To access current communication services, for video, voice and/or data (VVD communication services), such as cable television and telephone services, it is often necessary to install separate wiring for each type of service. This wiring is in addition to the AC wiring used to distribute electrical power throughout a customer's premises. Conventional wiring used in buildings, such as residential homes, varies depending upon the application for which it is being used. Typically, cable television and video transmissions use coaxial cable wiring, telephones use bundled telephone wire and PBX telephone systems use twisted pair wiring. AC power is usually distributed over copper electrical wiring. Aluminum wiring has also been used for AC power. Computer networks typically use either, or both, coaxial cable or twisted pair wiring. Some homes use antenna wire (300 ohm) for receiving television/and or radio signals. Conventional wiring can also include any other type of wiring that is used for carrying electricity for either power or electrical signal communication.
Houses and buildings (customer premises), which were not originally wired with coaxial cable for video transmission and cable television, require the addition of coaxial cabling to every room where a television set is desired. In running new coaxial cable to each of these rooms, it is often necessary to drape the cable over the outside walls of the house and then drill holes into each room to run the cable into the room. Inside the room, the cable receptacle is often placed at the entry point into the room. This avoids the cost and effort involved in pulling cable through walls. If an outlet is located away form the entry point, the cable is run along the baseboard to a desired location for the receptacle or outlet. Cable run in this manner is often unsightly and can provide a hazard if it comes loose from the baseboard.
A similar problem exists with respect to telephones when extra telephone outlets or additional lines are desired at a customer premises. With the advent of facsimile machines and computer modems, it is not uncommon to have several telephone lines running into a building, even a home. Particularly in a home situation, the number of telephone lines may exceed the number of paired wire present in the standard bundled telephone wire run to each room. Although some home telephone wiring is bundled in three pair (six wires), allowing up to three separate lines, it is more common to use wiring bundles of 2 pair wire, allowing only two separate lines at the end of a given cable run (i.e., a room) . A separates lines for a telephone, a facsimile machine and a computer modem requires more than the number of possible lines allowed if a home is wired with two pair telephone line. Additional telephone lines may be necessary for use in a home office or business.
If a local area network (LAN) is desired, it is necessary to install either or both coaxial wiring and twisted pair wiring to connect the nodes of the network to the network server and/or each other node. Adding network wiring is oftentimes more expensive than adding cable television or telephone wiring. Network wiring must be installed carefully to ensure that there are no cuts or kinks in the wire which could impede data flow or integrity of the data being transmitted.
Although fiber optic cable could also be an option for VVD wiring, it is very expensive for inter home or building use. At the present time, fiber optic cabling is more commonly used in high volume VVD applications, rather than intra building applications.
In Applicant's co-pending applications, U.S. Ser. Nos. 07/822,326, filed Jan. 17, 1992 and 07/884,123, filed May 18, 1992, copies of which are attached hereto as Appendices A and B respectively and made a part hereof, there are described systems and methods for transmitting and receiving information over electrical power lines using a dielectric core coupler, such as an air-core coupler. Information signals are transmitted over the electrical power lines at the same time electricity for AC power is transmitted. The information and the electrical power are both accessible at the same time and at the same location at a customer's premises.
Systems other than those described in Applicant's copending applications use AC power lines for transmitting information signals. One of the limitations of these systems is that they do not allow high-speed data/signal communication. The approximate data flow limit of 19.2 Kbaud of line-carrier modems, for instance, would be wholly inadequate for the transmission speeds of up to 10 Mbaud, achieved by a LAN, such as an Ethernet system. The transmission of video signals typically requires transmission rates on the order of 6 megabits per second (Mbps). Therefore video transmission can not be achieved in systems which do not allow high speed data transmission, such as systems using line-carrier modems.
Existing technologies for VVD communication include:
Cable Network Systems which deliver services over separately owned cable installations to set top converters and/or cable ready television set; PA1 Asymmetrical Digital Subscriber Line (ADSL) technology which delivers full duplexing data, video and voice at 1.544-6 Mbps over twisted pair wire; PA1 Broadband integrated Services Digital Network (B ISDN) Synchronous Optical Network (SONET) and Asynchronous Transfer Mode (ATM) Access technologies which will initially deliver interactive video and data at a 6 Mbps data rate; and PA1 Direct Broadcast Satellite, which requires a satellite dish at each location and then distributes television channels from a tunable receiver over coaxial line to a TV set (one receiver per television set). This technology is not data or voice oriented.