Data transfer method for a scanning identification system

• US 6,426,692 B1
• Filed: 06/14/1999
• Issued: 07/30/2002
• Est. Priority Date: 09/13/1996
• Status: Expired due to Term

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Inventors: Friedrich, Ulrich, Blatz, Werner, Grosskinsky, Ulrich, Bruhnke, Michael
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): BANGACHON, WILLIAM L
• Application Number:
  US09/254,867
• Time in Patent Office: 1,142 Days
• Field of Search: 340/10.1, 340/10.3, 340/10.4, 340/10.5, 340/10.32, 340/10.34, 340/10.51, 340/10.41, 340/3.2, 340/3.41, 340/3.61, 340/10.2, 342/42, 235/380, 327/525
• US Class Current: 340/10.4
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/40975 using encryption therefor
• CPC Class Codes: G07F 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: G11C 11/419 Read-write [R-W] circuits
• CPC Class Codes: G11C 7/1048 Data bus control circuits, e.g. precharging, presetting, equalising
• CPC Class Codes: G11C 7/1051 Data output circuits, e.g. read-out amplifiers, data output buffers, data output registers, data output level conversion circuits

Abstract

In a method of transferring data from a transponder to a reading device in a scanning identification system through load-modulation of an inquiry signal emitted by the reading device, with the transponder being initialized at the beginning of the reception of the inquiry signal and responding with the emission of the response signal, first a predetermined number of data bits that are not part of the response signal are transmitted, and a terminator sequence followed by the response signal are repeatedly transmitted, until the inquiry signal is interrupted. The time required by the reading device for building up the inquiry field is bridged by the predetermined number of data bits and, at the same time, the reading device is synchronized to the clock of the response signal. Through the terminator sequence, which indicates the beginning of a valid response signal, the response signal is already recognized correctly by the reading device during the first transfer.

Claims

1. A method of transferring data from a transponder to a reading device in a scanning identification system through load modulation of an inquiry signal emitted by the reading device, with the transponder being initialized at the beginning of the reception of the inquiry signal and responding with the transmission of a response signal, and wherein first a predetermined number of data bits that are not part of the response signal are transmitted, and then a terminator sequence followed by the response signal are repeatedly transmitted until the inquiry signal is interrupted.

2. The method of transferring data according to claim 1, wherein the terminator sequence comprises a bit sequence that cannot occur in the actual response signal.

3. The method of transferring data according to claim 1, wherein the inquiry signal is not modulated for 1.5 bit periods during the transmission of the terminator sequence.

4. The method of transferring data according to claim 1, wherein the inquiry signal is load-modulated for 1.5 bit periods during the transmission of the terminator sequence.

5. The method of transferring data according to claim 1, wherein a sequence of three to ten logical ones is transmitted as the predetermined number of data bits that are not part of the response signal.

6. The method of transferring data according to claim 1, wherein a sequence of three to ten logical zeroes is transmitted as the predetermined number of data bits that are not part of the response signal.