American Telephone and Telegraph, Co.
400Patents
8Active
400Granted
44Portfolio score
Filing activity: Mar 27, 1975 → Sep 11, 1997
Most-cited patents
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US4837798A | Communication system having unified messaging | Electricity | 990 | Expired |
| US4953159A | Audiographics conferencing arrangement | Emerging Cross-Sectional Technologies | 631 | Expired |
| US4850007A | Telephone toll service with advertising | Electricity | 381 | Expired |
| US4922486A | User to network interface protocol for packet communications networks | Electricity | 356 | Expired |
| US4922522A | Telecommunications access to lottery systems | Emerging Cross-Sectional Technologies | 317 | Expired |
| US4937653A | Semiconductor integrated circuit chip-to-chip interconnection scheme | Electricity | 258 | Expired |
| US4897798A | Adaptive environment control system | Mechanical Engineering; Lighting; Heating | 236 | Expired |
| US4763353A | Terminal based adjunct call manager for a communication system | Electricity | 209 | Expired |
| US4679189A | Alternate routing arrangement | Electricity | 206 | Expired |
| US5164983A | Telemarketing complex performance management system | Electricity | 198 | Expired |
| US4924492A | Method and apparatus for wideband transmission of digital signals between, for example, a telephone central office and customer premises | Electricity | 193 | Expired |
| US5361259A | Wide area network (WAN)-arrangement | Electricity | 186 | Expired |
| US4653090A | Graphics based call management | Electricity | 178 | Expired |
| US4914650A | Bandwidth allocation and congestion control scheme for an integrated voice and data network | Electricity | 169 | Expired |
| US4816653A | Security file system for a portable data carrier | Emerging Cross-Sectional Technologies | 168 | Expired |
| US4897711A | Subassembly for optoelectronic devices | Physics | 160 | Expired |
| US4882474A | Security file system and method for securing data in a portable data carrier | Emerging Cross-Sectional Technologies | 159 | Expired |
| US4823338A | Virtual local area network | Emerging Cross-Sectional Technologies | 153 | Expired |
| US4670770A | Integrated circuit chip-and-substrate assembly | Electricity | 152 | Expired |
| US4748656A | Personal computer--as an interface between a telephone station set and a business communication system | Electricity | 146 | Expired |
| US4754479A | Station number portability | Electricity | 138 | Expired |
| US4769833A | Wideband switching system | Electricity | 136 | Expired |
| US4533795A | Integrated electroacoustic transducer | Emerging Cross-Sectional Technologies | 131 | Expired |
| US4900126A | Bonded array of transmission media | Physics | 131 | Expired |
| US4850036A | Radio communication system using synchronous frequency hopping transmissions | Electricity | 127 | Expired |
Source: USPTO / EPO open patent data. Counts and citation impact are objective bibliographic measures.