Keith Lynn Vertrees

US Patent:

58567887, Jan 5, 1999

Filed:

Mar 12, 1996

Appl. No.:

8/628872

Inventors:

Ronald Walter - Anaheim CA
Keith Vertrees - San Diego CA

Assignee:

Single Chips Systems Corp. - San Diego CA

International Classification:

G06F 300
G06F 700

US Classification:

34082554

Abstract:

A method and apparatus for determining the identification number or any other information within a plurality of radiofrequency identification tags within a common field of interrogation utilizes a combination of an isolation state into which the tags may be placed together with bitwise interrogation of the identification number or information followed by selective deactivation. A first bit in the identification number or information is interrogated of all the tags in the field. If any tag responds that the bit is a 1, a 1 is entered into an ID register in a reader and all tags in which a 0 exists in that bit position are deactivated. The process continues until only one tag remains activated. The last activated tag at this point has been completely read and is then placed in an isolated state. The process is begun anew with the remaining nonisolated tags until all tags have been read.