Extended range computer communications link
US5257390A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 26, 1991 |
| Grant date | Oct 26, 1993 |
| Priority date | — |
| Expiry date | Jul 26, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/0278
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
This invention is an extended range communications link having a first signal conditioning network located near and coupled to a computer. The network conditions keyboard clock, keyboard data, logic ground, mouse clock, mouse data, R, G, and B analog video signals, and multiplexes HS and VS sync signals. Conditioning of the video signals includes reducing their amplitude so the video signals do not significantly cause induced crosstalk in conductors adjacent to the video conductors. An extended range cable up to about 800 feet in length and having a plurality of conductors is coupled to a signal conditioning circuit and conveys the conditioned, above-named signals, in addition to power and logic ground potentials, to a second signal conditioning network. The network restores the analog video signals to their original levels by discrete video amplifiers having constant current characteristics that do not cause power fluctuations to occur in the power conductors of the cable, also reducing induced noise. Additionally, the signal conditioning network demultiplexes the sync signals and further conditions the mouse and keyboard signals and the power and ground potentials prior to inputt…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.