Full duplex communication system for voice grade channels
US4355397A · kind A · utility
22Cited by
7References
35Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 15, 1980 |
| Grant date | Oct 19, 1982 |
| Priority date | — |
| Expiry date | Oct 15, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/3827
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A pair of full duplex modems (12, 14), each at one end of a two-wire voice grade telephone channel (16), simultaneously transmit synchronous data at high speeds in both directions. In each modem, the simultaneous transmission and reception are accomplished by frequency division. The high speed operation is obtained by odd/even bit stream division and full response binary to ternary level coding coupled with nine level quadrature amplitude modulation and correction framing techniques.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.