the Post Office
159Patents
0Active
159Granted
42Portfolio score
Filing activity: Nov 19, 1973 → Mar 24, 1999
Most-cited patents
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US4125768A | Apparatus for launching or detecting waves of selected modes in an optical dielectric waveguide | Physics | 208 | Expired |
| US4027331A | Digital television system | Electricity | 116 | Expired |
| US4509635A | Sorting system | Emerging Cross-Sectional Technologies | 82 | Expired |
| US4038489A | Cables | Physics | 80 | Expired |
| US4873662A | Information handling system and terminal apparatus therefor | Electricity | 69 | Expired |
| US4346601A | Testing glass fibres | Physics | 65 | Expired |
| US4237339A | Audio teleconferencing | Electricity | 62 | Expired |
| US4456331A | Improved communications cable with lines of weakness | Physics | 58 | Expired |
| US4309671A | Control apparatus | Electricity | 53 | Expired |
| US3970795A | Measurement of noise in a communication channel | Electricity | 46 | Expired |
| US4452506A | Coupling of dielectric optical waveguides | Emerging Cross-Sectional Technologies | 44 | Expired |
| US4500116A | Identification matter | Emerging Cross-Sectional Technologies | 41 | Expired |
| US6227378A | Sorting system for groups of items having recirculation | Emerging Cross-Sectional Technologies | 39 | Expired |
| US4278835A | Submarine communication cable including optical fibres within an electrically conductive tube | Physics | 37 | Expired |
| US4128140A | Apparatus for recycling engine lubricating oil | Mechanical Engineering; Lighting; Heating | 36 | Expired |
| US4125658A | Apparatus for use in drawing or marking graphic characters on a surface | Emerging Cross-Sectional Technologies | 35 | Expired |
| US3982075A | Synchronization system for time division multiple access relay communications system | Electricity | 31 | Expired |
| US4124825A | Signal level stabilizer | Electricity | 27 | Expired |
| USD259419S | Telephone instrument | General | 26 | Expired |
| US4168212A | Determining semiconductor characteristic | Electricity | 26 | Expired |
| US4456789A | Audio teleconferencing | Electricity | 26 | Expired |
| US4193121A | Information handling apparatus having multiple ports distributed around shifting register rings | Physics | 24 | Expired |
| US4262283A | System for transmitting alarm information over telephone lines | Physics | 24 | Expired |
| US4417387A | Gold metallization in semiconductor devices | Electricity | 23 | Expired |
| US4074228A | Error correction of digital signals | Electricity | 23 | Expired |
Source: USPTO / EPO open patent data. Counts and citation impact are objective bibliographic measures.