Patent EP0087252A2 successfully refreshed from Google Patents.
EP0087252A2
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EP
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Data transmission system
Assignee: Fujitsu Services Ltd
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Filing: 1983-02-14
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Granted: —
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Expires: 2003-02-14
Abstract
Abstract data transmission system is formed from a series of data transmission loops (2). Each loop includes an interface unit (3) for an attached device and is connected at either end to a synchronising and switching module (5) in a central unit. The loops (2) are connected by the modules (5) into a continuous data-transmission path connecting the interface units in sequence. The interface units (3) each act as a synchronous repeater and/or a source of fresh data. To prevent the accumulation of jitter in the clock signals derived in the interface units each module (5) contains a first-in first-out buffer (25) in which the data is resynchronised to a common clock source (7) used by all the modules. The modules (5) also bypass over a link (35) any loop which contains an inoperable unit.
Inventors
- 👤 Reginald Walter Stevens
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 20:41
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/42; H04L12/422
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
146 words
A data transmission system comprising a continuous path for the transmission of data in which path are interposed a plurality of interface means (3) each for transferring data from the path to an associated device (4) and/or from an associated device to the path, each interface means having means for deriving a clock signal from data received from the path and means responsive to that clock signal and capable of outputting onto the path data received from it, characterised in that there is provided a source of a clock signal and means (25) at a plurality of points on the path for resynchronising the data being transmitted on the path at each of those points to a clock signal from the said source (7), consecutive pairs of such points being separated from one another along the path by at least one of the said interface means.
Claim 2
Dependent Claim
146 words
A data transmission system comprising a continuous path for the transmission of data in which path are interposed a plurality of interface means (3) each for transferring data from the path to an associated device (4) and/or from an associated device to the path, each interface means having means for deriving a clock signal from data received from the path and means responsive to that clock signal and capable of outputting onto the path data received from it, characterised in that there is provided a source of a clock signal and means (25) at a plurality of points on the path for resynchronising the data being transmitted on the path at each of those points to a clock signal from the said source (7), consecutive pairs of such points being separated from one another along the path by at least one of the said interface means.
Claim 3
Dependent Claim
95 words
A system as claimed in claim 1 characterised in that the means for resynchronising the data on the said path comprises a plurality of first-in first-out buffer means (25) each interposed in the path at one of the said points and capable of storing a data bit for more than one bit period, data in operation being entered into each such buffer means in response to a clock signal (Rx) derived from the data received from the said path and being output from it in response to a clock signal from the said source (7).
Claim 4
Dependent Claim
128 words
A data transmission system as claimed in claim 1, characteristed in that the system comprises a plurality of data transmission loops (2) each including one of the said interface means (3), and coupling means (1) to which each of the said loops (2) is connected at either end, the coupling means (1) including the said source (7) for a clock signal and a plurality of data-transfer connections (19,20,25,26,6,10', 14') connecting the said loops (2) in sequence to form the said path, and the means for resynchronising the data on the said path comprising a plurality of means (25), one in each of at least some of the said data-transfer connections, for resynchronising the data being transmitted on that data-transfer connection to a clock signal from the said source.
Claim 5
Dependent Claim
40 words
A system as claimed in claim 3, characterised in that the coupling means (1) includes means (20,26,35) responsive to the absence of data being received from any of at least some of the said loops (2) to by-pass that loop.
Claim 6
Dependent Claim
25 words
A system as claimed in claim 4, characterised in that each of the loops (2) capable of being by-passed includes an optic-fibre data transmission medium.
Claim 7
Dependent Claim
41 words
A system as claimed in any one of claims 3 to 5 characterised in that each of the said means (25) for resynchronising data being transmitted on a data-transfer connection comprises a first-in first-out buffer means as specified in claim 2.
Claim 8
Dependent Claim
81 words
A coupling element suitable for use as the coupling means (1) in any one of claims 3 to 6, the said coupling element having a plurality of pairs of terminals (15,18) each pair being for connection to the two ends of one of the said loops (2), the said data-transfer connections each running from one terminal (18) of one of the said pairs to one terminal (15') of another of the said pairs and the said pairs being thereby'connected in sequence.
Claim 9
Dependent Claim
28 words
A data transfer system as claimed in any one of claims 1 to 6 characterised in that it includes the devices (4) associated with the several interface means.
Claim 10
Dependent Claim
18 words
A data transfer system substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
Claim 11
Dependent Claim
18 words
A data transfer system substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
Claim 12
Dependent Claim
17 words
A central unit substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
Claim 13
Dependent Claim
17 words
A central unit substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
References Cited (Backward Citations)
No citation records indexed.
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