Private automatic branch exchange system and apparatus
US4028498A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 7, 1974 |
| Grant date | Jun 7, 1977 |
| Priority date | — |
| Expiry date | Oct 7, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S379/914
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A private automatic branch telephone exchange system which includes an integral system for maintaining and updating selected data information. Interconnections between subscriber lines and trunk lines are accomplished with a unique non-blocking switching matrix which allows switching interconnections to be independently made and terminated without blocking subsequent interconnections on the same circuits. Various information signal functions, such as dial tone and ring-back, are selected by multiplex circuitry which is external of the switching matrix, so that all switching matrix trunks are available for voice and ring signal connections. The switching matrix is operated by a circuitry including a programmed digital computer, and provides substantial flexibility of control and service functions. Subscriber line status is monitored at all times, so that available special services can be accomplished by a subscriber in response to dialing selected digits. A novel coupler circuit is disclosed for interconnecting the present or another branch exchange system to central office lines. Subscriber dialing of a predetermined non-interconnect code allows a subscriber to dial updating input …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.