication interface 100 to test the various signals used by the system and can communicate directly with the server 6 to record the results of the system analysis.

The video demodulator 104 then converts the converted video signal to a standard composite video signal at 1Vpp for input to modulator 110. The demodulator 104 also filters reflection and other radio frequency and electromagnetic interference. Modulator 110 modulates a video signal to a selected channel, such as channel 3, using conventional NTSC, PAL, and SECAM modulation techniques. Modulator 110 is preferably a phase-locked loop with a saw filter and is frequency active within the 1GHz band. The communication interface 100 may be provided with a user-operated switch (not shown) to select channel 3 or 4, which is standard for home video receivers.

The output of modulator 110 is connected directly to the receiving device 2. In a preferred embodiment, the receiving device 2 is a television set, although it may also be a VCR, a stereo receiver or any device capable of receiving audio / video signals.

The sub-carrier frequency audio signal outputs the separator 102 and demodulates it (stereo or mono) audio demodulator 104 to a normal audio frequency range from about (but not limited to) 20Hz to 20kHz with an impedance that can vary from 75 to 600 ohms for input into modulator 110 and optionally directly into audio output. The demodulator 104 also filters radio frequency and electromagnetic interference.

Data modulator 120 sends feedback commands from the interfaces to the redistributor 8, which receives a variable data stream from one of a plurality of interfaces, preferably containing an optical interface, such as an infrared receiver 122 with a photodetector to receive a signal from a conventional manual IR remote control 123. to enter a numeric

-11information that controls the selection of input signals and the selection of channels where the input signal includes a plurality of channels (eg CATV television signal). The IR receiver 122 may be integrated into the communication interface 100, or connected to the conductor 100 with a communication interface 100 and mounted in a convenient location such as, for example, a television receiver 2. In a preferred embodiment, the remote control 123 controls the on, volume, and muting of the sound and picture / sound settings of the television 2 directly through the television IR reception system. All other choices are managed by the redistributor 8 based on command signals entered by the user into the infrared receiver 122 with the remote 123, from which they are forwarded to the redistributor via PSTN wiring (for ringing).

Communication interface 100 may also include data input 124 for connection to other types of input devices, such as, for example, a keyboard, mouse and / or control lever, a barcode and / or card reader, and any input device capable of entering alphanumeric information for interaction. Data input 124 is not limited by protocol, standards, speed, clock, or voltage.

Data modulator 120 is preferably also inductively coupled or directly capacitively coupled to the PSTN telephone jack as in 132. Conventional PSTNs reach the user directly without compromise, so that the telephone, facsimiles and the internet all function normally. The modulation scheme is selected according to the requirements of the data backflow. The FSK has been shown to work favorably. Frequency bandwidth is variable and frequency allocation is fast. Frequency in the 160 to 190kHz range has proven to be effective and does not interfere with telephone signals (typically in the 300Hz to 1.5kHz range). The data modulator 120 includes a high and low bandwidth filter and can operate at a data rate of 300 to 30,000 bps or otherwise, if necessary. The communication interface circuitry 100 may be programmed in ASIC or similar hardware.

The network card 132 can operate with any unused pair, whether it is included in the telephone wiring harness or it is a separate category five cable. The network card is not limited to the IEEE 10-basic-T standard, although this protocol is preferred. Network card 132 provides an optional interface for connecting a server user or computer to the system of the invention. Any computer 134 that is based on a microprocessor can be connected to a network card 132 and may have peripherals such as printers, scanners, modems, and the like. Network Card 132 can be advantageously used in newer multiuser areas where

-12 Existing telephone network provides at least three pairs (usually between 4 and 8) in a PSTN cable.

In a preferred embodiment, the information entered into the communication interface 100 using these feedback devices is forwarded to the redistributor 8 via a red / green pair in the telephone cable used in the telephony for ringing. These command signals are preferably emitted at a carrier frequency of about 150kHz. The content of the command signals is sparse enough to require a very small bandwidth and is preferably filtered so that it does not interfere with telephone services. The ring pair can be used to provide power to the communication interface 100 or, if the telephone operator does not provide sufficient power to power the communication interface 100, it can be powered directly from the transformer (not shown) in the redistributor 8, which outputs a direct signal together with video signal via yellow / black pair.

Using the 123 remote allows the user such services as shopping, banking, e-commerce, games and the like, which is currently accessible via the Internet. It would also be possible to transmit audio / video signals via the yellow / black PSTN pair without interfering with the video input signal. This would increase the level of interaction and allow for such complex data exchange features as video conferencing.

In a preferred embodiment, several carrier frequencies are introduced using a frequency division multiplexer or an orthogonal frequency division multiplexer as follows: DC up to 4.5MHz for video data signals; 4.55MHz for serial audio (BTSC stereo audio) signals; 8.5 to 12MHz for fast data signals; and 12 to 13MHz for audio data. Higher carrier frequencies have higher attenuation losses, electromagnetic and radio frequency interference, so in this embodiment the carrier carrier frequency for sound is preferably limited to a rather narrow band due to loss minimization. Other frequency bands may also be selected as to the suitability of the different modulation modes available. Broadcasting, which is common on AC power lines, can also be used to provide signals for additional audio and data lines, for input to a printer, for renting pay-for-use software and the like.

-13When installing the system according to the invention, redistributor 8 is installed on a multi-user site near the common distribution point for telephone wiring. This could be, for example, a main telephone panel in a commercial office building, apartment block or hospital, a local distribution box in the living area and the like. The output of the cross-matrix switch 7 is connected to a yellow / black pair in the PSTN or any other unused pair in the PSTN cable to transmit the selected input signal to the communication interface 100. The input of the cross-matrix switch 7 is connected to the red / green pair (or equivalent ringing conductor) ) in a PSTN cable to transmit command signals from communication interface 100 to redistributor 8.

One or more communication interfaces 100 are installed in individual units within the area. Each communication interface 100 has at least a remote command interface such as an optical interface 122 that is connected to the red / green PSTN. The output for connection to the receiving device 2, such as a conventional 75 ohm coaxial connector, is connected to the yellow / black PSTN pair. The network card 132 is optionally connected to another unused pair in the PSTN cable as an interface to a PC, microcomputer or computer network 134.

This system is operated by an operator who can pay different suppliers of input signals (where input signals are charged) and charge individual units a fee for using the system, or individual units pay bills directly to signal suppliers. Server 6 maintains a database through which it tracks and records all incoming signals and user channel selections at the multi-user site for billing. The operator may also use this information to produce viewership and other statistical and similar information. An operator may interrupt or replace the program in any output signal at any time, for example due to commercial notification, emergency messages, or the like, with the override signal located on server 6.

An operator may combine telephone services with other services, such as selling long-distance telephone services through designated inputs. A single-pair telephone cable is capable of transmitting multiple audio and data lines and can provide services to multiple lines and additional connectors in the unit. The divestiture scheme could include the length of use of the pay phone service and any other divestment scheme.

-14 In a preferred embodiment, the communication interface cover 100 is provided with a switch that is interrupted when the cover is removed, which immediately indicates tampering to prevent piracy of signaling services.

In use, the receiving device 2, preferably a conventional television set, is tuned to channel 3 or 4, which is optionally set by the user. When TV 2 lights up, the redistributor is placed on the main menu or on the last input signal selected by the specified user. An example of a main menu for a preferred embodiment is shown in Figure 3. Each menu option has a corresponding numeric selection parameter selected by the user with a 123 remote. The user selects his choice by entering the corresponding number in the remote 123. The optical interface 122 is numerically selected, and the corresponding command signal is transmitted to the redistributor 8 via the red / green PSTN and the server 6 via the cross-matrix switch 7.

The selected menu option can provide any number of sub-menu levels. For example, if the television option is selected by entering number 1, server 6 may switch to a submenu that offers 1-antenna, 2-CATV, 3-HDTV, and 4-DSS options. Using the same remote 123, the user selects the numeric values ​​corresponding to the desired selection, followed immediately by an instruction to enter the channel number. The main menu, submenus, and instructions are generated by the standard browsing software located on server 6. The selectable options can also be enabled in the void of the vertical interval of the video input signal, which is accessible by pressing a hot button on the remote 123, when information (such as a website URL) is displayed on the television 2.

Server 6 signals cross-matrix switch 7 via data bus A to connect the selected input signal to the output of matrix switch 90. The input signal is forwarded to the communication interface via a yellow / black pair (or other unused) PSTN. If the input signal contains multiple channels, for example in the case of television channels, server 6 controls the channel in the corresponding demodulator 14, 24 or 34 to transmit the selected channel. The input signal may be modulated to channel 3 or 4 and transmitted to an individual receiving unit on the user television receiver 2 via a conventional coaxial cable or another cable with two conductors. Alternatively, an input may be provided to directly connect the video and audio components to the television for viewing in video mode, which would eliminate the need for an output modulator 110 in the communication interface 100.

-15Server 6 capacity is selected based on the number of individual units in multiple user areas. Server 6 provides a separate cross-matrix switch 7 for each individual unit and can therefore independently transmit the input signal to each unit regardless of the input signals selected by other users. The choice of input signals is limited only by the capacity of the redistributor 8 to receive signals in any particular format. Where an individual unit has more than one television set 2 and has an additional pair of telephone wiring, the redistributor 8 may be provided with a separate cross-matrix switch 7 for each television set 2 within the unit. Thus, an eight-pair cable can supply up to four separate TVs 2 within the unit, each TV using one pair for audio / video input and output and another pair for transmitting command signals to the redistributor 8. This capacity can be further increased by assigning an identification number to each communication interface 100 within the unit and using a ringtone to transmit command signals to the redistributor 8 for all television sets 2 within the unit; redistributor 8 receives the identification number and directs the audio / video signal along the pair corresponding to the communication interface 100 that has been identified.

Since telephone wiring in an individual unit acts as a common distribution point for that particular unit, a reduced embodiment of the invention may be used to control the signals received by the television set 2 in the unit. For example, redistributor 8 may receive signals from an antenna, a closed system, and CATV signals transmitted to the unit via coaxial cable and 300 ohm wiring, and when connected to telephone wiring in the manner described above, television 8 may be remotely switched from a single signal input to another.

In a further embodiment of the invention, communication is carried out between the redistributor 8 and the receiver 2 via a single telephone pair. In this embodiment, the earthing conductor of the building is used as a total mass for redistribution and for command signal leads. In this embodiment, the redistributed signals are transmitted to the receiver via grounding and one conductor in the ring pair, and the command signals are transmitted to the redistributor 8 via grounding and the other conductor in the ring pair. The potential grounding difference can be compensated for by DC reconstruction using an operational amplifier to compensate for the 60Hz AC signal noise generated by the building's power lines. This embodiment is advantageously utilized in older buildings, where there is, for example, only one telephone pair, to avoid the installation of new wiring for the introduction of the system of the invention.

-16 The invention is thus described by way of examples of preferred embodiments and it will be readily apparent to those skilled in the art that certain modifications and adaptations can be made without departing from the scope of the invention as described in the following claims.