发明名称 |
Dual speed full duplex data transmission |
摘要 |
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.
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申请公布号 |
US4069392(A) |
申请公布日期 |
1978.01.17 |
申请号 |
US19760737789 |
申请日期 |
1976.11.01 |
申请人 |
BELL TELEPHONE LABORATORIES, INCORPORATED |
发明人 |
GOLDENBERG, HENRY ROBERT;PECK, RICHARD JOHN;TONG, SHIH YUNG;WEBB, DAVID ALLEN |
分类号 |
H04B1/40;H04L5/14;(IPC1-7):H04Q5/00;H04M11/06 |
主分类号 |
H04B1/40 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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