Communications: electrical – Selective – Interrogation response
Reexamination Certificate
2001-08-31
2004-12-07
Zimmerman, Brian (Department: 2635)
Communications: electrical
Selective
Interrogation response
C340S010410, C340S928000, C340S870030, C342S042000, C341S032000
Reexamination Certificate
active
06828902
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally of the field of radio frequency identification (RFID) systems and devices intended to sense the presence of a transponder tag within a sensing field of a reader unit and to read an identification code unique to each such tag thereby to identify a person or object associated with the tag. More particularly this invention is directed to a passive remote programmer for reprogramming microprocessor controlled induction type RFID readers, and more generally, to wireless data input to RFID readers or devices associated with RFID readers.
2. State of the Prior Art
Radio frequency identification systems have come into widespread usage in a wide range of applications. One such application is controlling access to restricted areas of buildings or plant facilities by authorized personnel while excluding those lacking the necessary authorization. Most such proximity systems consist of a transponder, a reader and a host computer. The reader generates a radio frequency (usually in the 125 kHz or 13.5 MHz range). The transponder usually consists of an antenna circuit (tuned to the same frequency as the output of the reader) and an integrated circuit (IC). Sufficient energy to activate the PC is obtained via induction when the transponder is placed within the field of the reader. The frequency of the reader is also used as a clock for the IC. When energized, the transponder IC loads the antenna circuit of the transponder in a pattern determined by the design and programming of the IC. The loading of the transponder antenna is detected as a pattern of voltage changes on the reader's antenna circuit. The changes are converted into logical data bits using standard decoding methods and the data is then interpreted by the host and appropriate action (such as opening the door) is taken.
The topology of the various systems can range from a stand alone single door unit that contains the reader and the host in one small box mounted adjacent to a passageway to a complex system consisting of thousands of readers and other input/output devices connected to a communications network controlled by hundreds of host computers (running specialize software) that control access, personnel and property movement, lighting, HVAC, fuel dispensing and other functions. In stand alone, single door, products and in some systems with distributed intelligence, the reader and host are often combined into a single entity.
SecuraKey, a division of Soundcraft, Inc., the assignee of this invention sells a reader under the name Radio Key® 600 or RK600, described in their commercial literature as a “stand alone proximity/keypad access control system” which has a built-in programmer. This reader is of the inductive type and is intended to function in conjunction with key tags, also sold by the same assignee, which are passive bi-directional transponders in that power for the key tag is derived from the electromagnetic field generated by the reader. Each transponder consists of an integrated circuit and an antenna coil, both embedded in a small plastic token or tag. The integrated circuit of the transponder tag is a TEMIC e5550 contactless R/W-Identification IC (IDIC®) device sold by the semiconductor division of TEMIC TELEFUNKEN microelectronic GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany.
There is a need for periodically reprogramming such proximity systems as authorized personnel and access control requirements change. For example, as newly authorized individuals are issued transponder tags, the new tags must be entered into the reader's programmed data base in order to be recognized when presented to the reader. Likewise, tags need to be removed from the data base as personnel leaves or is reassigned. In large RFID systems such reprogramming is typically done through the host computer linked to multiple readers. In smaller systems or those lacking centralized control, reprogramming may need to be done at each reader. Conventionally, this may be achieved through a keyboard provided on the reader unit itself, as in the aforementioned RK600 reader. It is often desirable to provide means for remotely programming the reader for convenience or security reasons. Radio frequency linked hand held remote programmers are available for this purpose. Such units typically include a keyboard connected to a microprocessor which delivers programming data transmitted via a low power radio frequency carrier generated by the programmer unit. Also available are passive programmers which draw their operating power from the electromagnetic field emitted by the reader. Existing passive programmers, however, are microprocessor based and of considerable complexity. Also, the power requirements of these existing units is relatively large which results in a rather short operating range because the programmer must be brought sufficiently close to the reader where the field strength is adequate for powering the programmer. A continuing need exists for simpler, lower cost passive programmers, particularly for use with small or stand alone RFID installations.
More recently, RFID transponder tags have become available which are individually addressable by the RFID reader. That is, the tag does not automatically respond with its tag code when in the induction field of the RFID reader until it is specifically addressed or interrogated by the reader with that tag's unique tag identification code. This allows reading of multiple tags simultaneously present in the reader's radio frequency induction field. Exemplary of such tags are the I_CODE series of RFID tags sold by Philips Electronics, and the M35101 Contacless Memory Chip sodl by ST. Suitable RFID readers capable of reading multiple transponders simultaneously present in its induction field include theET-WS and ET-RS high frequency proximity readers sold by Secura Key, a Division of Soundcraft Inc. The RFID reader is preprogrammed with the unique identification code of each tag in the tag group or population to be read, and the reader executes a read scan or sequence during which it sequentially transmits, by modulating its induction field, the preprogrammed unique tag identification codes. The reader cycles through this read scan or sequence at a relatively high repetition rate sufficient to reasonable ensure that the presence of any one of the tags in the reader's sensing field does not go undetected.
SUMMARY OF THE INVENTION
This invention addresses the aforementioned need by providing a simpler passive remote programmer for induction type RFID readers. The novel remote programmer is of economical design, requiring only three main components: a keypad, an antenna and a number of commercially available, low cost transponder tags. Each of the transponder tags, when connected to the antenna by actuation of a key on the keypad, communicates with the RFID reader by loading down the magnetic field in the vicinity of the transmitter antenna of the reader in a pattern which the reader interprets and decodes as digital data.
More specifically, the passive remote programmer system of this invention is intended for use with an induction type RFID reader having radio frequency (RF) sensing means operatively connected to a digital processor, such as a microprocessor, for reading tag identification data of RFID transponder tags powered by a sensing field of the reader and for verifying the identification data against stored identification data thereby to recognize the presence of authorized tags.
The programmer which may be a hand held unit houses an antenna, such as a loop antenna, a number of dedicated RFID transponder tags each having a unique tag code, and a keyboard having a plurality of keys each selectively operable for connecting a corresponding one of the dedicated RFID transponder tags to the antenna thereby to inductively power the selected tag in the reader's sensing field and enable the unique tag code of the selected tag to be read by the said RFID reader. The remote programmer operates i
Law Offices of Natan Epstein
Soundcraft, Inc.
Zimmerman Brian
LandOfFree
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