Data transmission system between telephone subscriber location and telephone exchange location during idle telephone condition
US4059727A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 3, 1977 |
| Grant date | Nov 22, 1977 |
| Priority date | — |
| Expiry date | Jan 3, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/002
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An electrical data transmission system employs a telephone line to transmit data from a subscriber data equipment to a telephone exchange data equipment when the telephone line is idle. A first idle line sensing means is associated with the subscriber equipment and is operable to connect the line to the subscriber equipment when the line is idle and to disconnect the line from the subscriber equipment when the line is busy. A second idle line sensing means is associated with the exchange data equipment and is operable to connect the line to the exchange equipment when the line is idle and to disconnect the line from the exchange equipment when the line is busy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.