Abstract:
A pager system which enables users to avoid having to pay monthly service charges. The pager system is particularly useful in that it can be coupled easily to an existing local area network (LAN) to provide paging capabilities within a local area (i.e., a campus) such as a building or set of buildings. Thus, businesses, universities, etc., who currently have a LAN or contemplate installing one can couple the pager system to the LAN in order to provide localized paging. Such localized paging is provided without the need to pay monthly service charges to paging service providers. A business, university, etc., incurs primarily only an initial cost to purchase the pager equipment. Therefore, the present system represents a substantial cost savings compared to WAN based paging service providers for those desiring localized paging.

Description:
TECHNICAL FIELD 
     The present invention relates generally, as is indicated, to a campus area pager system. More particularly, the invention relates to a pager system suitable for introducing paging capabilities over new and existing local area networks (LANs). 
     BACKGROUND OF THE INVENTION 
     Pager (or paging) systems are known in the art. Subscribers to such systems carry a personal paging unit (hereinafter referred to as a “pager”) which includes a radio frequency (RF) receiver for receiving one-way information. For example, a short alpha-numeric message received by the pager can alert the subscriber to call the office, meet a customer, etc. The pager may be programmed to emit a beeping noise or mechanically vibrate to notify the subscriber in the event a message is received. The subscriber can then read the message by pressing one or more buttons on the pager so as to display the message on an alpha-numeric display. 
     Paging services are typically provided by a paging service provider which has a number of RF transmitting stations for providing paging coverage over a large geographic area. The transmitting stations are interconnected via a wide area network (WAN) which enables subscribers to receive information input, for example, via a telephone network. 
     There are, however, a number of drawbacks associated with conventional pager systems such as those discussed above. For example, the paging service providers typically charge subscribers a monthly service charge. Thus, in addition to having to purchase the pagers themselves, subscribers are faced with ongoing monthly service charges which quickly add up to a significant amount of money. The aggregate of such ongoing service charges oftentimes exceed the cost of the pagers themselves. Furthermore, even if the subscribers need the paging service only within a small geographic region, e g., within a single building or set of buildings, the same monthly service charges typically apply. 
     In addition, such pager systems oftentimes do not provide reliable service. For example, the transmitting stations are typically located some distance away from the pagers to which information is to be transmitted. Interference associated with transmitting signals over long distances and through building infrastructures often causes “dead spots” in which pagers cannot receive information. This can result in important page messages being lost or otherwise not received at least until such time as the pager moves to a location which is not within a dead spot and the messages are resent. 
     In view of the aforementioned drawbacks associated with conventional pager systems, there is a strong need in the art for a system which eliminates the need to subscribe to a paging service provider and pay monthly service charges. Moreover, there is a strong need in the art for a system which does not rely on a WAN based network. In particular, there is a strong need for a pager system which does not suffer from lost or delayed messages due to frequent “dead spots”. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a pager system which enables users to avoid having to pay monthly service charges. The pager system is particularly useful in that it can be coupled easily to an existing local area network (LAN) to provide paging capabilities within a local area (i.e., a campus) such as a building or set of buildings. Thus, businesses, universities, etc., who currently employ a LAN or contemplate installing one can couple the pager system of the present invention to the LAN in order to provide localized paging. Such localized paging is provided without the need to pay monthly service charges to paging service providers. As a result, the present invention affords a business, university, etc., the benefit of avoiding monthly service charges and only incurring primarily the initial cost of purchasing the pager equipment. Hence, the present invention represents a substantial cost savings compared to WAN based paging service providers for those desiring localized paging. 
     Moreover, since the pager system can be connected to an existing LAN, it is easy to eliminate potential “dead spots” by connecting one or more transmitting stations to the LAN. LANs are typically designed to extend to all areas of a building or campus, for example. Accordingly, transmitting stations can be easily connected at different points on the LAN to provide complete pager access throughout the local area. 
     According to the preferred embodiment which is discussed more fully below, the pager system of the present invention includes an automated pager server which is directly coupled to the LAN for receiving information from devices on the LAN intended to be transmitted to a pager. The pager server transmits the information to a transmitting station which is also coupled to the LAN and which is designated for transmitting information via a wireless link to the pager. Information to be transmitted to a pager may originate from working terminals (e.g., personal work stations) connected to the LAN as well as other devices. The pager system also includes a telephone interface for connecting the pager server to a local PBX and local telephone network so that information received via incoming telephone calls can be forwarded to pagers within the system. In addition, the telephone interface couples the pager server to a conventional WAN based paging service provider so that information from outside the LAN can be transferred to the pagers within the pager system. Similarly, page requests from within the pager system can be routed to the paging service provider in the event such service is necessary. 
     According to one particular aspect of the invention, a campus area pager system is provided, including: a local area network (LAN) having a system backbone; at least one base station coupled to the system backbone, each of the at least one base station including a wireless communication section; and at least one paging device for receiving page information from the system backbone via the wireless communication section. 
     According to another aspect of the invention, a campus area pager system is provided, including: a local area network having a system of the at least one base station including a wireless communication section; backbone via the wireless communication section, each of the plurality of paging devices having a respective pager identification number; and a pager request information including a page message and one of the pager identification numbers, and for transmitting the page information on the system backbone in order to be received by the at least one base station and transmitted via the wireless communication section to the paging device 
     In accordance with yet another aspect of the invention, a network system is provided, including: a local area network (LAN) having a system backbone and a plurality of devices coupled to the system backbone for performing non-paging related activities via communications on the system backbone; a plurality of base stations coupled to the system backbone, each of the plurality of base stations including a wireless communication section; a plurality of paging devices for receiving communications from the system backbone via the wireless communication section of at least one of the plurality of base stations, each of the plurality of paging devices having a respective pager identification number; and a pager server coupled to the system backbone, the pager server for receiving page request information including a page message and one of the pager identification numbers, and for transmitting the page information on the system backbone in order to be received by the at least one base station and transmitted via the wireless communication section to the paging device corresponding to the one of the pager identification numbers. 
    
    
     To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of a cellular communication system including a campus area pager system in accordance with the present invention; 
     FIG. 2 is a schematic diagram showing an exemplary format of an information packet of the type used for transmitting information within the cellular communication system of FIG. 1 in accordance with the present invention; 
     FIG. 3 is a block diagram of a mobile terminal within the cellular communication system of FIG. 1 in accordance with the present invention; 
     FIG. 4A is a block diagram of a pager in accordance with the present invention; 
     FIG. 4B is a perspective view of the pager represented in FIG. 4A; 
     FIG. 5 is a block diagram of a base station in accordance with the present invention; 
     FIG. 6 is a block diagram of a pager server and telephone interface included within the pager system of FIG. 1 in accordance with the present invention; 
     FIG. 7 is a system flowchart suitable for programming the pager system to receive a page request from outside the cellular communication system, and to forward the information included therein to the appropriate pager within the system; 
     FIG. 8 is a schematic diagram representing the contents of an exemplary page request information packet transmitted by the pager server of FIG. 6 in accordance with the present invention; 
     FIG. 9 is a system flowchart suitable for programming the pager system to receive a page request from a device on a local area network within the cellular communication system, and to forward the information included therein to the appropriate pager within the system; 
     FIG. 10 represents the contents of a look-up table included in memory within the pager server for identifying the network recognizable address of valid pagers within the system in order to forward pager information thereto; 
     FIG. 11 is a system flowchart suitable for programming a base station within the system to transmit a message to a specified pager in accordance with the present invention; 
     FIG. 12 is a system flowchart suitable for programming the system to carry out a registration procedure among the mobile terminals and pagers with the respective base stations; and 
     FIG. 13 is a system flowchart suitable for programming the system to carry out a registration update of the pager server look-up table. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The campus area pager system of the present invention will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. 
     Referring initially to FIG. 1, the campus area pager system of the present invention is shown incorporated within a cellular communication system generally designated  100 . The cellular communication system  100  is centered around a local area network (LAN)  102 . The LAN  102  consists in part of one or more base stations  108  connected together via a hardwired data communication path, commonly referred to as a system backbone  104 . The cellular communication system  100  may be of the type utilized in retail stores or warehouses, for example. Such systems are useful for tracking inventory and replenishing stock. Employees may enter inventory information using a hand held or portable mobile terminal  106  which can be carried throughout the store or warehouse. The information entered into the mobile terminals is then transferred to the system backbone  104 , for example, by way of a base station  108  which is coupled to the system backbone  104 . In manufacturing facilities, the cellular communication system  100  can be useful for tracking parts, completed products and defects. In a medical environment, the cellular communication system  100  is useful for reducing the time needed to fill out forms and eliminate inaccuracies by allowing medical personnel to transmit data directly from a mobile terminal  106  carried by the medical personnel. Such data can then be evaluated at a central location on the LAN  102 . 
     Cellular communication systems in which mobile terminals  106  are used to track inventory, medical information, etc., are known in the art, and are commonly used in many different businesses, retail stores, hospitals, etc. The cellular communication system  100  differs from conventional systems, however, in that it also includes a campus area pager system  110  for providing paging services within the cellular communication system  100 . Specifically, the pager system  110  includes a pager server  112  directly coupled to the system backbone  104 , and a plurality of paging devices  114  (“pagers”) for receiving pages. Mobile terminals  106  could also be configured to transmit or receive pager communications as is discussed in more detail below. Each pager  114  is designed to be carried by a respective user as the user moves about a geographic region  116  covered by the communication system  100 . Someone wishing to contact a particular user sends a page request to the pager server  112 . As is described more fully below, the pager server  112  receives page requests from the LAN  102  or a telephone interface  125  and directs the request to the appropriate pager  114 . The base station  108  with which the pager  114  is registered then proceeds to transmit the page message to the pager  114  via an RF transmitter. The actual size of the region  116  depends on the range of the devices in the particular communication system  100 , but typically the region  116  will encompass an entire building, a set of buildings, or some other local area. 
     A feature of the present invention is that the pager system  110  is designed such that it can be connected to virtually any existing or newly created LAN such as the LAN  102  included in the cellular communication system  100 . By adding a pager server  112  and pagers  114  or mobile terminals  106  capable of handling pager functions, localized paging service is available at relatively low cost and without needing to pay ongoing monthly service charges associated with WAN based paging service providers. When adding a pager server  112  and pagers  114  to an existing LAN other than a cellular communication system  100 , it may be necessary to also add one or more base stations  108  which are connected to the system backbone  104 . Again, however, this represents a relatively small up-front cost for equipment and avoids the monthly fees associated with paging services. 
     Describing now the communication system  100  in more detail, the system backbone  104  may be made up of a twisted pair cable, shielded coaxial cable or fiber optic lines, for example. Connected to the system backbone  104  are one or more of the base stations  108 . As is discussed in more detail below in connection with FIG. 5, each base station  108  is capable of transmitting and receiving information wirelessly and exchanging such information with the system backbone  104 . Each base station  108  wirelessly communicates with other devices in the system  100  via an omnidirectional antenna  120  which provides for a generally spherical area of coverage within the region  116 . For example, a base station  108  may transmit and receive information by way of a radio signal to/from one or more mobile terminals  106  and/or pagers  114  within the system  100  as is described in detail below. In addition, if wireless base stations  108 ′ (with their corresponding antenna  120 ′) are utilized to extend the area of coverage of the base stations  108 , as is known, the base stations  108  and  108 ′ wirelessly communicate with each other. Directional yagi type antennas or other types of antennas could also be used in place of the antenna  120  as will be appreciated. 
     The base station  108  with its corresponding antenna  120  is able to transmit and receive RF communications within a respective geographic cell within the region  116 . The base stations  108  are preferably positioned throughout the region  116  on the system backbone  104  such that their combined cell area coverage allows for full wireless communication access with the pagers  114  and mobile terminals  106  throughout the region  116 . Thus, for example, users may carry a pager  114  throughout an entire building, set of buildings, etc., and always remain within radio contact of one of the base stations  108  in order to be able to receive a page. Similarly, users having a mobile terminal  106  can transmit and/or receive information from the LAN  102  via a corresponding base station  108 . 
     As is described below in connection with FIG. 12, the pagers  114  and mobile terminals  106  go through a process of registering and deregistering with base stations  108  as they move about the region  116  from one cell to another. When a pager  114  or mobile terminal  106  is powered up, it “registers” initially with a base station  108 . However, as the location of the pager  114  or mobile terminal  106  changes, the pager  114  or mobile terminal  106  may register with a new base station  108 , thereby resulting in a deregistration with the previous base station  108 . Furthermore, deregistration will sometimes occur if there is no communication between the pager  114  or mobile terminal  106  and its corresponding base station  108  within a predetermined period of time. In any event, movement of the pagers  114  and mobile terminals  106  between cells covered by different base stations  108  is accounted for in order that information can be provided reliably therebetween. 
     The pager server  112  maintains a look-up table as discussed below which includes a pager identification (ID) number of each pager  114  in the system together with the corresponding network recognizable “identification address” of the pager  114 . In the event the LAN  102  utilizes source routing for transmitting information packets, the pager server  112  also keeps track in its look-up table of which pagers  114  are registered to which base stations  108  as described below in relation to FIGS. 10 and 13. Upon receiving a page request, the pager server  112  determines which base station  108  a particular pager is currently registered to. The pager server  112  then routes a page request information packet to the base station  108  which in turn transmits the page to the pager  114 . In the event non-source routing is utilized, upon receiving a page request for a particular pager, the pager server  112  simply addresses the page request information packet to the pager  114  based on the identification address in the look-up table. The base station  108  with which the particular pager  114  is registered ultimately receives the page request packet and transmits the packet to the pager  114 . Thus, despite which particular cell the pager  114  is currently registered to, the page is transmitted via the appropriate base station  108 . The particular manner in which the pager server  112  handles communications relating to the pagers  114  is discussed below with respect to FIGS. 7-11. 
     With reference still to FIG. 1, the pager system  110  further includes a telephone interface  125  coupled to the pager server  112 . The telephone interface  125  interfaces the pager server  112  to a local public telephone network via a local PBX, for example. Such telephone connection can be used to receive page requests from outside the cellular communication system  100 . In addition, or in the alternative, access to the local public telephone network allows page requests from within the communication system  100  to be routed outside to a paging service provider as is also discussed below. 
     A host computer  130  is also connected to the system backbone  104 . The host computer  130  serves as the controller for the communication system  100  as is conventional. In addition, the host computer  130  generally serves as a central storage medium for system data, etc., as is also conventional. The LAN  102  includes other devices (generally represented at  132 ) such as work terminals or stations, printers, facsimile devices, data storage facilities, etc., connected to the system backbone  104 . As will be appreciated, the pager system  110  of the present invention has utility with virtually any LAN, and is not necessarily limited to the cellular communication system  100  shown in FIG.  1 . 
     Referring now to FIG. 2, information is transmitted between the various devices in the communication system  100  preferably in the form of packets  150 . As shown, each packet  150  includes a synchronization field  152  which includes synchronizing bits which allow a device receiving the packet an opportunity to “lock on” to the packet as is conventional. A header field  154  follows the synchronization field  152  and includes information such as the length and type of the packet. For example, the header field  154  may indicate whether the packet is a type which requires a response from the receiving device. A source address field  156  follows the header field  154  and includes the address of the device from which the packet  150  originated. Following the source address field  156 , the packet  150  includes a destination address field  158  which holds the address of the device to which the packet  150  is ultimately destined. In the event the LAN  102  utilizes source routing whereby a device transmitting a packet identifies the particular route along the LAN  102  on which the packet is to be transmitted, such information is included in a source routing field  159  included in the packet  150  as is conventional. In a non-source routed LAN  102 , the source routing field  159  is omitted as packets are broadcast throughout the entire network absent specified routing. In the preferred embodiment, source routing as conventionally known is employed, but certainly non-source routing could also be used in a conventional manner. A data field  160  in the packet  150  includes various information intended to be communicated to the receiving device. The packet  150  ends with a cyclical redundancy code (CRC) field  162  which serves as an error correcting field according to conventional techniques whereby a receiving device can determine if it has properly received the packet  150 . 
     FIG. 3 is a block diagram representing the basic structure of the mobile terminals  106  according to the exemplary embodiment. Each mobile terminal  106  includes a processor  170  which can be programmed to control and to operate the various components within the mobile terminal  106  in order to carry out the various functions described herein. The processor  170  is coupled to an operator input device  172  which allows an operator to input data to be communicated to the LAN  102  such as inventory data, patient information, etc. This information may be sent to the host computer  130  which serves as a central data location, for example, or to a cash register connected to the system backbone  104 , as another example, for providing price information. Furthermore, the input device  172  allows an operator to input a page request to be sent to a pager  114  or a mobile terminal  106  serving as a pager via the pager server  112  as discussed in more detail below. The input device  172  can include such items as a keypad, touch sensitive display, etc. The mobile terminal  106  also may include a bar code scanner  173  coupled to the processor  170  for providing another form of data input. A display  174  is also connected to and controlled by the processor  170  via a display driver circuit  175 . The display  174  serves as a means for displaying information stored within the mobile terminal  106  and/or received over the system backbone  104  via a base station  108 . The display  174  can be a flat panel liquid crystal display with alphanumeric capabilities, for example, or any other type of display as will be appreciated. 
     A memory  176  is included in each mobile terminal  106  for storing program code executed by the processor  170  for carrying out the functions described herein. The actual code for performing such functions could be easily programmed by a person having ordinary skill in the art of computer programming in any of a number of conventional programming languages based on the disclosure herein. Consequently, further detail as to the particular code has been omitted for sake of brevity. The memory  176  also serves as a storage medium for storing information packets  150  received from or intended to be transmitted to a base station  108  as discussed herein. 
     Each mobile terminal  106  also includes its own RF section  178  connected to the processor  170 . The RF section  178  includes an RF receiver  182  which receives RF transmissions from a base station  108  and via an antenna  184  and demodulates the signal to obtain the digital information modulated therein. An example of a suitable RF receiver  182  for use in the mobile terminal  106  (as well as the base stations  108  and pagers  114 ) is the Model 025 Direct Sequence Spread Spectrum Radio Module, which is commercially available from Aironet Wireless Communications, Inc. of Akron, Ohio. 
     The RF section  178  also includes an RF transmitter  186 . In the event the mobile terminal  106  is to transmit information to the LAN  102  in response to an operator input at input device  172 , for example, the processor  170  forms within the memory  176  an information packet  150  (FIG. 2) including data together with a source address (i.e., the address of the particular mobile terminal  106  sending the information) and a destination address (e.g., the host computer  130  or pager server  112 ). The information packet is then delivered to the RF transmitter  186  which transmits an RF signal with the information packet modulated thereon via the antenna  184  to the base station  108  with which the mobile terminal  106  is registered. 
     An exemplary mobile terminal  106  which is configured to operate in accordance with the description herein is the commercially available Model PTC-960 portable computer with Model 025 Direct Sequence Spread Spectrum Radio Module. Such unit is available from Aironet Wireless Communications, Inc. mentioned above. 
     FIG. 4A represents the configuration of each pager  114  according to the exemplary embodiment. Each pager  114  includes a processor  195  programmed to control the various operations of the pager  114  described herein. The processor  195  is coupled to a memory  197  such as a RAM or combination RAM and ROM which serves in part to store the program code executed by the processor  195  to carry out the various functions described herein. The processor  195 , as with all the processors described herein, can be programmed to carry out its respective functions using conventional techniques which will be apparent to those having ordinary skill in the art based on the present specification. As a result, additional detail has been omitted. The memory  197  also serves to store other data such as information received via a page request, for example. 
     Connected to an output of the processor  195  is a display driver circuit  199  which drives a liquid crystal display (LCD)  201 , for example. In the exemplary embodiment, the LCD  201  is capable of displaying up to two lines of alpha-numeric characters with each line having up to 20 characters. Nevertheless, other type displays are certainly within the intended scope of the invention. A beep/vibrate selector switch  203  is connected to an input of the processor  195  which allows a user to set the switch  203  to indicate whether the user is to be notified of a received page by either a beeping sound or a mechanical vibration. Provided the switch  203  is in a beep position, a speaker  205  coupled to an output of the processor  195  is controlled to emit a beeping sound when a page is received as determined by the processor  195 . If the switch  203  is in a vibrate position, an electro-mechanical vibrator  207  is activated by the processor  195  when a page is received. 
     A view button  209  coupled to an input of the processor  195  allows the user to view messages received by the pager  114 . For example, the processor  195  is programmed such that if the view button  209  is pressed once by the user, the most recent message which has been received will be displayed by the processor  195  on the LCD  201 . If the view button  209  is pressed again within a short time, the user can scroll through a number of recently received messages that have been stored in the memory  197 . Furthermore, if the view button  209  is pressed while the speaker  205  or the vibrator  207  is active (indicating a new page has been received), the pressing of the view button  209  will serve to inactivate the beeping or vibration. 
     The pager  114  also includes an RF section  211  similar to the RF section  178  of the mobile terminals  106  and having an RF transmitter  214  and an RF receiver  216 . Signals are received by the RF receiver  216  via an antenna  218 . As mentioned above, the communications between the respective devices occur in the form of packets and the RF receiver  216  is designed to demodulate and decode any received signals using conventional techniques in order to obtain the information included therein. The data which is received by the RF receiver  216  is then provided to the processor  195  for further processing in order to be displayed, for example. The packets received by the RF receiver  216  may be page requests sent by a base station  108  as discussed below. Alternatively, for example, the packets may be registration information from one or more of the base stations  108  as discussed below with respect to FIG.  12 . 
     Information to be transmitted by the pager  114  is provided by the processor  195  to the transmitter  214  which in turn encodes and modulates the information onto an RF carrier signal. Such information which is transmitted is limited primarily to registration information which enables the pager  114  to register and deregister with different base stations  108  as the pager  114  roams from one cell location to another. In the preferred embodiment, the pager  114  is dedicated specifically to serving as a device for receiving pages. The pager  114  is not intended to provide the user with any other type of communications and hence can be built using relatively few components. 
     FIG. 4B is a perspective view of the pager  114 . The pager  114  includes a pocket-sized housing  225  in which the components shown in FIG. 4A are contained. The LCD  201  is exposed at the top portion of the housing  225 . The view button  209  and beep/vibrate selector switch  203  are mounted on the side of the housing  225  for easy access. A belt clip  227  is integrally molded at an end  229  to the housing  225 , and together with the housing  225  is preferably made of high-strength, lightweight plastic. The belt clip  227  allows the user to clip the pager  114  to his or her belt as will be appreciated. 
     Referring now to FIG. 5, a block diagram representative of each base station  108  is shown. Each base station  108  is connected to the system backbone  104  via a connector  240  such as a DB-9 or RJ-45 connector. The connector  240  is connected to the system backbone  104  at one end and to a network adapter transceiver  252  included in the base station  108  at the other end. The network adapter transceiver  252  is configured according to conventional network adapter transceiver techniques to allow the base station  108  to communicate over the system backbone  104 . The network adapter transceiver  252  is also connected to an internal bus  254  included within the base station  108 . The base station  108  further includes a processor  256  connected to the bus  254  for controlling and carrying out the operations of the base station  108 . The processor  256  may include any of a variety of different microprocessors, such as the Motorola 68360 (25 MHz) or Intel 80386 microprocessors. 
     The base station  108  also includes a memory  258  connected to the bus  254 . The memory  258  stores program code executed by the processor  256  to control the other elements within the base station  108  to carry out the functions described herein. It will be readily apparent to a person having ordinary skill in the art of computer programming how to program the processor  256  and the other elements within the base station  108  to carry out the operations described herein using conventional programming techniques based on the flowcharts and descriptions provided herein. As a result, additional detail as to the specific program code has been omitted. The memory  258  also serves to buffer packets of information such as those received over the system backbone  104  or those transmitted to or received from the mobile terminals  106  or the pagers  114 . Moreover, the memory  258  functions to store information tables maintained by the processor  256  including information such as a list of the mobile terminals  106  and pagers  114  which are currently registered with the base station  108 . 
     Also connected to the bus  254  is an RF section  260  included in the base station  108 . The RF section  260  includes the aforementioned antenna  120  for receiving radio signals from and transmitting radio signals to mobile terminals  106  and pagers  114  within the cell area of the base station  108 . Information transmitted from a mobile terminal  106  or pager  114  is received via the antenna  120  and is processed by an RF receiver  262  which demodulates and decodes the signal and converts the information to a digital signal having the aforementioned packet format. The processor  256  in the base station  108  inserts source routing information into the source routing field of the packet received from the mobile unit, if needed. Thereafter, the processor  256  stores the packet in the memory  258  until such time as the base station  108  is able to transmit the information packet onto the system backbone  104  via the network adapter transceiver  252  and connector  240 . 
     Information packets which are transmitted to the base station  108  via the system backbone  104  for transmission to a mobile terminal  106  or pager  114  are received by the network transceiver  252 . The processor  256  controls an RF transmitter  264  included in the RF section  260 , the RF transmitter  264  also being connected to the bus  254 . The processor  256  causes the RF transmitter  264  to modulate an RF signal using spread spectrum techniques, for example, which in turn carries the information packet to the appropriate mobile terminal  108  or pager  114 . Exemplary hardware for carrying out the above-described basic functions of transmitting and receiving data between the system backbone  104  and one or more mobile terminals  108  or pagers  114  is found in the ARLAN 631® Token Ring Access Point, which is commercially available from Aironet Wireless Communications, Inc., Akron, Ohio. 
     Turning now to FIG. 6, the hardware configuration of the pager server  112  and telephone interface  125  is shown. Similar to the base station  108  shown in FIG. 5, the pager server  112  is connected directly to the system backbone  104  via a connector  288  such as a DB-9 or RJ-45 connector. The connector  288  is connected to the system backbone  104  at one end and to a network adapter transceiver  290  included in the pager server  112  at the other end. The network adapter transceiver  290  is configured according to conventional network adapter transceiver techniques to allow the pager server  112  to communicate over the system backbone  104 . The network adapter transceiver  290  is also connected to an internal bus  294  included within the pager server  112 . The pager server  112  further includes a processor  300  connected to the bus  294  for controlling and carrying out the operations of the pager server  112  described herein. The processor  300  may include any of a variety of different microprocessors, such as the Motorola 68360 (25 MHz) or Intel 80386 microprocessors. 
     The pager server  112  also includes a memory  302  connected to the bus  294 . The memory  302  stores program code executed by the processor  300  to control the other elements within the pager server  112  and to otherwise carry out the functions described herein. It will be readily apparent to a person having ordinary skill in the art of computer programming how to program the processor  300  and the other elements within the pager server  112  to carry out the operations described herein using conventional programming techniques based on the flowcharts and descriptions provided herein. As a result, additional detail as to the specific program code has been omitted. The memory  302  also serves as data storage and to buffer packets of information received over the system backbone  104  for processing. As discussed more fully below, these information packets include page requests which are received on the system backbone  104  from another device. The processor  300  processes the packet and forwards a corresponding page request packet to the appropriate pager  114  via the system backbone  104 . 
     Moreover, the memory  302  functions to store an information look-up table as discussed below in relation to FIG.  10 . The look-up table is maintained by the processor  300  and includes information relating to the network address of the pagers  114  within the system. As discussed in relation to FIG. 13 below, the contents of the look-up table are updated in order that the information remains current as the pagers  114  roam about the region  116 . As is also discussed below, one or more of the mobile terminals  106  may also be designed to operate as a pager. In such case, the look-up table within the memory  302  also includes information as to the address of the mobile terminals  106  operating as pagers. 
     The pager server  112  also includes a voice synthesizer circuit  304  connected to the bus  294 . The voice synthesizer circuit  304  is controlled by the processor  300  to convert a previously digitized voice prompt into an analog audio signal which can be transmitted by the pager server  112  onto a telephone line to prompt a user to input desired information as discussed below. 
     The telephone interface  125  couples the pager server  112  to and serves as an interface between the pager server  112  and the local public telephone network. Such coupling may occur through a local PBX included at the location in which the LAN  102  is installed, or may be connected directly to a local telephone line as is well known. The telephone interface  125  includes conventional modem circuitry  350  for dialing an outgoing call, picking up an incoming call, dialing appropriate prefixes to access a local telephone line or a long distance carrier via a local telephone line, etc. Included as part of the modem circuitry  350  is a dual tone multiple frequency (DTMF) transmitter  352  and a DTMF receiver  354  as are conventionally known. The modem circuitry  350  including the DTMF transmitter  352  and receiver  354  is coupled to an input/output of the processor  300  of the pager server  112  via a bus  356 . Information is transferred bidirectionally between the local telephone line designated  358 , the pager server  112  and the telephone interface  125  using conventional modem techniques. Hence, further detail is omitted. 
     It is possible to access the pager server  112  via the local telephone network by dialing the number of the telephone line  358 . The telephone interface  125  will pick up the incoming call and serve as a means for transferring information received via the telephone line  358  to the processor  300  in the pager server  112 . Similarly, it is possible for the pager server  112  to dial out onto the local telephone line  358  via the telephone interface  125 . For example, the pager server  112  may dial a WAN-based paging service provider in order to communicate a page to a pager known to be outside the region  116  as discussed below. 
     The output of the voice synthesizer circuit  304  is coupled through the telephone interface  125  directly to the local telephone line  358  as represented in FIG.  6 . As a result, the output of the voice synthesizer circuit  304  can be used to communicate voice prompts directly over the telephone line  358 . 
     Although the telephone interface  125  is represented as interfacing the pager server  112  to one local telephone line  358 , it will be appreciated that the interface  125  can also be used to interface the pager server  112  to multiple local telephone lines if it is contemplated that many calls may need to be handled at the same time and that multiple lines are appropriate. 
     In operation, a page requester (e.g., a person or device wishing to initiate a page) can enter a page request into the system  100  using a variety of techniques in order to send a page to one of the pagers  114 . For instance, the page requester may telephone the pager server  112  via the telephone line  358  and telephone interface  125 . The page requester will then be prompted to enter information such as an identification (ID) number of the particular pager  114  to which a page is to be sent and the information which is to be included in the page. The pager server  112  will in turn generate a page request information packet including the page information and forward the packet to the pager  114  via the base station  108  with which the pager  114  is registered. Alternatively, some automated device such as a personal computer (not shown) may be programmed to telephone the pager server  112  via the telephone interface  125  and automatically transmit via the telephone line  358  pager ID information and page information. Such information may be in the form of an E-mail message generated by the personal computer. 
     Alternatively, a device associated with the LAN  102  can initiate a page request by transmitting a page request having the pager ID and number and page information to the pager server  112  which in turn prepares a formal page request packet which it routes to the appropriate pager  114 . Such devices for initiating a request can include one or more of the mobile terminals  106 , one or more work terminals  132  connected to the system backbone  104 , the host computer  130 , etc. These devices can be programmed to prompt a person wishing to send a page to enter the ID number of the pager  114  they wish to page and the message or other page information they wish to send. Upon receiving such information, the devices are programmed to create an information packet containing such information and transmit the packet to the pager server  112  via the system backbone  104 . As is discussed in more detail below, the information packet is configured such that the pager server  112  would recognize the information packet as a page request and direct the page request in the appropriate manner. 
     It is noted that although the pagers  114  are referred to by a pager ID “number”, such “number” need not literally be a number but merely some type of identification code which distinguishes one pager  114  from another pager  114 . 
     In order to integrate paging capabilities onto an existing LAN  102  most efficiently, it is preferred that the pager system  110  maintain the packet format of the existing LAN  102  to the extent possible. Thus, no new control fields are inserted into the packet format in the preferred embodiment. For example, FIG. 2 discussed above may represent the packet format of an existing LAN  102  to which the pager system  110  is added. As is explained in more detail below, rather than insert new control fields the page request information packets are recognized by the respective devices on the system backbone  104  by viewing either the source address field  156  or destination address field  158  in the existing packet format. If a page request is made via the telephone line  358  and interface  125 , the pager server  112  creates a page request packet which is placed onto the system backbone  104  wherein the source address field  156  would have the address of the pager server  112 . The destination address field  158  is the address (e.g., pager ID number) of the particular pager  114  intended to receive the page. If, on the other hand, the page request is made via a device on the LAN  102  (e.g., a work terminal  132 , mobile terminal  106 , etc.), initially the device transmits the packet with a destination address  158  of the pager server  112 . Upon receiving this packet, the pager server  112  converts the packet into a page request packet identical to the format of the packet produced by the pager server  112  when a request is received via the telephone interface  125 . Thus, all page request packets would have as their source address the address of the pager server  112 . In another embodiment, it would be possible to set the packet type via a control field in order to allow a mobile terminal  106  to distinguish between conventional messages and page messages. 
     In the preferred embodiment, each device in the system  100  (e.g., the mobile terminals  106 , base stations  108 , pagers  114 , work terminals  132 , etc.) is configured to review the source address field  156  of every packet which is received. If the source address corresponds to the pager server  112 , the packet is treated as a page request packet and all data in the data field  160  corresponds to the page message. If the address in the source address field  156  corresponds to any other address, the devices are configured to handle the packet in the conventional manner. Hence, for example, if a mobile terminal  106  is programmed to serve also as a pager, it can receive packets with the pager server  112  as the source address and can be programmed to convert the message included in the data field  160  into an alpha-numeric display which is then displayed on the display  174  (FIG.  3 ). If the mobile terminal  106  detects that the source address field  156  includes an address other than that of the pager server  112 , the packet is processed in the conventional manner for the particular communication system  100 . Since the packet format according to the present invention need not be changed from that of an existing LAN  102 , the remaining devices on the system backbone  104  handle the packets the same as any other and do not need to be specially reconfigured with respect to packet format to be compatible with the paging capability. 
     The operation of the pager system  110  of the present invention will now be described by way of illustrative examples. FIG. 7 represents the programmed operation of the pager server  112  with respect to a page request received from a “human” page requester via the telephone interface  125 . In step  400 , the processor  300  of the pager server  112  determines if a call has been received on the telephone line  358  via the telephone interface  125 . Specifically, when a call is received the telephone interface  125  picks up or answers the call and alerts the processor  300  of the incoming call via the bus  356  as shown in FIG.  6 . If no call has been received in step  400 , the processor  300  continues to loop around step  400 . 
     Upon receiving a call in step  400 , the pager server  112  proceeds to step  402  in which the call is responded to by the pager server  112 . Specifically, in step  402  the pager server  112  prompts the caller with a voice message to “ENTER PAGER ID NUMBER”. Such voice message is digitally stored in the memory  302  and the processor  300  causes the message to be provided to the voice synthesizer circuit  304  where it is converted into an analog audio signal and transmitted onto the telephone line  358 . The page requester at the other end of the telephone line  358  then enters the pager ID number of the pager  114  which the page requester wishes to page by inputting a sequence of DTMF tones from a telephone keypad (not shown). These DTMF tones are received by the DTMF receiver  354  of the telephone interface  125  and are converted into corresponding digital information representing the pager ID number using known techniques. Such digital information is then provided by the DTMF receiver  354  to the processor  300 . In step  404 , the processor  300  receives the pager ID number from the DTMF receiver  354 . 
     The processor  300  then compares the ID number with the pager ID numbers included in a pager server look-up table  405  stored in the memory  302  as mentioned above. As represented in FIG. 10, the pager server lookup table  405  contains a list of all the valid pager ID numbers in the system  110 , together with their corresponding network address in a format recognizable on the LAN  102 . For example, a pager ID number of “11 . . . 11” which may be input by a page requester in step  404  needs to be converted into an address which is recognizable by the various devices on the system backbone  104 , hereinafter referred to as the pager address or pager identification number or address. Note, however, that for mobile terminals  106  also serving as a pager, it will be the case that the pager identification number is the same as the mobile terminal address, and two separate addresses need not be assigned to the same device. In addition, since the present embodiment is based on a LAN  102  which utilizes source routing, the look-up table  405  is maintained by the processor  300  so as to include the corresponding base stations  108  with which the pagers  114  are presently registered. Such information relating to the corresponding base stations  108  includes source routing information for transmitting packets to the base stations  108 . Hence, when the pager server  112  transmits a page request packet to a pager  114 , the pager server  112  inserts the source routing information for the corresponding base station  108  in the source routing field. In the event the LAN  102  did not utilize source routing, the look-up table  405  need only include the list of valid pager ID numbers and their corresponding addresses recognizable on the LAN  102 . 
     The look-up table  405  also includes the pager ID numbers of pagers  114  which are known to be accessible only via an outside paging service provider (e.g., a conventional WAN based paging service provider). In such case, the look-up table  405  includes both the pager ID number and a flag set to indicate that the particular pager is serviced by a WAN based paging service provider. In the event a page request is received by the pager server  112  which is directed to such a pager, the pager server  112  contacts the WAN based paging service provider via the telephone interface  125  as described below. Furthermore, with respect to any mobile terminals  106  which are intended to receive page messages also, such mobile terminals  106  are also included in the look up table  405  together with their network address and base station information similar to the pagers  114 . 
     Continuing to refer to step  404  in FIG. 7, the processor  300  determines if in fact the pager ID number entered by the page requester (which could also represent a mobile terminal  106  acting as a pager) is included in the look-up table  405  so as to be considered valid. If the pager ID number is not in the look-up table, the processor  300  proceeds to step  406  in which it controls the voice synthesizer circuit  304  to communicate a voice message on the telephone line  358  indicating that an error has occurred and please retry entering the pager ID number. The processor  300  then returns to step  402  and the page requester is again prompted to enter the pager ID number. If such error in step  406  occurs a predetermined number of times in a row, the processor  300  may be programmed to terminate the telephone connection and return to step  400  (not shown in diagram). If the pager ID number entered in step  404  does match an ID number included in the look-up table  405  so as to represent a valid pager ID number, the processor  300  proceeds to step  408  in which the ID number is stored temporarily in the memory  302 . 
     Following step  408 , the processor  300  proceeds to step  410  in which the voice synthesizer circuit  304  is used by the processor  300  to transmit a voice prompt on the telephone line  358  to “ENTER PAGE MESSAGES”. The pager requester then enters another series of DTMF tones which are received by the DTMF receiver  354  and are converted to digital information that is provided to the processor  300  via the bus  356 . The DTMF tones can be encoded and decoded using known techniques to represent alphanumeric information or simply numeric information, for example. Hence, the message may be a telephone number to call or an alphanumeric message such as business information needed by the user. The processor  300  then checks in step  412  whether a message has been received from the page requester via the telephone interface  125 . For instance, it may be determined that a message has been received if the processor  300  recognizes that at least one alphanumeric character was entered and a calling party has hung up. If yes, the message is stored temporarily in the memory  302  in step  414 . If no, the processor  300  proceeds to step  416  where it determines if a predetermined amount of time has elapsed since the page requester was prompted to enter a message in step  410 . If no, the processor  300  returns to step  412 . If yes, the processor  300  proceeds to step  418  in which it utilizes the voice synthesizer circuit  304  to communicate a voice message on telephone line  358  that time for entering a message has run out. The processor  300  then instructs the telephone interface  125  to terminate the connection and the pager server  112  returns to step  400 . 
     After the page message has been received and stored in step  414 , the processor  300  proceeds to step  420 . In step  420  the processor  300  checks whether a flag in the look-up table  405  corresponding to the pager ID number stored in step  408  indicates that the pager is serviced by a WAN based paging service provider. If no, the particular pager  114  (or mobile terminal  106  acting as a pager is known to be) serviced within the system  110  then the processor  300  proceeds to step  422  in which a page request packet is generated as briefly described above. If, for example, the page request is directed to a pager  114  registered to a corresponding base station  108 , the processor  300  will generate a page request packet  150  as shown in FIG.  8 . The source address field  156  will include the address of the pager server  112 . The destination address field  158  will include the network address of the of the particular pager  114  identified by the pager ID number stored in step  408 . The network address is obtained based on the contents of the look-up table  405 . The source routing field  159  will include the source routing information corresponding to the base station  108  to which the pager  114  is currently registered, such information also being determined from the look-up table  405 . The data field  160  will include the message which was stored in step  414 . 
     In the event the pager ID number stored in step  408  is actually a mobile terminal  106  which is also operating as a pager, the source address field  156  again will include the address of the pager server  112 . The destination address field  158  will have the address of the mobile terminal  106 , and the source routing field  159  will have source routing information corresponding to the base station  108  with which the mobile terminal  106  is currently registered. Again, the destination address and source routing information are obtained from the look-up table  405 . 
     Following the formation of the page request packet in step  422 , the processor  300  proceeds to step  424  in which the processor  300  causes the page request packet generated in step  422  to be transmitted onto the system backbone  104  via the transceiver  290 . Ultimately, the base station  108  to which the pager  114  identified in the destination address field  158  of the page request packet is registered will receive the packet from the system backbone  104  and transmit the packet to the pager  114  via the RF transceiver as discussed below in connection with FIG.  11 . Following step  424 , the processor  300  returns to step  400 . 
     If in step  420  it is determined that the pager ID number corresponds to a pager which is known to be serviced only by the WAN based paging service provider, the processor  300  proceeds to step  428  as shown. In step  428 , the processor  300  causes the telephone interface  125  to dial a preprogrammed local access number of the WAN based paging service provider. Thereafter, the pager ID number and message stored in steps  408  and  414 , respectively, are communicated to the provider via the telephone interface  125 . Communications occur via DTMF tones generated by the DTMF transmitter  352  in response to instructions received from the processor  300 . The appropriate automated dialing procedures and communication of the pager ID number and the message are performed according to conventional techniques and a predetermined protocol. The WAN based paging service provider will then handle delivering the message to the appropriate pager as is conventional. Following step  428 , the processor  300  returns to step  400 . 
     FIG. 9 represents the operation of the pager server  112  in the case where another device on the system backbone  104  issues a page request. In this case, the devices (e.g., work terminals  132 , mobile terminals  106 , host computer  130 , etc.) capable of initiating a page request are configured to generate an information packet  150  for initiating such page request which includes in its destination address field  158  the address of the pager server  112 . The first ten bits (or other predetermined number) of the data field  160  include the pager ID number of the pager  114  to which the page request is to be sent. The remainder of the data field  160  is used to include the message which is to be sent to the pager  114 . Such message can be an alpha-numeric message alerting the pager user to call home, call the office, etc. The mobile terminals  106 , work terminals  132 , etc., which are intended to be able to initiate page requests have their respective processors programmed to prompt a user to enter the pager ID number and message information so as to be able to generate the packet. The thus created packets for initiating a page request are then sent to the pager server  112  to be converted to a formal page request packet and sent to the appropriate pager. Page requests initiated by mobile terminals  106  are communicated to the system backbone  104  and the pager server  112  via the base station  108  with which the mobile terminal  106  is registered according to conventional cellular communication techniques. Page requests initiated from work terminals  132  or other devices connected directly to the system backbone  104  are simply transmitted to the pager server  112  directly via the system backbone  104  according to the conventional LAN  102  protocol. 
     Beginning in step  500  of FIG. 9, the processor  300  of the page server  112  determines if a packet for initiating a page request has been received over the system backbone  104  via the transceiver  290 . As mentioned above, the page requests from devices on the system backbone  104  will include the address of the pager server  112  in the destination address field  158  and are henceforth received and recognized by the pager server  112 . Until such time as a packet for initiating a page request is received, the processor  300  continues to loop around step  500  as shown. Upon such a packet being received, the processor  300  proceeds to step  502  in which it extracts the first ten data bits from the data field  160 , such bits representing the pager ID number as mentioned above. Next, in step  504  the processor  300  determines if the pager ID number represented by the ten data bits represents a valid pager ID number based on the look-up table  405 . Such determination is made in the same manner discussed above in relation to step  404  (FIG.  7 ). If no, the processor  300  proceeds to step  506  in which the processor  300  generates an error message which is included in a return packet transmitted back to the device requesting that the page be initiated. The address of the device requesting the page is known based on the source address of the packet received in step  500 . The error message is included the data field  160  and is configured to notify the requesting device that an invalid pager ID number was received. Following step  506 , the processor  300  returns to step  500 . 
     If in step  504  it is determined that a valid pager ID number has been received, the processor  300  proceeds to step  508  in which the processor  300  extracts the page message from the remaining bits in the data field  160 . Following step  508 , the processor  300  proceeds to step  510  which is identical to step  420  described above with respect to FIG.  7 . Briefly, the processor  300  determines if the pager ID number corresponds to a pager  114  which is serviced by a WAN based paging service provider or alternatively is serviced within the region  116  by the pager server  112 . If the pager ID number represents a pager serviced by a WAN based paging service provider, the processor  300  proceeds to step  512  which is substantially identical to step  428  in FIG. 7, and a page request is transmitted to the WAN based paging service provider via the telephone interface  125 . Thereafter, the processor  300  returns to step  500 . It is noted that in step  512 , however, the message information and pager ID number are those obtained in steps  502  and  508 , respectively. 
     If in step  510  it is determined that the pager  114  identified by the pager ID number obtained in step  502  is not serviced by the WAN based paging service provider, and instead is serviced by the pager server  112 , the processor  300  proceeds to steps  514  and  516  in sequence. Steps  514  and  516  are substantially identical to steps  422  and  424  of FIG. 7, respectively. It is noted that in step  514 , however, the message information and pager ID number are those obtained in steps  502  and  508 , respectively. Otherwise, the operation of generating a page request packet for transmission to the respective pager  114  (or mobile terminal  106  acting as a pager) is identical. Following step  516 , the processor  300  returns to step  500 . 
     Accordingly, whether a page request is initiated from outside the LAN  102  (e.g., via the telephone line  358 ) or a device within the LAN  102 , the page server  112  receives the request and generates a page request packet which can be forwarded to a pager  114  or mobile terminal  106  acting as a pager. 
     Referring now to FIG. 11, a flowchart is shown for describing the programmed operation of a given base station  108  for transmitting a page request packet to the appropriate pager  114 . In step  550  the processor  256  determines whether any packets  150  have been received from the system backbone  104  via the transceiver  252 . If no, the processor  256  continues to loop around step  550 . If yes, the processor  256  proceeds to step  552  in which it extracts the destination address from the received packet. As indicated above, the pager server  112  includes in each page request packet the address of the particular pager  114  (or mobile terminal  106  acting as a pager) in the destination address field  158 . Thus, following step  552  the processor  256  proceeds to step  554  in which it determines whether the destination address field  158  identifies a pager  114  (or mobile terminal  106  acting as a pager) which is currently registered to the base station  108 . As briefly mentioned above, each base station  108  includes a memory  258  (FIG. 4) which includes a look-up table (denoted  556 ) which is maintained by the processor  256  so as to indicate the currently registered pagers  114  and mobile terminals  106 . 
     If the address in the destination address field  158  corresponds to one of the pagers  114  currently registered to the base station  108  as identified in the look-up table  556 , the processor  256  proceeds to step  558 . It is in step  558  that the base station  108  transmits the information contained in the page request packet (e.g., the page message) to the pager  114  itself. This is done using convention cellular communication techniques whereby the page request packet is forwarded to the pager  114  via the RF transmitter  264 . Specifically, the processor  256  performs any desired preprocessing of the page request packet received via the system backbone  104  and forwards the packet to the RF transmitter  264  which performs any encoding, modulation, etc., prior to transmitting the packet via the antenna  120 . Referring briefly to FIG. 4A, the pager  114  which is registered to the base station  108  will receive the packet via the antenna  218  and RF receiver  216 . The pager processor  195  evaluates the address in the destination address field  158  and if it matches the address of the pager  114 , the processor  195  concludes that the page request is intended for that particular pager  114 . The processor  195  extracts the page message from the data field  160  and stores it in memory  197 . The processor  195  also activates either the speaker  205  or vibrator  207  as described above to notify the user of the receipt of a page. The user can then recall the page message from the memory  197  using the view button  209  as discussed above. 
     As noted above, it is possible that the packet received in step  550  is directed to a mobile terminal  106  which also acts as a pager. The fact that the packet is destined for a mobile terminal  106  acting in the capacity of a pager can be easily ascertained by the base station  108  based on the source address information in the source address field  156 . Specifically, if the source address field includes the address of the pager server  112 , the base station  108  will know that the mobile terminal  106  in such case is acting as a pager. This need not necessarily impact the manner in which the packet is then forwarded by the base station to the mobile terminal  106 . However, to the extent it may be desirable for the base station to handle communications to the mobile terminal  106  differently depending on whether the packet is intended for paging or conventional purposes, such information from the source address field is useful. 
     Referring back to FIG. 11, following step  558  the processor  256  returns to step  550  as shown. If in step  554  it is determined that the destination address of the received packet does not correspond to a pager  114  or mobile terminal  106  acting as a pager, the processor  256  proceeds to step  560 . In step  560  the processor  256  processes the received packet as it would under conventional circumstances, such processing being conventional. Thereafter, the processor  256  returns to step  550 . 
     As discussed above, the mobile terminals  106  and pagers  114  are intended to be able to roam about the region  116  from cell to cell. Hence, a registration and deregistration process is carried out. Referring now to FIG. 12, the registration and deregistration process for the mobile terminals  106  and pagers  114  will be explained. It will be appreciated that in this case the process is identical for both mobile terminals  106  and pagers  114 . However it is certainly within the scope of the invention to use other and different procedures. With respect to each mobile terminal  106  and pager  114 , beginning in step  600  the processor  170 / 195  of the mobile terminal/pager begins executing a registration routine. Such routine is initiated when the mobile terminal/pager is first powered up, for example. In step  602 , the processor  170 / 195  broadcasts a “find router” packet via the RF transmitter  186 / 214  to any base stations  108  available to receive the broadcast. The “find router” packet includes information indicating to any base stations  108  which are within receiving range of the broadcast that the particular mobile terminal/pager is seeking to register with a base station. The base stations  108  which receive the packet, in turn, are preprogrammed to transmit a “router identification” packet via the RF transmitter  264  to any mobile terminals/pagers from which they receive a “find router” packet. These “router identification” packets include information as to the identity of the base station  108 , the amount of use (or “load”) on the base station, and an indication of the relative location of the base station in the LAN  102 . 
     In step  604 , the processor  170 / 195  within the mobile terminal/pager determines whether any “router identification” packets have been received from any base stations  108 , via the RF receiver  182 / 216 , within a predetermined period of time. If not, the processor  170 / 195  returns to step  602  and again transmits a “find router” packet. If the processor  170 / 195  determines that it did receive one or more “router identification” packets in step  604 , the processor  170 / 195  proceeds to step  606  in which it stores in the memory  176 / 197  all of the “router identification” packets received during the predetermined time. Next, in step  608 , the processor  170 / 195  is programmed to evaluate the packets according to a predetermined criteria in order to select a base station  108  with which to register. Such predetermined criteria may be based on, for example, which base station  108  exhibits the smallest load. Alternatively, the processor  170 / 195  may select the base station which is located in a particular relative location in the LAN  102 . In another embodiment, the processor  170 / 195  may select a base station  108  based on a combination of the criteria or based on some other criteria. The particular manner in which the mobile terminal/pager selects a base station  108  with which to register is not critical to the invention as will be appreciated. 
     In step  610 , the processor  170 / 195  transmits a registration request packet directly to the selected base station  108  via the RF transmitter  186 / 214 . In step  612 , the processor  170 / 195  determines whether an acknowledgment packet is received via the RF receiver  182 / 216  from the selected base station  108 . Each base station  108  is programmed to transmit a registration request acknowledgment packet to a requesting mobile terminal/pager in the event the mobile terminal/pager is registered. If, in step  612 , the processor  170 / 195  determines that the registration request was not acknowledged, the processor  170 / 195  returns to step  608  and selects another possible base station  108  with which to attempt to register. If there are no other base stations  108  from which a “router identification” has be received, the processor  170 / 195  is programmed to return to step  602  (not shown). In the event the processor  170 / 195  does receive a registration request acknowledgment in step  612 , the processor  170 / 195  proceeds to step  614  whereby the mobile terminal/pager now considers itself registered with the selected base station  108 . 
     As the mobile terminallpager remains registered to a particular base station  108 , the mobile terminal/pager will continue to receive transmissions from the base station  108  indicating that the mobile terminal/pager is still within range of the base station. Such transmissions may be in the form of acknowledgments of the receipt of information packets from the mobile terminal/pager. In the event the mobile terminallpager has been idle and has not transmitted information to the base station  108  for over a predetermined period of time or vice versa, the processor  170 / 195  is preferably programmed to send out an inquiry requesting that the base station  108  transmit an acknowledgment informing the mobile terminal/pager that it is still within range of the base station  108 . As will be expected, the mobile terminal/pager may change location and eventually fall out of range of the base station  108 . Alternatively, transmission conditions may change (due to obstructions or the like) such that the mobile terminal/pager is no longer within range of the base station  108 . 
     Therefore, in step  616  the processor  170 / 195  is programmed to determine whether packets from the mobile terminal/pager are still being acknowledged by the base station  108  with which it is registered. If yes, the processor  170 / 195  returns to step  614  as shown and the mobile terminal pager remains registered. If no, the processor  170 / 195  proceeds to step  618  in which it is considered that the mobile terminal/pager is out of range and no longer validly registered with the base station  108 . Consequently, the processor  170 / 195  returns to the beginning of the registration routine and step  602  as shown. Thereafter, the mobile terminal/pager repeats the above-described procedure in an effort to re-register with another base station  108 . 
     As mentioned above, the base stations  108  are programmed to transmit a registration request acknowledgment packet to a requesting mobile terminal/pager in the event the mobile terminal/pager is registered. At the same time, the base stations  108  are programmed to update the contents of their respective look-up tables  556  to reflect the new registrations. In addition, the base stations  108  are programmed to broadcast a new registration packet onto the system backbone  104  indicating to the other devices on the system backbone  104  that a mobile terminal/pager has become newly registered therewith and specifically identifying the particular mobile terminal/pager. This broadcast packet is received by each of the other base stations  108  as well as the pager server  112 . This information is used by those devices to update their respective look-up tables  556  and  405 . For example, the base station  108  with which the mobile terminal/pager was previously registered would receive the broadcast packet and recognize that the mobile terminal/pager is no longer registered to it. Hence, the base station  108  is programmed to clear the entry from the look-up table  556 . In the case of a LAN  102  in which source routing is used, such information relating to where the mobile terminals/pagers are now registered is used to change any source routing information within the base station  108  to the extent appropriate. 
     FIG. 13 shows the manner in which the pager server  112  receives and processes the new registration packets sent by the base stations  108 . Specifically, in step  700  the pager server  112  waits to receive a new registration packet which is broadcast onto the system backbone  104 . The pager server  112  continues to loop through step  700  until such packet is received. Upon receiving a packet indicating that a pager  114  or a mobile terminal  106  acting as a pager has newly registered with a base station, the pager server  112  updates the information in its look-up table  405  as represented in step  702 . Specifically, the new base station  108  with which the pager  114  or base station  106  is now registered is used to update the previous entry in the look-up table  405 . If previously there was not an entry for the particular pager  114  in the look-up table  405 , such an entry is created by the pager server  112 . Thereafter, the pager server  112  returns to step  700 . 
     Additional detail regarding a registration protocol and possible techniques for updating the look-up tables in accordance with the invention can be found in co-pending U.S. App. Ser. No. 08/539,130 entitled “Network Communication System with Information Rerouting Capabilities”. The entire disclosure of application Ser. No. 08/539,130 is incorporated herein by reference. However, it will be appreciated that conventional techniques can also be used. 
     In another embodiment, each of the mobile terminals  106  and pagers  116  operate in a power savings mode whereby the devices typically reside in a low power sleep mode. Rather than the base stations  108  immediately transmitting packets to the mobile terminals  106  or pagers  114  upon receipt, the packets are stored by the based stations  108 . The mobile terminals  106  and pagers  114  are configured to periodically power-up from the sleep mode and poll their corresponding base stations  108  for messages at which time the base station  108  transmits the stored packets to the mobile terminals  106  and pagers  114 . An exemplary protocol is described in U.S. Pat. No. 5,276,680. However, such power saving feature is not necessary to the invention as will be appreciated. 
     In an alternative embodiment, the page message provided by the page requester may be in the form of a voice message which is digitized and included in the data field of the page request packet. It may be the case that a voice transfer program is used to transfer voice messages via the paging system. This may be accomplished by using conventionally known voice encoding and decoding programs to provide half-duplex voice transfer over the system backbone  104 . For example, a pager  114  or mobile terminal  106  functioning as a pager may be loaded with a data-to-voice program. Then, if a page message is received with a voice message, the data-to-voice conversion program converts the message into translatable sounds and amplifies and communicates the signal via the speaker  205 , for example. Similarly, a page requester may utilize a voice-to-data program and create a short digitized voice message, typically on the order of five seconds, which is converted into standard packet format and wirelessly communicated to the pager server  112  via the LAN  102  as an initial page request. Such voice-to-data conversion can be carried out, for example, by the telephone interface  125  which has circuitry therein to convert the analog voice signal on the telephone line to a digitized signal. The pager server  112  can be programmed to prompt the page requester to enter a voice message by beginning to speak after a beep, for example. In addition, or alternatively, the mobile terminals  106  and/or other devices  132  on the system backbone  104  may include a microphone (not shown) for obtaining an analog voice signal and programmed circuitry (also not shown) for converting the voice signal to a digitized signal which is then included in the data field of the packet initially requesting a page. Voice conversion programs commercially available on the market today and suitable for use in such an embodiment include CELP and Vocoder. 
     As will be appreciated, the present invention makes it possible to provide paging capabilities over existing or new local area networks. Monthly service charges associated with conventional paging systems are no longer necessary. 
     Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications, and is limited only by the scope of the following claims.