Dual speed full duplex data transmission
US4069392A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1976 |
| Grant date | Jan 17, 1978 |
| Priority date | — |
| Expiry date | Nov 1, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/50
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A dual-speed, dual format full-duplex two-wire voiceband data transmission system provides automatic speed selection at the answering terminal responsive to a handshaking sequence which is compatible with existing systems operating at telegraph speeds. Existing systems provide asynchronous full-duplex serial data transmission in the speed range of zero to 300 bits per second using frequency-shift keying of tones in split frequency bands dedicated to the respective transmisson directions. Alternative full-duplex serial data transmission at 1200 bits per second using phase-shift keying of carrier waves in these same split frequency bands can now be provided from a common line protocol.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.