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Multiple item radio frequency tag identification protocolMultiple item radio frequency tag identification protocol description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070176751, Multiple item radio frequency tag identification protocol. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present application is a division of application Ser. No. 10/979,866 filed Nov. 2, 2004, which is a continuation of application Ser. No. 09/179,481 filed Oct. 27, 1998, now U.S. Pat. No. 6,812,852 issued Nov. 2, 2004, which is a continuation of application Ser. No. 08/646,539 filed May 8, 1996, now U.S. Pat. No. 5,828,318 issued Oct. 27, 1998. Said application Ser. No. 09/179,481 is a continuation-in-part of application Ser. No. 08/694,606 filed Aug. 9, 1996, now U.S. Pat. No. 5,942,987 issued Aug. 24, 1999, which in turn is a continuation-in-part of application Ser. No. 08/303,965 filed Sep. 9, 1994, now U.S. Pat. No. 5,673,037 issued Sep. 30, 1997. Reference is also made to U.S. Pat. No. 5,550,547 which is commonly owned with the aforementioned applications. Said U.S. Pat. Nos. 5,550,547, 5,673,037 and 5,828,318 are hereby incorporated herein by reference in their entireties, including material incorporated in said U.S. Pat. Nos. 5,550,547, 5,673,037 and 5,828,318 by reference. Application Ser. No. 10/979,866 filed Nov. 2, 2004, is hereby incorporated herein by reference in its entirety including material incorporated in said application Ser. No. 10/979,866 by reference. GENERAL DISCUSSION OF THE DISCLOSURES INCORPORATED HEREIN BY REFERENCE [0002] Because the master often does not know ahead of time the number of slaves present and because that number may be very large and possibly unwieldy, it is advantageous for the master to be able to select a subset of the slaves with which to communicate further. Such a selection must of course be done by a conditional. Those slaves that meet the condition are thus considered selected, while those that do not meet the condition are considered not selected. The selection is performed by broadcasting to all slaves the condition that must be met. This is akin to asking those among a large crowd of people whose last name is Lowell to raise their hand. Each slave is defined as having at least the capability to listen to the master's broadcasts, to receive the broadcast condition and to self-test so as to determine whether it meets the condition. See U.S. patent application Ser. No. 08/303,965, to Cesar et al. filed on Sep. 9, 1994, now U.S. Pat. No. 5,673,037 issued Sep. 30, 1997, which is herein incorporated by reference in its entirety. U.S. Pat. No. 5,673,037 in turn incorporates U.S. Pat. No. 5,550,547 by reference in its entirety, and accordingly, U.S. Pat. No. 5,550,547 is hereby incorporated herein by reference in its entirety. U.S. Pat. No. 5,550,547 discloses a base station with a base memory (220, the second figure of Pat. No. 5,550,547) which stores a special command structure that is used to communicate with the RFID tags. In a preferred embodiment, the base memory includes a novel command structure for tag group selection also. U.S. Pat. No. 5,550,547 states that group select structures are described in the U.S. patent application Ser. No. 08/303,965 entitled "SYSTEM AND METHOD FOR RADIO FREQUENCY TAG GROUP SELECT" to C. Cesar et al. filed Sep. 9, 1994 (now U.S. Pat. No. 5,673,037), which is incorporated by reference in its entirety in U.S. Pat. No. 5,550,547. The fifth figure of the incorporated U.S. Pat. No. 5,550,547 shows an algorithm being executed by each of a plurality of RF tags which includes processing of an identification command which in a preferred embodiment is the group select command. FIELD [0003] This invention relates to the field of radio frequency (RF) tag identification. More specifically, the invention relates to the field of identifying and reading information from more than one RF that transmitting at simultaneously. BACKGROUND [0004] Radio Frequency Identification (RF ID) is just one of many identification technologies for identifying objects. The heart of the RF ID system lies in an information carrying tag. The tag functions in response to a coded RF signal received from a base station. Typically, the tag reflects the incident RF carrier back to the base station. Information is transferred as the reflected signal is modulated by the tag according to its programmed information protocol. [0005] The tag consists of a semiconductor chip having RF circuits, logic, and memory. The tag also has an antenna, often a collection of discrete components, capacitors and diodes, for example, a battery in the case of active tags, a substrate for mounting the components, interconnections between components, and a means of physical enclosure. One variety of tag, passive tags, has no battery. They derive their energy from the RF signal used to interrogate the tag. In general, RF ID tags are manufactured by mounting the individual elements to a circuit card. [0006] Basically, passive RF tags consist of two basic parts: [0007] a) An analog circuit which detects and decodes the RF signal and also provides power to the digital part of the Tag using RF field strength from the Base Station, and [0008] b) A digital circuit which implements the multiple items of the tag identification protocol. [0009] A radio frequency (RF) identification system also consists of an RF base station and a plurality of RF tags. [0010] In a typical configuration, the base station has a computer section which issues commands to an RF transmitter and receives commands from the RF receiver. The commands serve to identify tags present in the RF field of the base station. In some implementations, commands exist to gather information from the tags. In more advanced systems, commands exist which output information to the tags. This output information may be held temporarily on the tag, it may remain until over written, or it may remain permanently on the tag. [0011] The RF transmitter of the base station encodes the command from the computer section, modulates it from a base band to the radio frequency, amplifies it, and passes it to the RF antenna. The RF receiver gathers the return signal from the antenna, demodulates it from the RF frequency to the base band, decodes it, and passes it back to the computer section for processing. The base station antenna sends RF signals to and receives RF signals from one or more tags with in the RF signal range. [0012] While the application of RF ID technology is not as widespread as other ID technologies, bar code for example, RF ID is on its way to becoming a pervasive technology in some areas, notably vehicle identification. [0013] Multiple objects can be identified by checking each individually using bar code reader. However, this process consumes a lot of time. It is also error prone--the error rate made by either human beings or by the bar code reader is very high. [0014] This iterative process can be simplified and solved by introducing the RFID Tag technology. The RFID tag can be used to identify multiple objects in a very short time, on the order of a second. [0015] One way of implementing multiple RF tag identification is as follows: [0016] a. the tag powers up in the RF field, starts a clock, and seeds a random number generator. [0017] b. the tag sends out a 64-bit ID (at internal clock frequency) at intervals determined by the random number generator [0018] c. the base station synchronizes to the tag transmission from a transmitting tag in the field. If there is a successful reception (no errors), the station uses a power interruption to transmit a simple shutdown code to the tag. This approach works because the station is synchronized so that tag and times its shutdown code using that tag frequency. The tag uses the gap detection circuitry to identify power interruptions. [0019] d. Two shutdown modes are available: i) the tag is prevented from talking as long as it remains in the field; and ii) the tag is prevented from talking even after departing field (for approximately 10 minutes or more.) The shutdown mode (ii) is accessible only after shutdown mode (i) has been entered. [0020] e. In this application, multiple items are identified by shutting down each tag immediately after a successful read. Other tags in the field, ideally, will not be synched to the internal frequency of the tag which has just been read, nor, ideally, will they have just finished transmitting their id when the base stations sends the shutdown signal to the tag which has just been identified. Continue reading about Multiple item radio frequency tag identification protocol... Full patent description for Multiple item radio frequency tag identification protocol Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Multiple item radio frequency tag identification protocol patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Multiple item radio frequency tag identification protocol or other areas of interest. ### Previous Patent Application: Telecom equipment with rfids Next Patent Application: Methods and apparatus for reducing power consumption of an active transponder Industry Class: Communications: electrical ### FreshPatents.com Support Thank you for viewing the Multiple item radio frequency tag identification protocol patent info. 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