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`SELECTIVELY RETRIEVING MESSAGES
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`RELATED APPLICATIONS
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`Reference is made to co-pending patent applications filed on September 19,
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`1997, entitled "Paging Transceivers and Methods for Selectively Erasing
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`Information," "Pager Transceivers and Methods for Performing Action on
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`Information at Desired Times," and "Methods and Systems for Selectively
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`Paging," each filed by Richard 1. Helferich.
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`FIELD OF THE INvENTION
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`The present invention relates generally to paging transceivers and methods
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`for selectively acting on messages and, more particularly, to paging transceivers
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`and methods for selectively retrieving messages.
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`BACKGROUND OF THE INVENTION
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`In general, a paging receiver can be classified into one of four categories:
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`an alert or tone only paging receiver, a numeric paging receiving, an alphanumeric
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`paging receiver, or a voice paging receiver. One common characteristic of all of
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`these paging receivers is that they monitor the air waves and notify the user when
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`their particular address has been detected. For the alert or tone only paging
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`receiver, the paging receiver would generate a tone or beep when its address is
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`detected. The other paging receivers, upon detecting their address, would
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`additionally store a message associated with the address signal and display or play
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`it to the user. The message for a numeric paging receiver would be a set of
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`numbers, typically the calling person's telephone number, and the message for an
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`alphanumeric paging receiver would be a set of numbers and/or letters. The user
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`of an alphanumeric paging receiver could therefore receive a message in the form
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`of a telephone number with some descriptive text. For the voice paging receiver,
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`the message that is stored is a voice message that the user can later play to hear the
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`message.
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`A paging receiver is typically a rather small electronic device and,
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`accordingly, has a limited amount of memory for storing messages that have been
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`received from a base station in a paging system. Because of the relatively small
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`size of the memory, the paging receiver can store only a limited number of
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`messages. A user can delete messages from memory but will oftentimes desire to
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`save a message, such as temporarily until the user makes a note of the message or
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`until he or she is able to respond to the page. The messages that are saved in
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`memory, however, reduce the space in memory that is available to receive new
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`messages. This demand on space in memory is increasing as the size of the
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`messages continue to grow and as users receive a greater number of messages.
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`Although more memory can be added to accommodate more messages, the added
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`cost and space needed for extra memory runs counter to the desires to keep the
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`paging receiver small and inexpensive. A need therefore exists for a paging
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`receiver which can display messages while efficiently using memory.
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`In addition to the demand on paging receiver memory, paging systems will
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`be challenged as greater numbers of pages are being transmitted and as the size of
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`the transmitted messages increases. Initially, when paging systems were only
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`concerned with transmitting address signals of the paging receivers, the size of
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`each transmission by the paging systems was relatively small. Paging receivers
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`and paging systems, however, have undergone tremendous advances with paging
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`systems now transmitting messages which can be hundreds of kilobytes or greater
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`in size in addition to the address signals. Additionally, many paging receivers are
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`actually paging transceivers which transmit acknowledgment signals back through
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`the paging system. The capacity of the paging systems are therefore being
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`challenged not only by messages of increasing sizes but also by reply signals
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`transmitted from the paging transceivers to the paging system. The future of
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`paging systems is therefore tied to the ability of the paging systems to control the
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`number and size of the data transmissions and to provide additional features
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`without sacrificing the quality of service to the user.
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`As discussed above, many paging transceivers are able to issue a reply or
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`acknowledgment back to the base station in response to a received message. If the
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`base station does not receive this reply or acknowledgment, then the base station
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`assumes that the message has not been received and will repeatedly transmit the
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`message until the reply or acknowledgment is received. Due to the high power
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`levels at which the base station transmits its paging signals, the signals are usually
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`easily received by all paging transceivers located within the coverage area of the
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`base station antenna. The paging transceivers, on the other hand, must operate at
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`lower power levels and often cannot transmit signals at sufficiently high levels to
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`reach the base station. For example, when a paging transceiver is located in a
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`basement of a building, in a subway, or in an airplane, the paging transceiver may
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`be unable to issue a reply that can reach the base station. As a result, the base
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`station may continue to transmit a page to a paging transceiver and the paging
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`transceiver will continue to receive the message but the base station cannot detect
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`the reply being issued by the paging transceiver. This unnecessary transmission of
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`duplicate messages and the ineffectual reply signals transmitted by the paging
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`transceivers consume valuable resources of the paging system and of the paging
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`transcei ver.
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`For safety reasons, a user may at times have to turn off his or her paging
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`transceiver. For instance, when the user is on an airplane, the transmissions from
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`the paging transceiver can interfere with the instrumentation or communication
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`within the cockpit of the plane. The paging transceiver therefore should not be
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`operating within the plane or around other electronic equipment that are sensitive
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`to interference from the signals transmitted by the paging transceiver. As another
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`example, if the user is in an environment that contains electronic detonators for
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`explosive materials, the signals transmitted by the paging transceiver could
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`possibly trigger an explosion. The user therefore must tum his or her paging
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`transceiver off to ensure that it does not transmit any reply or acknowledgment
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`signals in response to a received page. Although it may be dangerous for the
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`paging transceivers to issue a reply signal in these situations, the signals
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`transmitted by the base station may at times be safely received by the paging
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`transceiver. Since the paging transceiver automatically issues a reply in response
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`to a received message, the paging transceiver must nonetheless be turned off so as
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`to not pose a risk to the user. During these times that the paging transceiver must
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`be turned off, the user unfortunately is unable to receive any page or message. A
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`need therefore exists for a paging transceiver that can notify a user of a message
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`without automatically generating a reply message or acknowledgment to the base
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`station.
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`SUMMARY OF THE INVENTION
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`The present invention solves the problems described above with methods
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`and systems for selective paging. A paging system notifies a paging transceiver
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`that a message has been received but does not initially transmit the associated
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`message. The user, upon being notified of the message, can then download the
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`entire message at a time convenient to the user, which allows the user to download
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`messages at less-expensive off-peak hours and allows the user to place the paging
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`transceiver at a location where it can easily receive the message and reply to the
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`message. Since the messages are not initially transmitted to the paging
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`transceiver, the paging transceiver can receive and store a greater number of pages
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`with minimal increase in the size of memory. Further, because entire messages are
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`not automatically transmitted and since the user can position the paging transceiver
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`to issue a sufficiently strong reply, traffic in the paging system can be controlled
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`and actually reduced.
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`The system may transmit some identifying information about the page to
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`the user without sending the entire message. For instance, the base station may
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`identify the type of message, such as email, voice, or text, and also indicate the
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`caller or other descriptive material about the message. The user can then
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`determine the priority of the messages and whether he or she wants to retrieve the
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`message, play the message, erase the message, store the message, forward, reply,
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`or otherwise act on the message. The user is also given control over the messages
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`stored remotely from the paging transceiver and can erase or store these messages
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`from the paging transceiver. The paging transceiver may have a timer for allowing
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`the user to program the paging transceiver to perform a desired function on a
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`message at a particular time.
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`The information initially sent to the user may also indicate the location of
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`the stored message. For instance, the system paging a particular paging
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`transceiver to notify it that a page has been received need not be the system
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`actually storing the content of the message. Instead, a plurality of systems may
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`store the contents of messages with one or more of the systems paging the paging
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`transceiver. The paging transceiver would be provided sufficient information on
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`the system storing the message so that it can communicate with this system. The
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`system paging the paging transceiver can therefore act as a clearinghouse for other
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`messaging systems by notifying a user of all messages received regardless of their
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`source or type.
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`Accordingly, it is an object of the present invention to provide pager
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`transceivers and methods for paging that conserve memory in paging receivers.
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`It is another object of the present invention to provide pager transceivers
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`and methods for paging that conserve valuable air time.
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`It is a further object of the present invention to provide pager transceivers
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`and methods for paging that provide users with remote control over their
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`messages.
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`It is yet another object of the present invention to provide pager
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`transceivers and methods for paging that allow users to select when and how
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`action should be taken on their messages.
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`It is yet a further object of the present invention to provide pager
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`transceivers and methods for notifying users of received messages.
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`It is also an object of the present invention to provide pager transceivers
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`and methods for providing control to users over message stored at remote
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`locations.
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`It is still another object of the present invention to provide pager
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`transceivers and methods that notify users of messages received from multiple
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`sources.
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`BRIEF DESCRIPTION OF THE DRAWINGS
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`The accompanying drawings, which are incorporated in and form a part of
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`the specification, illustrate preferred embodiments of the present invention and,
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`together with the description, serve to explain the principles of the invention. In
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`the drawings:
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`Fig. 1 is a block diagram of a paging transceiver according to a preferred
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`embodiment of the invention;
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`Fig. 2 is a more detailed block diagram of the transceiver in the paging
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`transceiver of Fig. 1;
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`Fig. 3 is a block diagram of a communication system according to a
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`preferred embodiment of the invention;
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`Figs. 4A and 4B are flow charts depicting an exemplary set-up routine for
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`establishing commlll1ications between the system of Fig. 3 and the transceiver of
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`Fig. 1;
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`Fig. 5 is a flow chart depicting a paging process;
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`Fig. 6 a flow chart depicting of process of notifying a paging transceiver of
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`an unread message;
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`Fig. 7 is a flow chart depicting a process of receiving a page at the paging
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`transceiver of Fig. 1;
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`Fig. 8 is a flow chart depicting a process of selecting a function at the
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`paging transceiver of Fig. 1;
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`Fig. 9 is a generic flow chart depicting a selective process performed at the
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`paging transceiver of Fig. 1 for executing a desired function;
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`Fig. lOis a block diagram of a paging system having multiple systems for
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`storing messages; and
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`Fig. 11 is a diagram of a data transmission for the system in Fig. 10.
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`DETAILED DESCRIPTION
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`Reference will now be made in detail to preferred embodiments of the
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`invention, non-limiting examples of which are illustrated in the accompanying
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`drawings. With reference to Fig. 1, a paging transceiver 100 according to a
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`preferred embodiment of the invention comprises an antenna 1, a transceiver 2, a
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`user interface 3, a controller 4, and a memory 5. The single antenna 1 is
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`preferably used for both receiving and transmitting signals, although the paging
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`transceiver 100 may comprise a separate antenna for transmitting signals and a
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`separate antenna for receiving signals.
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`The transceiver 2 is connected to the antenna 1 and is for transmitting
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`signals from the paging transceiver 100 and for receiving signals directed to the
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`paging transceiver 100. The signals that may be transmitted to, or received from,
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`the paging transceiver 100 include, but are not limited to, such signals as selective
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`call signals, command data signals, signals corresponding to a message, and
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`information data signals. The transceiver 2 may comprise a transceiver found in
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`two way pagers or mobile radios and preferably comprises a transceiver commonly
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`used in a portable mobile radiotelephone.
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`The transceiver 2 is connected to the user interface 3, which contains all
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`necessary input and output devices. The user interface 3 includes a microphone,
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`speaker, alert transducer, LED or LCD display, keypad, and necessary switches.
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`The user interface 3 may also contain other types of input/output devices
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`depending on the messaging application, such as a video display, camera, scanner,
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`a printer, or a voice recognition device. The user interface 3 is not limited to these
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`examples of user input/output devices but may comprise any input or output
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`device which allows or assists communication between the user and the paging
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`transceiver 100.
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`The transceiver 2 is connected to, and communicates with, the controller 4,
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`which preferably comprises a digital signal processor (DSP) 4. The memory 5 is
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`connected to the DSP 4 and is for storing messages or other types of information.
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`The memory 5 may comprise static RAM, Dynamic RAM, Flash RAM, or any
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`type of memory suitable for storing messages and allowing the retrieval of the
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`messages. The amount of the memory 5 is preferably at least 4 MB for voice or
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`text applications, although it may consist of a greater or lesser amount depending
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`upon the specific message type application.
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`The transceiver 2, as shown in more detail in Fig. 2, includes an antenna
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`interface 20 connected to the antenna 1 The antenna interface 20 directs signals
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`received from antenna 1 to a receiver section 21 of the paging transceiver 100 and
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`directs signals transmitted from a transmit section 24 to the antenna 1. The
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`antenna interface 20 is preferably a duplexer, however an antenna switch or other
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`device may be utilized to provide signal isolation between the receiver and
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`transmitter sections 21 and 24. Alternatively, if paging transceiver 100 includes
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`two antennas 1 with one for transmitting signals and the other for receiving
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`signals, the transceiver 2 would not require any type of antenna interface 20.
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`The receive section 21 includes a receiver 22 and a receiver frequency
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`synthesizer 23. The receiver 22 is connected to the antenna 1 through antenna
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`interface 20 and receives the signals directed to the paging transceiver 100. The
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`receiver frequency synthesizer 23, based on an input from a processor 27, selects
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`the frequency at which the receiver 22 receives signals. The received signals are
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`passed from the receiver 22 to the processor 27.
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`The transmit section 24 includes a transmitter 25 for receiving signals from
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`the processor 27. The transmit section 24 also includes a transmitter frequency
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`synthesizer 26 connected to the transmitter 25 which, based upon an input from the
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`processor 27, selects the transmit frequency for the transmitter 25. The signals
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`output by the transmitter 25 are supplied to the antenna interface 20 and then to the
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`antenna 1.
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`The processor 27 comprises a central processing unit (CPU) having internal
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`memory and switching capabilities. The CPU 27, for instance, comprises all
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`necessary RAM and ROM memory, signal and data switching circuitry, signal
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`processing circuitry, 1-0 Ports, and all standard program instructions and stored
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`options commonly utilized in portable cellular telephones. The standard cellular
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`telephone program instructions and CPU 27 may be obtained from a variety of
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`suppliers. For instance, the instructions may be obtained from Wireless Link Inc.
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`of Sunnyvale, California and the CPU 27 from GEC Plessey Semiconductor, Inc.
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`of Scotts Valley, California.
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`The DSP 4 includes necessary 1-0 and program memory and are commonly
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`utilized in cellular telephones. Any suitable DSP may be used in the paging
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`transceiver 100. Alternatively, the controller 4 may comprise another type of
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`electronic device, such as a codec or digital-to-analoglanalog-to-digital conversion
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`circuit or other type of modulator-demodulator including memory interface
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`circuitry coupled to message memory 5 for reading and writing of messages.
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`The transceiver 2 also preferably includes a delay circuit 28. The delay
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`circuit 28 may comprise a timer which informs the processor 27 of when a period
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`of time has expired. The timer, for instance, may expire at a certain time of day,
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`week, or month, or may expire a fixed period of time after a triggering event, such
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`as one hour after the event. The time at which the timer 28 expires is preferably
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`programmable through the user interface 3 and through processor 27.
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`Additionally, the timer 28 preferably comprises a plurality of timers for notifying
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`the processor 27 of when a plurality of different time periods have expired. Rather
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`than a timer, the delay circuit 28 may alternatively operate to delay the occurrence
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`of an event until a certain condition is satisfied. This condition, for instance, may
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`be the strength of received signals or the receipt of a specified signal. The purpose
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`of the timer 28 will become apparent from the description below.
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`With reference to Fig. 3, a system 30 according to a preferred embodiment
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`of the invention is interconnected to a base station 34, both of which are connected
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`to the Public Switched Telephone Network (PSTN) or to other telephone company
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`equipment 35. The system 30 comprises a paging terminal controller 31 which
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`may comprise a controller circuit and associated memory having a database of
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`subscriber listings and corresponding selective call address fields. The paging
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`terminal controller 31 communicates with storage and retrieval unit 32 and
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`correlates messages with subscriber listings. The storage and retrieval unit 32 may
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`comprise a CPU or control circuit, message information and program memory,
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`memory interface circuitry and a DSP with appropriate operational code for
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`storage and retrieval of the desired messages. The input/output controller 33
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`contains all necessary input and output circuitry such as encoders and decoders,
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`modems and required routing and control circuitry for communicating with the
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`paging terminal controller 31, the storage and retrieval unit 32, the PSTN 35, and
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`the base station 34.
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`A call setup routine 40 for establishing communication between the system
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`30 and base station 34 will now be described with reference to Figs. 4A and 4B.
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`At step 41, a connection, such as a telephone connection, is routed through the
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`PSTN 35 or in the case of paging transceiver 100 the switch 36, to the input/output
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`controller 33. The input/output controller 33 determines at step 42 whether the
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`connection is with an automated signaling device or with a person. If the
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`connection is with a person, then at step 48 the storage and retrieval unit 32 is
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`activated to produce one or more voice responses during the call in order to guide
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`the person throughout the process.
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`If, at step 42, the input/output controller 33 determines that the call is from
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`a device, such as a paging transceiver 100 or computer terminal, data is exchanged
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`between the paging transceiver 100 and system 30 at step 43. The type of data that
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`may be exchanged includes, but is not limited to, the following types of data:
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`identification data, command data, and information data. The data supplied from
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`the PSTN 35 may also be exchanged at step 43 with this data including data for
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`identifying the caller and subscriber, such as, for example, Caller ID and DNIS
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`(Dialed Number Identification Service). Additionally, the data may be extracted
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`from the base station 34. For example, the location of the paging transceiver 100
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`may be determined from a home location registry (HLR) and the HLR data may be
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`utilized by the system 30 in order to determine the location of the paging
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`transceiver 100, as opposed to having the paging transceiver 100 supply the
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`location information to system 30.
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`After data is exchanged at step 43, the system 30 determines at step 44
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`whether an error occurred during the transmission between the system 30 and
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`paging transceiver 100. If an error did occur, then at step 47 the process ends and
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`the paging transceiver 100 is informed of the error. The error is preferably
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`presented to the user in the form of status information produced at the user
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`interface 3, such as with an alert tone or visual display on the LED or LCD
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`display. An error may include, but is not limited to, the following errors: "system
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`busy," "wrong ID," or "bill over due." If no error is detected, as determined by the
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`system 30 at step 44, a function is enabled and executed at step 45. The function,
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`as will be described in greater detail below with reference to Fig. 8, may be
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`selected by the user from a group of available functions. At step 46, housekeeping
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`functions are performed both at the paging transceiver 100 and at the system 30
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`and the call is terminated at step 47.
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`If the call is from a person as determined at step 42, then the caller is
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`provided with a voice response at step 48 and, with reference to Fig. 4B, the caller
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`is then verbally prompted at step 49 to enter information. At step 50, the caller
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`sends data to the system 30, such as by pressing the telephone keypad to generate
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`DTMF tones. The data that may be sent by the caller includes, but is not limited
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`to, ID code, pass code, mail box number, and subscriber number. The system 30
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`may respond to voice commands from a caller by utilizing a readily available
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`voice recognition system, such as those presently in use by the telephone company
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`to except collect calls. At 51, the system 30 determines whether an error has
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`occurred. If an error is detected, the caller may be given an opportunity to correct
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`the error or, as shown, the process may end at step 56. Ifno error was detected by
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`the system 30 at step 51, a message, such as a voice message, is recorded and
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`stored in the storage and retrieval unit 32 at step 52. At step 53, the system 30
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`determines whether a return receipt or a reply message is requested. If a return
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`receipt or reply message is requested, the return address is entered by the caller or
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`optionally issued by the system 30 and is stored by the system 30 in the storage
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`and retrieval unit 32 at step 54. The system 30, for instance, may detect the
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`address signal of the incoming call and, by default, store this number as the return
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`address. After the return address is stored at step 54 or if a return address is not
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`requested, the stored message is cross referenced to selective call data
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`corresponding to the intended paging transceiver 100 at step 55. Also at step 55, a
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`flag is set in a transmission stack file at the paging terminal controller 31 for
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`subsequently transmitting selective call signals representative of the selective call
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`data to the targeted paging transceiver 100. Housekeeping is performed by the
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`system 30 and the call ends at step 56.
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`The base station 34, as shown in Fig. 3, comprises a switch 36, a
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`transceiver antenna 37, and a transceiver base station 38. In response to a received
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`message, the system 30 passes control information to switch 36 for setting up a
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`page call. The switch 36, for instance, may be a mobile telephone switching office
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`(MTSO) for interfacing to the transceiver base station 38. In the send page mode,
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`selective call signals having an address associated with the paging transceiver 100
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`are transmitted. The address may be an address code for a paging transceiver, a
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`mobile telephone number (MIN) for a mobile radiotelephone, or type of
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`identifying infonnation for a communication device.
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`Command data and infonnation data may also be communicated from the
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`system 30 to the paging transceiver 100 through the base station 34. The
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`command data and infonnation data shall hereinafter be referred to as CI data,
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`examples of which include the following: paging transceiver location, forward
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`message, retrieve message, reply to message, paging transceiver ID, message
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`identifiers, retrieval instructions, save message, erase message, message type,
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`message length, time/date message received, system 30 ID, system 30 location,
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`message address, message location, battery life, message identifier, format code,
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`compression type, message age, message priority, alert codes, energy saving
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`commands, memory status, program data, provisioning data, acknowledgment data
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`and requests, function codes, sender name, current time, number of messages,
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`mailbox number, phone number, return address, alpha numeric short messages,
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`general command requests, group calls, and signal strength.
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`The address and command data and infonnation may be transmitted over
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`any suitable communication system. For instance, the data may be communicated
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`over a paging system, a cellular system having short message service capabilities,
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`such as GSM-SMS, a Cellular Digital Packet Data (CDPD) system, Personal
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`Communications Services, or any other type of mobile radiotelephone system or
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`communication system. Furthermore, the paging transceiver 100 preferably is able
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`to communicate over more than one system, such as with both a paging network
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`and a mobile radiotelephone network.
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`With reference to Fig. 5, a flow diagram 60 for performing a page call is
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`shown. At step 61, the system 30 locates the current message flag from its
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`transmission stack within paging terminal controller 31 and communicates with
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`base station 34 for setting up a page call. The base station 34 transmits selective
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`call signals and CI data to the targeted paging transceiver 100. At step 62, the
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`system 30 determines whether an acknowledgment (Ack) was received from the
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`paging transceiver 100 indicating that the page call was received. If an
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`acknowledgment was not received, then at step 70 the system 30 determines
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`whether an acknowledgment is a system 30 option. If an acknowledgment is
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`required, then at step 71 the system 30 assigns the page call a priority in the
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`transmission stack and eventually returns to step 61 for re-transmission. If the
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`acknowledgment is received at step 62, the system 30 sets an acknowledgment flag
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`(Ack flag) corresponding to the stored message.
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`If an acknowledgment is not a system requirement, as determined at step
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`70, or after posting the acknowledgment flag at step 63, the system 30 sets a timer
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`at step 64 and waits a period of time before proceeding to step 65. At step 65, the
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`paging terminal controller 31 determines if the stored message has been read. If
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`the message has been read, then at step 66 the system 30 posts a read flag in the
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`subscriber data base to indicate that the message was delivered and read and at step
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`67 the process ends.
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`If, at step 65, the message had not been read, then at step 68 the system 30
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`determines the priority of the message and proceeds to step 69. If the priority is
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`high, as determined at step 69, then at step 61 the page call is returned to the
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`transmission stack at the designated priority level for re-transmission. If, on the
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`ATLLlBOl 463360.1
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`17
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`other hand, the priority is not high as determined at step 69, then the message has a
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`low priority and the process ends at step 67.
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`An alternate routine 80 for notifying a paging transceiver 100 that an
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`unread message is waiting is shown in Fig. 6. At step 81, the paging terminal
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`controller 31 sorts through subscriber listings which have a corresponding unread
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`and unnotified message in the storage and retrieval unit 32 and sends a page
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`request to base station 34. At step 82, the switch 36 checks a home location
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`registry (HLR) to determine the registered location and status of the remote paging
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`transceiver 100. A page call is processed by transmitting selective call from
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`transceiver base station 37 at step 82. If a page acknowledgment is desired for
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`verification that the paging transceiver 100 recipient received the selective call
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`signals, an Ack signal is manually or automatically transmitted from the paging
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`transceiver 100 to base station 34 for storage in the subscriber database of paging
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`terminal controller 31 at step 82.
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`At step 83, a notified flag is set in the subscriber data base corresponding to
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`the unread message stored in the storage and retrieval unit 32 and the paging
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`process for the current unread message ends at step 84. If at step 82 an
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`acknowledgment signal was not received, the message is assigned a new priority
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`and the process is subsequently repeated. Optionally, a plurality of priorities may
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`be assigned to acknowledged and not acknowledged unread messages so that the
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`paging transceiver 100 is sent a number of calls until the message is read by the
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`subscriber.
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`In the preferred embodiment, the base station 34 is part of a mobile
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`ATLLIBOI 463360.1
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`18
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`radiotelephone network and the paging transceiver 100 is paged over the
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`designated paging channel or the control channels of the network. In addition to
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`paging the paging transceiver 100, the short messages or other data transmitted to
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`the paging transceiver 100 is also preferably transmitted over the paging channel
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`or control channels. Although the paging is preferably performed through a
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`mobile radiotelephone network, the selective call signals may alternatively be
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`routed to a paging system for transmitting an address code and CI data over an
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`independent paging transmitter. In such a configuration, the paging transceiver
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`100 may be configured to have a separate paging receiver or transceiver
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`compatible with the paging transmitter or paging transceiver. Since radio pager
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`devices require much less energy than portable cellular telephones, a paging
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`transceiver 100 configured with a low energy paging receiver would reduce energy
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`required for receiving selective call signals and allow high energy circuitry of the
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`paging transceiver 100 to be turned off until the user needs to retrieve or transmit
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`messages. Other variations and modifications will be apparent to those skilled in
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`the art.
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`A process 90 for receiving messages at a paging transceiver 100 is shown
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`in Fig. 7. A selective call signal including an address is received by receive
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`section 21 of the transceiver 100 at step 91. At step 92, the demodulated signal is
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`processed by the CPU 27 to compare the received address with an address code
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`stored in the CPU 27 memory_ If the received address code does not match the
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`stored address, flow returns to step 91 and the transceiver 100 continues to monitor
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`transmissions for its address. When the address corresponds to the pre-stored
`