Method for locking to the user's card in a portable radio telephone

Abstract: The invention relates to a method for the use of a portable radio telephone, which has a processor (4) controlling and super­ vising the operation, a keyboard (7) and a display (6), and a card reader (3), in which case, when the radio telephone is being used, the user identification data required by the radio telephone system are read from the card (1). The identification data (21) of the card (1) of the user authorized to use the radio telephone con­ cerned are recorded in the non-erasable memory (5) of the processor (4), whereupon the radio telephone shifts into a mode locked to this card in such a way that its use is possible with only a certain card (1). By means of this method, protection is achieved against unauthorized use of the radio telephone.

Description: The invention relates to mobile radio telephones, including portable radio telephones and to a method for restricting the use of a mobile radio telephone including a processor, which controls and supervises the operation of the telephone, a memory, a keyboard, and a card reader for receiving a data card and for reading user identification data stored thereon. Such a radio telephone is operated in a public radio telephone network and when the radio telephone is set up for a telephone connection, the user identification data required by the radio telephone system is read from the present card inserted in the card reader. One example of such a radio telephone is the telephone working in the German NETZ-C network. The magnetic card required for the use of a NETZ-C radio telephone is a plastic card, the size of a normal credit card, provided with a magnetic strip. This card has all the information required by the system regarding the user. The possessor of the card may feed his card into any NETZ-C telephone and use the telephone with his own identification code, without the system knowing anything about the origin of the telephone itself. A document entitled "Die Mobilstation in Spannungsfeld von Innovation, Rationalisierung and technischen Anforderungen" is considered relevant to the foregoing discussion. Owing to the above, stealing a portable telephone may become tempting. If the thief is not caught red-handed, tracing the telephone later is nearly impossible. The object of the invention is to provide sufficient protection in the telephone itself against unauthorized use. According to a first aspect of the invention, the method is characterized in that the user identification data is read by the card reader from the data card and stored in the memory, in that the radio telephone has a locked mode, in which the radio telephone can be locked to the data card, such that subsequent use of the radio telephone is possible only in conjunction with the data card present in the card reader at the time of locking, and in that the telephone is returned to an unlocked mode, only in conjunction with the data card from which the identification data was stored in the memory at the time of locking. According to a second aspect of the invention, the radio telephone is characterised in that the telephone has a locked mode, in which the radio telephone can be locked to the data card, whereby the user identification data is recorded into the memory from the data card and use of the telephone is only possible in conjunction with the data card and the telephone can only be returned to the unlocked mode in conjunction with the data card from which the identification data was recorded in the memory at the time of locking. Protecting a telephone against unauthorized use is known per se , but the question has always been of locking the telephone apparatus itself or its operation. However, the locking of the telephone apparatus alone does not provide sufficient protection, since opening the locking code is in principle possible by experimenting with a sufficient number of codes, if the telephone allows the locking code to by keyed in using any card. An example of such a method is given in the document entitled JP-A-5868331, Patent Abstracts of Japan, vol. 7, no. 158, 1983. According to the invention, the radio telephone thus has, available for the user to choose, a locking level the activation of which locks the telephone to the magnetic card in the card reader at that moment. The telephone functions completely normally as long as the correct card is in the telephone, but if an attempt is made to use the apparatus with a wrong card, its operation is prevented. If the telephone locked to a card is stolen together with the card, calls made using the card concerned can be prevented at the system level. In another embodiment of the invention, a locking key is provided in the keyboard for the user to press in order to shift the radio telephone to the locked mode and out of it. According to the invention it is also possible to use for the locking for example a four-digit code by means of which the card locking is activated. The locking code and the identification code on the card may also be recorded in the indelible memory of the telephone. After the card is fed in, the identification code on the card is compared with the identification code recorded in the memory, and when the card is the correct one the telephone functions normally but, in the case of a wrong card, operation is prevented. The unlocking can be done with the same card as was used for activating the locking, by keying in the correct locking code. A mobile radio telephone may be made up of a separate operating apparatus (a handset) and a radio unit, each of them having a separate processor. In this case the locking concerns both the operating apparatus and the radio unit. By this solution a protection has been achieved in which both the operating apparatus and the radio unit are locked to the same card, in which case not even the stealing of the operating apparatus alone would be worth while. In the event that the operating apparatus does not have its own separate processor, the locking is implemented in the processor which controls the whole telephone. Such one-processor apparatus could be, for example, hand telephones without a separate operating unit. The card locking can be implemented completely via the program. The card locking is seen on the user interface as only one locking level, which the user may select when he so desires. All that is needed additionally is routines for the identification comparison and for preventing the functioning of the telephone. The user card may be a plastic card, the size of a credit card, provided with a magnetic strip, or some other card suitable for the purpose, for example a so-called "intelligent" card provided with a processor. The method according to the invention is described below with the aid of an embodiment example depicted in the drawing. In the drawing, Figure 1: a block diagram of the principle of a portable radio telephone to the extent that it pertains to the invention; Figure 2: a representation of the principle of the identification data contained in the user's magnetic card; Figure 3: an illustrative picture of the comparison of the locking code in the memory and the code which is fed in; and Figure 4: a block diagram of the principle of a portable radio telephone when the apparatus is made up of a separate operating apparatus and a radio unit. The method works in such a way that, when the user wishes to lock the radio telephone depicted as a block diagram in Figure 1 to a certain magnetic card 1, he feeds the card into the magnetic card reader 3 in the telephone, activates the locking by pressing the locking key 8 in the keyboard, and keys in a four-digit locking code from the keyboard 7. At this time the telephone number (Figure 2) or its part 12 on the card 1 is recorded, together with the locking code 22, into the indelible memory 5 of the telephone. (The data contained in the magnetic card depicted in Figure 2 pertain to the use of the radio telephone system, which is not explained here in greater detail.) When the magnetic card 1 is fed into the card reader 3 the next time, before the initiation of the registration into the network the card number 21 recorded in the memory 5 and the number 31 in the card which is fed in are compared. If the numbers agree in the comparison of Figure 3, the operation proceeds normally. But, if the card 1 is wrong, i.e. numbers 4′-8′ (31) differ from numbers 4-8 (21), the telephone will not register in the network and will not accept any commands from the keyboard 7. Thus the unauthorized use of the radio telephone, without the correct magnetic card 1, is more or less completely prevented. It is possible to unlock the card locking by activating the unlocking by means of key 8 in the keyboard and by keying in the locking code 22 given at the time of the locking. The operation of the parts of the radio telephone and, for example, the keying in, recording and comparison of the numbers are controlled by a microprocessor uP (4) in a manner known per se , not explained here in greater detail. Since according to Figure 4 the mobile radio telephone is made up of a separate operating apparatus (=handset) and a radio unit, each having its own processor 4a and 4b, the locking concerns both the operating apparatus and the radio unit. This means that the same identification code (shown in Figure 3) has been recorded in the indelible memories 5a and 5b of both the operating apparatus and the radio unit. After the feeding in of the card 1, both the operating apparatus and the radio unit compare the identification information in their memories to both the identification code received from the card and that keyed in. Thereafter the processors of both units exchange information regarding the correctness of the identification code according to a certain data transfer protocol; both processors must agree regarding the correctness of the identification code before a call is initiated normally. According to the invention, the disadvantages of conventional locking, mentioned earlier, have been eliminated in such a way that the telephone will not register in the network and will not accept commands from the keyboard, i.e. the telephone is completely "dumb", if a wrong card 1 is fed into the card reader 3.

Claims: A method for restricting the use of a mobile radio telephone, including a portable radio telephone, comprising a processor (4), which controls and supervises the operation of the telephone, a memory (5), a keyboard (7), and a card reader (3) for receiving a data card (1) and for reading user identification data (21) stored thereon, characterised in that the user identification data is read by the card reader (3) from the data card and stored in the memory (5), in that the radio telephone has a locked mode, in which the radio telephone can be locked to the data card, such that subsequent use of the radio telephone is possible only in conjunction with the data card present in the card reader at the time of locking, and in that the telephone is returned to an unlocked mode, only in conjunction with the data card from which the identification data was stored in the memory at the time of locking. A method according to any preceding claim wherein, when the radio telephone is in the locked mode, at any subsequent insertion, into the telephone, of a data card having user identification recorded thereon, the user identification data is read from the subsequently inserted data card and compared to the user card identification data from the initially inserted data card stored in the memory and operation of the radio telephone is prevented if the user identification data from the subsequently inserted data card and the user identification data from the initially inserted data card are not the same. A method according to claim 1 or claim 2 wherein the telephone is shifted into and out of the locked mode by a user of the telephone pressing a locking key (8) provided on the keyboard. A method according to any preceding claim wherein the telephone is shifted into the locked mode by the user keying in a multi-digit code (22) via the keyboard, the multi-digit code being stored in the memory with the identification data. A method according to claim 4 wherein the telephone is returned to the unlocked mode by keying in the multi-digit code input and stored in the memory at the time of locking, whereby the keyed multi-digit code and stored multi-digit code are compared and the telephone is returned to the unlocked mode in response to match between the compared multi-digit codes. A method according to any preceding claim wherein the identification data comprises the whole or part of the user's telephone number. A mobile radio telephone, including a portable radio telephone, comprising: a processor (4) which controls and supervises the operation of the telephone; a memory (5); a keyboard (7); and a card reader (3) for reading a data card (1) having user identification data (21) recorded thereon; characterised in that the telephone has a locked mode, in which the radio telephone can be locked to the data card, whereby the user identification data is recorded into the memory from the data card and use of the telephone is only possible in conjunction with the data card, and the telephone can only be returned to the unlocked mode in conjunction with the data card from which the identification data was recorded in the memory at the time of locking. A radio telephone according to claim 7 comprising means for comparing user identification data read by the card reader from a data card inserted into the telephone subsequent to the telephone having being shifted into the locked mode with the user identification data from the data card inserted during the locking procedure and stored in the memory, and means for making the telephone inoperable in response to a mismatch between the compared user identification data. A radio telephone according to claim 7 or claim 8 comprising a key provided on the keyboard for shifting the telephone into and out of the locked mode. A radio telephone according to any of claims 7 to 9 comprising means, operable in response to a multi-digit sequence keyed in via the keyboard and stored in the memory for shifting the telephone into the locked mode. A radio telephone according to claim 10 comprising means for comparing a keyed in multi-digit code with the stored multi-digit code and means operable in response to a match between the compared multi-digit codes to return the telephone to the unlocked mode. A radio telephone according to any of claims 7 to 11 comprising a handset and a radio unit, each having means for comparing user identification data read by the card reader from a data card inserted into the card read subsequent to the telephone being shifted into the locked mode with the user identification data from the data card inserted during the locking procedure and stored in the memory, and means for rendering the telephone inoperable in response to a mismatch between the compared user identification data.

Inventors: KEMPPI YRJOE, KEMPPI, YRJOE, Kemppi, Yrjö
Applicants: NOKIA MOBILE PHONES LTD, NOKIA MOBILE PHONES LTD.
Application year: 1988
Main classification: H04M1
IPC codes: H04M1, H04W88