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EP0400764A2
Expired / Lapsed
EP
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Transaction system
Assignee: Marconi Communications Ltd
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Filing: 1986-04-07
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Granted: —
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Expires: 2006-04-07
Abstract
Abstract A transaction system enables a portable token to cooperate with a fixed terminal by being inductively coupled to the terminal. The terminal comprises means (6, 12) for transmitting a carrier signal and detecting a variation in the power demand thereof which is indicative of the presence of an inductively coupled token.
Inventors
- 👤 John Alexander Mccrindle
- 👤 Antony Francis Steiner
- 👤 Andrew Martin Jackson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:40
CPC Classifications
G; G07; G07B; G07B15/00; G07B15/06; G07B15/063; G06; G06K; G06K19/00; G06K19/06; G06K19/067; G06K19/07; G06K19/0723; G06K7/00; G06K7/0008; G06K7/10; G06K7/10009; G06K7/10118; G06K7/10128; G07C; G07C9/00; G07C9/20; G07C9/28
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
66 words
A transaction system including a terminal; a token having an on-board data processing capability; means (7, 32) for inductively coupling the token with the terminal to permit data communication therebetween and characterised by means (6, 11) associated with the terminal for transmitting a carrier signal and for detecting a variation in the power demand thereof which is indicative of the presence of an inductively coupled token.
Claim 2
Dependent Claim
66 words
A transaction system including a terminal; a token having an on-board data processing capability; means (7, 32) for inductively coupling the token with the terminal to permit data communication therebetween and characterised by means (6, 11) associated with the terminal for transmitting a carrier signal and for detecting a variation in the power demand thereof which is indicative of the presence of an inductively coupled token.
Claim 3
Dependent Claim
40 words
A system as claimed in claim 1 and wherein means (6) are provided for transmitting the carrier signal at a relatively low stand-by level which is raised to a higher operating level when a token inductively couples with the terminal.
Claim 4
Independent Claim
63 words
A system as claimed in claims 1 or 2 and wherein the token includes voltage detection means (39, 40) operative to initiate operation of the on-board processing capability when the detected voltage rises above a threshold level, and means (42-49) operative to shut down, in an orderly manner, operation of the on-board processing capability when the detected voltage falls below a threshold level.
Claim 5
Dependent Claim
37 words
A system as claimed in claim 3 and wherein the voltage detection means is operative to monitor the voltage induced in an inductive coil mounted on the token and which is operative to receive said carrier signals.
Claim 6
Independent Claim
30 words
A system as claimed in any preceding claim and wherein reception of data from the token is inhibited at the terminal whilst the terminal is transmitting data to the token.
Claim 7
Independent Claim
42 words
A system as claimed in any of the preceding claims and wherein the terminal is provided with an inductive loop (9) having a plurality of turns which is of larger area than a cooperating inductive loop (30, 31) mounted on the token.
Claim 8
Dependent Claim
28 words
A system as claimed in claim 6 and wherein the token is in the form of a plastics card having the inductive loop positioned around an edge thereof.
Claim 9
Independent Claim
59 words
A system as claimed in any of the preceding claims, and wherein an inductive loop which is carried by the token is tuned to the mean frequency of said carrier signal, and means (38) are provided for modifying the impedance of the loop in accordance with the data which is to be transmitted from the token to the terminal.
Claim 10
Dependent Claim
50 words
A system, as claimed in claim 8 and wherein the loop is switchably tuned between two predetermined frequency characteristics which represent the two binary states of data transmitted from the token to the terminal, the voltage level developed at said loop being substantially the same for the two frequency characteristics.
Claim 11
Dependent Claim
30 words
A system as claimed in claim 9 and wherein the loop is switchably tuned by switchably altering the reactance of a tuned circuit of which the loop forms a part.
Claim 12
Independent Claim
57 words
A system as claimed in any of claims 7 to 10 and wherein the inductive loop (9) at the terminal forms part of a tuned circuit (7) which is tuned to a resonant frequency which lies between two frequencies which represent different binary data states of the frequency modulation with which data is transmitted to the token.
Claim 13
Dependent Claim
26 words
A system as claimed in claim 11 and wherein the signal level developed across the tuned circuit is substantially the same for the said two frequencies.
Claim 14
Independent Claim
34 words
A system as claimed in any of the preceding claims, and wherein the carrier signal which is received by the token is used as its source of power to energise its on-board processing capability.
References Cited (Backward Citations)
EP0198642A2
Cited
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