Method and apparatus for bi-directional communication via existing CATV system
US3943447A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 8, 1974 |
| Grant date | Mar 9, 1976 |
| Priority date | — |
| Expiry date | Oct 8, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2203/5491
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Existing CATV coaxial cable systems are found to present a transparent window, in both the upstream and downstream directions, to communications signals over a frequency band from 10-300KHz, whereby such signals follow the path of the 60Hz power signal throughout the system. Signals in this band do not interfere with the high frequency TV signals being transmitted, and are not subject to interference by such TV signals. This discovery is thus utilized to implement bi-directional communications between any two or more points linked by such a CATV system without requiring any substantial modifications or additions to the existing system components. A specific application utilizes such a communications link to remotely control non-duplication switching in the head or antenna end of a CATV system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.