CATV telephony system using subsplit band for both directions of transmission
US5488413A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 14, 1994 |
| Grant date | Jan 30, 1996 |
| Priority date | — |
| Expiry date | Jun 14, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/10
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A cable television (CATV) system is modified to provide two-way telephone communications in a subsplit band below the video signal, preferrably in the range of approximately 5-40 MHz. Each line amplifier in the coaxial cable network is equipped with a bypass strap or bypass circuitry to maintain a signal path through the line amplifier for the telephone signal in the event of failure of the line amplifier. Due to the decreased attentuation resulting from its lower frequency, the telephone signal can typically travel the distance of three or four line amplifier spacings without amplification. Line amplifier failure is a common occurrence in CATV networks. Therefore, the present invention greatly increases the reliability of telephone communications over CATV networks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.