GB2249920A

GB2249920A - Cellular telephone call detail recording system for billing

Info

Publication number: GB2249920A
Application number: GB9114049A
Authority: GB
Inventors: Masayuki Higuchi; Stephen T Hardin; Sadao Kotatsu; Akira Ikeda
Original assignee: Oki America Inc
Current assignee: Oki Semiconductor America Inc
Priority date: 1990-11-13
Filing date: 1991-06-28
Publication date: 1992-05-20
Also published as: GB9114049D0; JPH04268855A; DE4137348A1; CA2046736A1

Abstract

A cellular telephone call detail recording system records details such as number called, call duration and time of day for calculation of call billing. A processing computer located externally to the cellular telephone contains a database of call charges, and processes the call details to provide the billing data. A connector such as an RS232 interface is provided for connecting the cellular telephone to the call detail processing computer. The system may further include a protocol conversion unit for matching the protocol of the cellular telephone and the call detail processing arrangement. <IMAGE>

Description

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CELLULAR TELEPHON CAL DETAIL RECORDING SSTE .DTD:

The invention relates to a cellular telephone call detail recording system, and more particularly a call detail recording system arranged to be used in rental of cellular telephones and wherein the system provides a total blllng statement for each billing period.

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BACKGROUND AND PRIOR ART .DTD:

Cellular telephones for use in automobiles have become widely used In recent years. As a result of the continued devel- i0 opment of these devices they have become smaller and more effi- cient, and are now widely used in the form of a self-contained handheld unit, and the devices are no longer necessarily tied to an individual vehicle and its electrical installation. As a further result, a market has developed wherein a rental agency rents a cellular telephone to a renter to be used for a given period of time and the renter pays thm rental agency a given rental fee based on a given tariff which includes, among other things, the uratlon of the rental and the cost of the telephone calls made with the cellular phone. For the purpose of billing the renter, it is necessary that all details pertaining to the use of the cellular phone be recorded during the time it was in the possession of the renter. In order to keep the cellular telephone as small and compact as possible, it is very desirable that the cellular phone be equipped with the smallest possible memory sufficient to store all pertinent call details, so that a 5 complete billing statement can be prepared at the end of the billing period.

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The computation of the cost of each call,however, requires, in accordance with established tariffs, that each call be evaluated on the basis of at least the following details: the length of the call, the day and the time of the day the call is made, and for outgoing calls the distance between the calling station and the called station. The applicable tariff by necessity becomes very voluminous since the distance between all possible points of origin and points of destination must be available in tabular form before the computation can be made. It is therefore not practical to have the tariff tables built into a small compact cellular telephone. Other call details may also be required e.g. whether the call is an incoming or outgoing call.

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A further complicating factor relates to the fact that the searching of large data bases as required for call billing require certain highly developed protocols for data echare Such protoc61S are not practically applied to a small handheld device such'as a cellular telephone wherein the emphasis is on smallness and low crrent drain.

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A search of the prior art has not identified a satisfactory solution for the problems described hereinabove. Conventional telephones fixedly wied to a telephone exchange with a data base being part of the exchange apparatus has long been known, as for example shown in U.S. Patent No. 4,585,904, which shows a fied telephone with an interface'and modem for connection With a data base.

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Conventional telephones are normally not used in a rental arrangement, wherein a bill is to be paid upon return of the rented device, as is the case with the cellular phone in the instant invention.

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It is accordingly an object of the instant invention to provide a cellular telephone call detail recording system which includes a small handheld cellular telephone with a limited built-ln data base and interface capabilities for communicating with a large data base for billing purposes.

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SUMMARY OFTHE XNVENTION .DTD:

The invention relates to a system which will facilitate the billing routine for rental radiotelephone equipment. It will accomplish this by creating a paperless system with the exception oP the flal bill. To properly bill a user for service from a rented radiotelephone, parameters for each call, in the following called "call details", must be known by the rental agent, so that the agent may rent the radiotelephone unlt while restricting as few call types as possible. These dfferent call types would include long distance calls, calls made in a subscriber system different from the radiotelephone's home system, operator assisted calls, and credit card calls. A system includes three (3) main units: a cellular telephone, a PCU (Protocol Conversion Unit), and a computer terminal or a personal computer {PC).

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The cellular telephone portion of the system must be able to store detailed records of each call placed while the unit is being rented. To accomplish this requires the use of EEPROM technology to store the "Call Detail Records" or CDR for each I0 incoming and outgoing call. In order to bill the customer correctly for each individual call the rental agent must be able to obtain this information from the CDR memory of the phone. This is done using data transmission between the phone and the computer terminal or the PC. So that it may be possible for the 15 terminal and the phone to communicate with each other a PCU is ! used to translate the telephone output data into RS232 form. The PCU is also used to translate terminal side RS2B2 data into a format understandable for the telephone.

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There is in accordance with the instant invention provided a cellular telephone call detail recordlng system which includes a21prallty Of cellular telephones, a call detali memory built into he cellular telephone for storing call detalls a data base including call detail processing data located external to the cellular telephone, and a connecting arrangement with suitable interfaces for connecting the cellular telephone wlth ! the external call detail processing means.

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In accordance with a further feature there is provided a cellular telephone call detall recording system including protocol conversion arrangement as part of the connecting arrangement.

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In accordance with still another feature there is provided a cellular telephone call detail recording system wherein the call detail memory includes capability for storing at least one of (a) originating call data, (b) time and date of i0 originating the calls, and (c) call duration.

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The cellular telephone call detail recording system includes a cellular telephone having a first protocol for trans- mitting and receiving call data, a call processing arrangement which has a different protocol for transmitting and receiving data, and the connecting arrangement which includes a protocol conversion arrangement for reconciling and matching the first and the other different call protocol, and further a tariff memory included in the call processing arrangement. It further Includes a call cost computing arrangement which is communlCatlngly asso- ciated with the call tariff memory for computing the cost of calls accordlng to the call details-stored in the call detall memory of the cellular telephone.

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In accordance with the invention, there is further provided a cellular telephone adapted for connection to a call 25 detail processing system, wherein the ceJ.lular telephone I0 includes a call detail memory for storing call details, and a connecting arrangement for connecting the cellular telephone with, wherein the cellular telephone further includes a clock calendar for recording time and date of each call and a call restriction feature which restricts calls that can be made to certain estrlcted numbers.

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Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment which is illustrated schematically in the accompanying drawings.

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BRIEF DESCRIFTION O__FFTHE FIGURES Figure 1 is a block diagram of a cellular call detail recording system based on a personal comptlter; Figure 2 is a block diagram of a cellular call detail recording system based on an off-premlses main frame computer; Figure 3 is a perspective view of a cellular telephone; Figure 4 is a flow-chart showing the main steps of call processing transaction.

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Figure 5 is a block diagram of the cellular telephone; un it.

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J Figure 6 is a block dlagram of the protocol conversion Before explaining the disclosed embodiment of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown since the invention is capable oúother embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.

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oF 7J PREF]:R F In Figure I a cellular telephone I is of the type that is completely self-contalned with built-ln rechargeable power source, which can be used in any location where cellular telephone service is available.

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I0 In accordance with the instant invention, a rental agency has a stock of such phones that are available for customers to rent for a given rental period. After the phone Is returned o the rental agency, It is placed In an adapter Unlt 2, in whlch it is cradled while call detail records stored in an internal memory in the phone are transferred to a protocol conversion unit 12 vla a data cable 7, advantageously terminated in plugs 6 and 8 respectively at the adapter unlt and at the proto- col conversion unit.

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The plug 6 communicates with a matching Jack 5 in the adapter unlt 2, which is In turn connected vla an Internal connector 4 Im the adapter unit 2 connected wlth the cellular phone via a Jack 3 in the bottom end of the phone. Call deEall records stored in the cellular phone I are downloaded into the protocol conversion unit 12 using a data transmission protocol detetmlned 25 by a microprocessor e.g. the OKI type MSMaOLI54 in the cellular phone.

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After the call detail records have been downloaded to a buffer memory in the protocol conversion unit 12, it is reformat- ted according to a protocol suitable for communication with a call processing computer 19, such as the well-known protocol RS232 or any other suitable protocol.

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The personal computer 19 includes in conventional man- ner a monitor 22, a keyboard 23 and a central processing unit 24 with suitable memory devices such as floppy disk drlves and a I0 hard disk. A conventional printer 26 is connected via printer cable 27 to the central processing unit 24 for printing out billing statements for the rental of the cellular phone.

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The billing program including tariff tables are advantageously supplied on one or more floppy disks 28 that are loaded into the memory of the personal computer 19 via one of its disk drives 29.

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Figure 2 shows an arrangement wherein the call detail processing is performed in an external mainframe or gneal computer of adequate capacity to handle billing from several rental agencies. It has the same elements as shown with the same reference numbers as seen in Figure I, but has instead of'a a personal computer a printer and keyboard unit Bl, adapted to communicate via connection 32 with the protocol conversion unit 12, advantageously on RS232 protocol or any other suitable proto25 col for short distance data exchange.

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The printer and keyboard unit 31 may advantageously be a small personal computer of limited capacity or a dedicated printer keyboard unit 39,41 adapted to communicate via a telephone connection 33, either switched or dedicated. In this case com- munlcation is advantageously performed on the basis of the well- known ASCII format. A universal asynchronous receiver-transmit- ter (UART) 36 is provided which communicates via modems 37a,37b with a mainframe computer 38, which contains the billlng programs, tariffs and any other information required for processing I0 of the call detail records. The billing information is returned via the telephone connection 33, and Is printed out as a billing statement on the printer 39. The keyboard 41 serves as a general human interface.

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Figure 3 shows the cellular telephone I in greater detail. It is a handheld unit with an earplece 42, a microphone 44, a keypad 43 with the Usual telephone dlal keys 0,I-9, and #, and a number of special keys 46 for use in the cellular network. An LCD display 47 serves to Inform the user of call progress and status and other information as may be of value to the user. An antenna 48 serves both the transmit and receive side of the phone.

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The following is a brief description of the call handling with the disclosed system and details of the protocol between the phone and the protocol conversion unit. The RS232 protocol is a widely used industry standard for serial transmission. The ASCII protocol described in connection with Figure 2 is also a widely used protocol for long distance data communlcatlon.

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The cellular phone in the system according to the invention is Capable of placing and receiving telephone calls from any place within a cellular service system. Whenever a call iS in progress the telephone records into a call detail memory in the phone certain data, i.e. "details" of the call. The details include:

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a) Incoming or Outgoing Call - One bit in memory indicates whether the call was an incoming call or an oUtgoing call.

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b} Call Detail Record Address in memory - The number of a particular call starting with 000 is used when the phone has no Call Data Records in memory.

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c) Called Address - For an outgoing call this is the dialed phone number.

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d} System Identification (SID}- The SID of the sys- tem in which the phone was used to place the call.

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e) Air Time - The time of each call rounded up to the j nearest minute.

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There may further be provided as n optional feature a clock-calendar for time-of-day and date information.

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After all of the Call Data Record Address spaces are full, the unlt will keep two timers. One timer is for total i0 airtlme after the CDR is full and the other timer is only for calls which are made in a roam state where the phone is not being used in its home system.

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The protocol for transmit and receive data on the phone side of the system using the OKI Semiconductor MSM80CI54 Microprocessor may typically be as follows:

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From the phone to the protocol conversion unlt -Start Bit Length:

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-Data Length -stop Bit Length:

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-Signal Polarity:

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1 bit 16 bit I bit Negative Logic From the protocol conversion unit to the phone:

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-Start Bit Length:

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-Data Length -Stop Bit Length:

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-Slnal Polarity:

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1 bit II bit 1 bit Negative Logic Figure 4 is a flow chart showing the major metho(] steps in processing a call. After "Starc'' I00 a called humor is entered in step I01. In step 102 a determination is made whether the call counter is at Its allowed maximum. If affIzlmatlve, no more outgoing toll or billable calls are allowed. If the maxlmum number of calls has been reached the call restriction level is reset to disallow toll charges. The process continues in step 111, when the phone is returned to the rental agency.

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Before the phone s returned, any time accumulated on non-restrlcted calis made or received is recorded in two time accumulators, one for all call durations after the memory Is full and one for call durations made in a roam state, i.e. wherein the phone is not being used In its home system, as shown In steps 104 and 105. If the result of step 102 is negative, the call counter is incremented in step 106, and the called number is stored in the call detail memory of the phone in step 107. The called number is sent to the cellular network and a determination is I0 made in step 103 to see if the call is answered. If negative, the call may later be re-entered in step I00. If affirmative, the call timer is started in step 108 before answer supervision is received, as seen in the flow chart, Fig. 4. At the end of the call, the elapsed time is stored in step 109. After the end of the rental period, the phone is returned to the rental agency in step Iii, and the phone is inserted in the adapter unit 2 Used in the rental office as a convenient interface for the phone wlth the billing system. In the adapter unit the phone is connected via the connector 3 with the protocol conversion unit and the call detail data are transmitted to thee protocol conversion unit in step I121 uslng the phone's dsta protocol. In the protocol conversion unit 12, the call detail data are converted to a standard protocol such as, for example, RS-232 in step 113, and the call detail data are transmitted to the call process computer 25 in step I14. The call process computer determines for each call the proper call tariff stored in its memory, in step 116, and computes the charge for each call based on the call billing time, in step 117. In case the call process computer is remotely located, the call charges are returned to the local printer in step 118, as shown in Fig. 2, and printed out as a complete billing statement in step 119. In case the call process computer is colocated as in Fig. i, step 118 is skipped. After the billing statement is printed out, the call detail data in the phone are cleared in step 121, the phone is deactivated to disallow .DTD:

Cnvalld use and the display shows "locked" in step 122, the phone is returned to inventory in step 123, and the process is completed in step 124.

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The cellular phone according to the invention may advantageously have many of the calling features known froom 15. conventional cellular phones; a directory memory with frequently used called numbers, redlal feature for redlallng of busy or unanswered numbers, a number assignment module for each phone in the inventory of the rental agency, a user-programmable resale tariff in the call processing computer, call restriction means for restricting calling of certain classes of numbers, e.g.

numbers in foreign countries Fre 5 shows in block diagram form the structure of a cellular phone according to the invention, wherein the apparatus in the dashed block 51 represents the structure of a conventional 25 cellular phone, which includes a radio transmitter 52 and radio receiver 53 both connected to an antenna 48. A microphone 44 and an earpiece 42 are respectively connected to the transmitter and receiver. A control unit 54 includes a microprocessor with an internal bus 57 connected to a memory 58 with control programs for controlling the operation of the telephone. An Interface 59 also connected to the bus 57 provides interfacing to a keypad 43,46, a display 47, a protocol bus 61 connected to the I/O connector 3 of the phone, a bus 62 controlling the assignment module 64 which contains an EEPROM for storing a number assigned 10 uniquely to the telephone in the rental agency's inventory of cellular phones. A call counter 63 is connected via a bus 64 to the interface 59, and seves to count the number of allowed calls for the telephone before it is returned to the rental agency. A call timer 66 serves to time the duration, i.e. elapsed time, of each call, which is entered into a call detail data memory 67 together with other detail data for calls made as described above.

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When the call counter is full the phone reacts by resetting the call restriction level and keeping 8 rimer for total alrtlme after this point and keeping a timer for roaming airtlme after this point.

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Figure @ shows circuit details of the protocol conversion unit 12, which is connected to the cellular phone adapter unit 2 via datm cable 14 as described above. The call 25 detail data are entered into an incoming memory 71 under control i0 of a memory control circuit 72 with a control device which can have various forms, e.g. a programmable logic array 73 driven by a clock 74. The memory control circuit 72 steers two address generators 76 and 77 respectively generating receive and send addresses for the incoming memory 71 and the outgoing memory 78 in accordance respectively with the protocol of the phone and the protocol of the call processing computer 19 or 38. A data control bus 79 between the PLA 73, the memories 71,78 and the address generators 76,77 serves to transfer data between the adapter unit 2, memories 71,78 and the data output on the RE-292 bus 79a, via internal data bus 81.

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Claims

WE CLAIMt .CLME:

I. A cellular telephone call detail recording system comprising at least one cellular telephone, call detail memory means in said cellular telephone for storing call details; call detail processing means disposed external to said cellular telephone for processing said call details, and connecting means for connecting said cellular telephone with said call detail processlng means.

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2. A cellular telephone call detail recording system according to claim I, wherein said cellular telephone and said call processing means have different data protocols, including protocol conversion means in said connecting means for matching said different protocols.

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3. A cellular telephone call detail recording system according to claim I, wherein said call detail memory means include means for storing at least originating call data, time of originating said calls, and call duration.

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4. A cellular telephone call detail recordlng system according to claim I, wherein said cellular telephone has.a first a protocol for transmltting and receiving call data, said call processing means has a second protocol for transmitting and receiving data, and said connecting means include protocol conversion means for matching said first and second call protocol.

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5. A cellular telephone call detail recording system according %0 claim 1 including call tariff memory means in said call processing means, and call cost computing means commUnlcatlngly associated with sald call tariff memory means for computlng the cost of calls according to said call details.

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6. A cellular telephone call detail recording system according to claim 3 including a clock calendar in said cellular telephone, and power loss protecting means for protecting said call detail memory means and said clock calendar against failure in case of loss of memory.

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7. A cellular telephone call detail recording system according to claim 3, including a plurmllty of cellular telephones, wherein each of said cellular telephones has a unique Identity number stored in said call detail memory means.

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8. A cellular telephone call detail recordln system according to claim I including a mainframe computer in said call detail processing means.

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9. A cellular telephone call detail recording system according t clalm I, including a personal computer In sald call detail processing means.

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I0. A cellular telephone call detail recording system according to claim I, including call billing computing means for computing call billing data connected to said call processing means, and a printer connected to said call billing computing means for computing call billing data.

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II. A cellular call detail recording system according to claim 4, wherein said second protocol is an RS232 protocol.

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12. A cellular telephone detail recording system according to claim 6, including at least one electrically alterable programmable read-only memory (EEPROM) in said power loss protecting means.

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13. A cellular telephone for connection to a call detail processing system, comprising call detail memory means for storing call details, and connecting means for connecting said call detail memory means with the call detail processing system.

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14. A cellular telephone according to claim 13, Includin a clock calendar communlcatlngly connected with said call detail memory means.

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15. A cellular telephone accordlng to claim 13 including call limiting means connected to said call detail processing eans for limiting call billing to a given number of billable calls.

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16. A cellular telephone 1 according to claim 13 including a number assignment module in each cellular telephone.

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17. A cellular telephone according to claim 13 including call restriction means in said telephone for restricting given classes of calls.

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18. A cellular telephone call detail recording system according to claim i, including a user-programmable resale tariff in said call processing means.

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19. Method of recording call detail data for a cellular telephone call detail recording system, which includes a call detail memory in each cellular telephone, an arrangement for processing call detail data in a call processing computer, and a protocol conversion unit for converting the call detail data from the protocol of the phone to the protocol of the call processing computer, the method which comprises! (a) entering into the cellular phone a called number; (b) storing the call detail data in %he call detail memory:

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-" (c) converting in the protocol conversion unit the call detail data from the phone protocol to the protocol of the call procesSlng com- puter; (d) and printing a billing statement.

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20. Method according to claim 19, which further comprises the steps of (a) incrementing a call counter for each entered called number; (b) determining if the call counter is full: and (e) rejecting billable calls if the call counter is full.

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21. A cellular telephone call detail recording system substantially as hereinbefore described with reference to the accompanying drainwgs.

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22. A method of recording call detail data substantially as hereinbefore described with reference to the accompanying drawings.

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