Method and apparatus for communicating digital signals over telephone lines
US4578538A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1984 |
| Grant date | Mar 25, 1986 |
| Priority date | — |
| Expiry date | May 16, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/00
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method for effecting the communication of digital signals over telephone lines includes the steps of generating a voltage at a first level for providing an inactive state signal directed to a plurality of slave transceiver units and generating a voltage at a second level for provding a first carrier detect signal directed to the slave units. A digitally encoded first data signal is then generated, has a peak amplitude at a third voltage level and is also directed to the slave units. In response to the first carrier detect and first data signals, a voltage will be generated at a fourth level for providing a second carrier detect signal directed to a master transceiver unit. Thereupon, a digitally encoded second data signal will be generated to have a peak amplitude at a fifth voltage level and is also directed to the master transceiver unit. An active bridge apparatus for effecting the communication of digital signals over telephone lines includes an isolated input circuit adapted to be coupled to a master transceiver unit by a single, twisted first pair telephone line. The unit includes a control section for transmitting an inactive state signal at a first voltage level to a plur…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.