EP0149253A2
Expired / Lapsed
EP
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Data collection apparatus of multi-drop connection type
Assignee: Hitachi Ltd
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Filing: 1984-12-28
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Granted: —
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Expires: 2004-12-28
Abstract
Abstract A master station (1) and a plurality of slave stations (2-1, 2-2,... 2-N) are connected in multi-drop connection. A carrier wave on an upstream transmission line (9) between the master station (1) and the slave stations (2-1, 2-2,... 2-N) is demodulated and remodulated in each slave station and always maintained to be on-state. Both the modulating and demodulating devices are MODEM following CCITT V.28, respectively. Each MODEM is connected to the respective slave station by a signal line following EIAR3 232C.
Inventors
- 👤 Takao 36-3-103 Nishinarusawacho-1-Chome Yanai
- 👤 Yoshiaki Takahashi
- 👤 Toshio Ozawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 11:38
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/40; H04L12/40006; H04L12/403
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
190 words
A data collection apparatus of multi-drop connection type including a master station (I) connected to a downstream transmission line (9) through modulating means (3) and a plurality of slave stations (2-1, 2-2 ... 2-N) connected to said downstream transmission line through respectice demodulating means (4-1A, 4-2A, ... 4-N), said master station being provided to call one of said slave stations through said downstream tansmission line, each slave station being connected to an upstream transmission line (10-1, 10-2, ... 10-N) through respective modulating means (3-1, 3-1, ... 3-N), said master station being connected to said upstream transmission line through demodulating means (4), and said called slave station returning a response signal through said upstream transmission line to said master station, said data correction apparatus comprising second demodulating means (4-lB, 4-2B, ...) provided in each slave station apart from said respective demodulating means connected to said downstream transmisison line, said upstream transmission line being connected in series through said modulating means and said second demodulating means, and a carrier wave on said upstream transmission line being demodulated in each slave station and then re-modulated thereby to always maintain said carrier wave on-state.
Claim 2
Dependent Claim
190 words
A data collection apparatus of multi-drop connection type including a master station (I) connected to a downstream transmission line (9) through modulating means (3) and a plurality of slave stations (2-1, 2-2 ... 2-N) connected to said downstream transmission line through respectice demodulating means (4-1A, 4-2A, ... 4-N), said master station being provided to call one of said slave stations through said downstream tansmission line, each slave station being connected to an upstream transmission line (10-1, 10-2, ... 10-N) through respective modulating means (3-1, 3-1, ... 3-N), said master station being connected to said upstream transmission line through demodulating means (4), and said called slave station returning a response signal through said upstream transmission line to said master station, said data correction apparatus comprising second demodulating means (4-lB, 4-2B, ...) provided in each slave station apart from said respective demodulating means connected to said downstream transmisison line, said upstream transmission line being connected in series through said modulating means and said second demodulating means, and a carrier wave on said upstream transmission line being demodulated in each slave station and then re-modulated thereby to always maintain said carrier wave on-state.
Claim 3
Dependent Claim
20 words
A data collection apparatus according to Claim 1, wherein said modulating means and said demodulating means are MODEM following CCITTV.28.
Claim 4
Dependent Claim
32 words
A data collection apparatus according to Claim 1, wherein said modulating means and said demodulating means are connected to said each slave station through a signal line (MODEM-1) following EIA R3 232C.
Claim 5
Dependent Claim
30 words
A data collection apparatus according to Claim 1, wherein said modulating means and said second demodulating means are connected with each other by a signal line (MODEM-2) following EIAR3 232C.
References Cited (Backward Citations)
No citation records indexed.
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