WIRELESS COMMUNICATION DEVICE WITH REPLACEABLE BATTERY AND PREPAID CALLING TIME

Abstract: A wireless communication device (10) is provided which is capable of interfacing with a base station of a service provider and intended for occasional use without requiring a subscription with the service provider. The device (10) comprises a non-rechargeable replaceable power source (17) with a memory (18) comprising information code for uniquely identifying the power source (17) and a prepaid calling time period. After the prepaid calling time period of the wireless communication device is exhausted, the power source is replaced with a new power source having a new prepaid calling time period.

Description: Wireless Communication Device with Replaceable Battery and Prepaid Calling Time BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to wireless communication devices and, in particular, to such a device capable of interfacing with a base station of a service provider and intended for occasional use without requiring a subscription with the service provider. 2. Description of related art Conventional wireless communication devices are generally supported by a service provider selected by the device user who may enter into a contractual relationship with the service provider. Cancellation of the service agreement prior to the time period agreed to may result in substantial monetary penalties. Moreover, the subscriber may be assigned a telephone number having the same area code as the wireline telephone service provided to the subscriber's residence or business. This telephone number and other ID codes associated with the wireless communication device allow the subscriber to initiate and to receive telephone calls from any subscriber connected to the public switched telephone network (PSTN). Although a large number of subscribers to the wireless phone service will use their devices for both initiating and receiving calls, and will therefore require a conventional telephone number, there are other subscribers and many potential subscribers who may want to use their wireless communication device only occasionally or for emergencies and do not need the capability of receiving incoming calls. Such subscribers may prefer to make a one-time purchase of a wireless communication device at a reasonable cost and may subsequently want to purchase a certain amount of prepaid calling time, for example in the form of a certain number of time units, for just such occasional use. In addition, wireless communication devices almost exclusively use rechargeable batteries to provide power to the device. Rechargeable batteries are known to provide the relatively large current required for transmitting signals, but have the drawback that the charge may not be retained over extended periods of time. In a wireless communication device intended for occasional use, it could therefore be anticipated that the subscriber may not be diligent in maintaining the rechargeable battery in its charged state, thereby preventing the wireless phone from operating properly when needed. Emergency wireless phones and wireless phones with a limited calling time are known in the art. WO 96/03001, for example, shows a wireless phone wherein removal of a sealing means allows the phone to be switched on and the simultaneous transmission of an ID code to the telephone exchange enables access to a predetermined telephone line for a restricted period of time. The user does not need a subscription contract. U.S. Patent 5,138,650 shows a wireless phone having memory means for storing a credit balance prior to usage of the phone and means for updating the credit balance. The phone can be used as long as there remains a credit balance. GB A 2 262 685 describes a wireless phone device where radio transmission from the device can be terminated either by receiving a remote termination signal or after a predetermined length of time which is determined at the time of purchase of the device or its manufacture. The wireless communication devices described above are either intended to be disposable after expiration of the preprogrammed connect time which is rather expensive in view of the manufacturing cost of a wireless communication device, or the accounting data are managed and updated by the service provider. Therefore, there is a need for a wireless communication device for occasional use which can be purchased and operated reliably and inexpensively and which does not require a subscription contract to be in force with a service provider at all times. BRIEF DESCRIPTION OF THE DRAWINGS The structure and operation of the invention, together with other objects and advantages thereof, may best be understood by reading the detailed description to follow in connection with the drawings in which unique reference numerals have been used throughout for each part and wherein: Fig. 1 shows a wireless communication device comprising a power source, in accordance with the present invention, and incorporating identification and accounting means; Fig. 2 is an isometric view of the power source used in the device of Fig. 1 ; Fig. 3 shows a schematic block diagram of the wireless communication device of Fig. 1; and Fig. 4 is a flow diagram depicting the sequence of calling steps utilized in the operation of the device of Fig. 1. DESCRIPTION OF THE PREFERRED EMBODIMENTS There is shown in Fig. 1 a wireless communication device 10 comprising a housing 8 to which an antenna 45 is attached for receiving and transmitting radio signals to a base station (not shown). As best seen in the block diagram of Fig. 3, wireless communication device 10 further comprises a conventional RF transceiver 50, an audio section 53, an ear phone 55, and a microphone 54, connected as shown. RF transceiver 50 is further connected to a controller 52 which handles input/output functions, such as interfacing with a keypad 62 and a display 70. RF transceiver 50 may also interface directly with audio section 53, for example, so that status information about the wireless communication device 10 may be made via ear phone 55. In a conventional wireless communication device, the identification code of the device and/or the telephone number assigned to the device as well as other relevant registration data are typically stored in an EEPROM embedded in or associated with the a controller. The conventional wireless communication device is ready to operate after power is applied by, for example, a rechargeable battery. In wireless communication device 10, controller 52 does not store all of the necessary information for establishing an information communication channel. Therefore, when power is supplied to wireless communication device 10, the user is not provided with connection to a network of a service provider. As explained in greater detail below, wireless communication device 10 comprises an integrated power source 12 comprising a battery 17 and storage means 18, which may be a semiconductor chip or another read- and write-enabled memory device. Storage means 18 contains a unique information code allowing the user to initiate a radio telephone call of limited duration by inserting the power source 12 in the wireless communication device 10. As best seen in Fig. 2, battery 17 comprises terminals 14 and 16 from which power is provided to terminals 14a and 16a located on a connector 13 adapted to mate with a receptacle 25 of wireless communication device 10. Storage means 18 is preferably integrated with power source 12 and has I/O connections (not shown) connected to terminals 15ι, 15 2 , ..., 15„ on connector 13. Memory means 18 may also be capable of interrupting the flow of power, via a switching means 19 interposed between at least one of battery terminals 14 and 16 and a respective one of terminals 14a and 16a, as shown schematically in Fig. 2. Wireless communication device 10 is provided with a receptacle 25 for mating with connector 13 as a means of: i) providing electrical power from battery 17 to wireless communication device 10, and ii) conveying identification codes, including possible information with respect to the remaining prepaid calling time to be transmitted to the service provider. It should be understood that, although power source 12 is shown in Fig. 3 as being connected to controller 52, power source 12 can alternatively be connected to any other component in wireless communication device 10 capable of accepting power and processing the ID codes and other information. Integral power source 12 is preferably formed by joining battery 17, memory means 18, optional switching means 19, and connector 13 in a sealed tamperproof enclosure. Memory means 18 may comprise a read-only memory portion for storing the unique identification code of the battery and the amount of the initial prepaid calling time purchased by the user. Memory means 18 may further conprise a rewritable memory portion for tracking and/or updating the remaining calling time. The rewritable memory could either be tracked and/or updated in power source 12 itself through an internal clock without communicating information about the remaining calling time to the service provider. At the point of sale of power source 12, the user may be able to select a specific service provider which is then encoded within the ID code pre- written and stored in memory means 18, or the user may be able to select a service provider when the first call with a new power source 12' is initiated. The present invention has the advantage that the possibility for misuse or fraud is reduced, since the calling time has already been prepaid and the total accumulated calling time with a given power source 12 is limited to the prepaid calling time (substantially equal to the charge capacity of battery 17). The operation of wireless communication device 10 is best understood from the flow diagram of Fig. 4. In the following embodiment, it will be assumed that a specific service provider has been pre-selected. With power source 12 connected to device 10, the user initiates a call in step 102 by using keys of keypad 62 such as, for example a SEND key. In step 104, data stored in memory means 18 (e.g., the LD code of the power source 12 or information about the calling time balance) are communicated to the service provider. If these data are valid, the service provider sends a message to wireless communication device 10 enabling the initiated call to proceed. If these data are not valid, then the service provider will either not respond or will send a message that the call is not allowed. If the call cannot proceed, the user may be able to check the remaining calling time balance either via display 70 or the balance may be announced by audio signals via ear phone 55. In this situation, the calling time balance will most likely be zero and the user will have to insert a new power source 12" and initiate a new call in step 102. If the call is allowed to proceed in step 106, the remaining calling time balance may be communicated to the user in the manner described above and the call is set up in step 110. At step 112, the call can terminate in two ways. If the call is shorter than the remaining calling time balance, then the call is completed normally, the calling time balance is updated in step 120, either in a self-contained mode, by updating the balance in memory means 18 without communicating balance information to and/or receiving balance information from the service provider, or the calling time balance is updated at the end of the call by a signal from the service provider. If the duration of the call approached the remaining calling time balance, then the user will be notified in step 114, preferably by an audio message generated in wireless communication device 10, and advised to insert a new power source 12' with a sufficient calling time balance and to redial the call. Alternatively, a backup battery 51 could be incorporated wireless communication device 10 to permit changing power source 12 within a certain short time without losing the radio connection. As noted above, wireless communication device 10 does not require a standard telephone number since device 10 is not intended to receive incoming telephone calls. Consequently, the ID code is not restricted to a combination of ten digits, as is customary, for example, in the USA. According to the Common Air Interface (CAI) protocol, the ID number may contain up to 64 bits which could easily accommodate the projected number of single use power sources 12 of the invention, wherein each ID number is used only once. While there have been described what at present are considered to be the preferred embodiments of the present invention, it will be readily apparent to those skilled in the art that various changes may be made therein without departing from the spirit of the invention, and it is intended in the claims to cover such changes and modifications as fall within the true spirit and scope of the invention.

Claims: What is claimed is: 1. A wireless communication device (10) suitable for interfacing with a wireless telephone network of a service provider without requiring a subscription with the service provider, said wireless communication (10) device comprising: communication means (50) for transmitting information of intelligence to and receiving such information from the wireless telephone network; and, removable power means (12) electrically interfacing with said communication means (50), said power means (12) comprising: a battery (17); and, memory means (18) non-detachably secured to and integral with said power means (12) and comprising information code for uniquely identifying said power means (12) and a prepaid calling time period; wherein said wireless communication device (10) can interface with the wireless telephone network as long as the accumulated calling time is less than the prepaid calling time period, whereafter the wireless communication device (10) can be reused upon replacing said removable power means (12). 2. The wireless communication device of claim 1, wherein said information code is different from a valid telephone number of a public telephone network. 3. The wireless communication device of claim 1, wherein said battery (17) is not rechargeable. 4. The wireless communication device of claim 3, wherein said battery (17) is capable of providing power to said communication means (50) for a time period which is not significantly longer than the duration of the prepaid calling time period. 5. The wireless communication device of claim 1, wherein the service provider is selected when the power means is purchased. 6. The wireless communication device of claim 1, wherein said memory means (18) further comprises updating means for tracking and updating the accumulated calling time without requiring communication with the service provider. 7. The wireless communication device of claim 6, wherein said power means (12) further comprises switching means (19) electrically connected to said battery (17) and activated by said memory means (18) for disconnecting power to said communication means (50) when the accumulated calling time exceeds the prepaid calling time period. 8. The wireless communication device of claim 1 further comprising a backup battery (51) for supplying electrical power to said communication means (50) for allowing the wireless communication device to remain connected to the wireless telephone network for a certain period of time during which time the power source in the wireless communication device can be exchanged for a different power source having a new prepaid calling time period. 9. A method for allowing a user to initiate a radio telephone call from a wireless communication device capable of interfacing with a wireless telephone network of a service provider without requiring a subscription with the service provider, said wireless communication device adapted to operate by means of a removable power source, said method comprising the steps of: establishing a call connection to the wireless network and allowing said call connection to continue until the accumulated calling time exceeds the prepaid calling time period; alerting the user when the accumulated calling time exceeds the prepaid calling time period; and prompting the user to insert a new power source which include a new prepaid calling time period, in order to continue said connected call or to establish a new call connection.

Inventors: KEATING WILLIAM E, KEATING, WILLIAM, E.
Applicants: POLAROID CORP, POLAROID CORPORATION
Application year: 1998
Main classification: H04M17
IPC codes: H04M17, H04W88