The invention relates to a method for calling by a terminal ofa mobile communication system, like a card- controlled mobile phone, according to the ingress of claim 1

Cellular phones and mobile stations have already been used for decades and the principle of mobility has always been associated with cellular phones

It is previously known that the user ofa mobile station is identified by an identity or memory module, a so- called SIM-card, to be entered into the station As examples of this can be mentioned almost all cellular phone networks serving the card-controlled mobile stations, e g the GSM-network

It is also known to arrange into one identity or memory module two identification or service disposal data An example of this gives the publication SE 467559 concerning the solution, where the SIM-card of a GSM- phone has two identities, IMSI1 and IMSI2, whereby the subscnber uses either of them according to his selection In compliance with this publication the SEM-card is entered to the reader in the first position, I e the first end ahead, whereby IMSI 1 is used, and IMSI 2 can be used, when the SIM-card is placed into the reader in another position, I e another end forward The mobile station can alternatively be provided with a selecUng switch for the selecUon of IMSI 1 or IMSI2

It is also known to use another identity module together with the identity module already entered into the mobile station or already existing there, whereby the identity module introduced to another reader displaces the identification data ofthe previous identity module and the deliverer of this other identity module is identified as a user ofthe mobile station Reference is made to the publication GB 2269512 disclosing an arrangement, in which more than one memory module, l e datacard, can removably be connected to the mobile station having a data processor employing readers in predetermined succession, or the readers receive a corres-pondmg number of memory modules, I e SIM-cards According to this publication individual readers may receive datacards of different physical sizes The above-mentioned succession can be rearranged auto- matically, when a card or a reader is detached or attached The user can also modify the succession e g by a menu selection

The starting point ofthe present invention is the limitation ofthe movability and engagement ofthe mobile station to a fixed place, and the pπmary goal of the invention is to provide a novel method for calling by a terminal ofa mobile communication system, like a card-controlled mobile phone, enabling a service of local subscπber type in the cellular phone network, I e to form a wireless local loop, that can preferably be pπced. using a fixed mobile phone

This purpose has been attained by the method according to the invention, the specific features of which are disclosed in the accompanying claims.

According to the present invention the removal of mobility from the mobile phone and the engagement of communications to a certain place and or area have been solved so, that the mobile phone is fastened to a specific teleterminal adapter, i.e dock, which is a device bound to the place, whereat the SIM-card ofthe mobile phone is deactivated and SIM-card in the adapter is activated. SIM-card ofthe mobile phone is thus activated and the mobile phone is restored as a normal mobile station, when it is detached for the adapter, whereby SIM-card in the adapter is deactivated and the adapter can no more function as a teleterminal device.

The advantages ofthe invention include that by it a service of local subscriber type can be realized in the mobile phone network, as in GSM-network. There are no limits, however, for the application ofthe invention also to other cellular networks, in which it is possible to utilize several identifications for the subscriber device and thus for the subscriber. For instance DECT (Digital European Cordless Telecommunications) and PCS- networks in USA can be employed as possible service platforms for the invention.

The invention will be described in the following by a pre-ferable embodiment thereof associated with the GSM (Global System for Mobile Communication) -cellular phone system with reference to the accompanying drawings, in which: Fig. 1 shows a cellular phone fastened to a teleterminal adapter used in the method according to the invention, whereby the phone functions only as a mobile phone bound in certain place or region, i.e. the cellular phone subscriber is a local subscriber;

Fig. 2 shows a cellular phone coupled off from the teleterminal adapter used in the method according to the invention, whereby the cellular phone can be used as a normal movable phone, i.e. the cellular phone sub- scriber is a normal mobile phone subscriber;

Fig. 3 shows the functions of the teleterminal adapter used in the mobile phone and in the method according to the invention, when the service mode is changed from cellular phone subscriber to local subscriber (section A), and - from local subscriber to cellular phone subscriber (section B).

Fig. 4 shows routing of calls by chaining; Fig. 5 shows a block diagram of call chaining.

In the GSM- mobile phone system the subscriber is identified by SIM (Subscriber Identity Module) -card data including the IMSI (International Mobile Subscriber Identity) -symbol. When in the GSM-network calls are formed for the subscriber, it is supposed, that IMSI-data of the subscriber is updated in the VLR (Visitor Location Register)- register of the GSM-network. In this case the subscriber is identified for invoicing and incoming calls are routed to proper location area. IMSI does not comprise a phone number, but the data

needed for the subscriber identification. However, a MSISDN (Mobile Subscriber International ISDN) - number has been connected to IMSI in a HLR (Home Location Register) network element.

The present invention comprises two SIM-cards, to both of which has been associated individual IMSI-data and individual MSISDN-numbers determined in HLR. To the system belong also a GSM- terminal device (later on MS), external adapter and teleterminal adapter, i.e the MS dock. SIMI-card is situated in the adapter having the IMSI 1 -data. SIM2-card having the INSI2-data, is in the MS.

User of MS may be identified in the GSM-network on grounds ofthe both IMSI-data and also on the phone- and adapter-related IMSI-data. When MS is in usual cellular phone use. IMSI2 is activated in the network, see FIG. 1. If MS is coupled to the adapter, the SIMl-card is coupled on instead of the phone's SIM2-card and the subscriber is identified by the IMSIl-data, see FIG. 2. In order to activate IMSI1, the MS must be coupled to the adapter and the SIMl-card. For the activation and deactivation of IMSI's can be used either the IMSI detach attach function or the Periodic Location Update function, which both are known by themselves and specified in the GSM-spesification. The adapter gets its operational voltage from a separate accumulator or electrical network and it includes also a charger for charging the accumulators of the cellular phone.

According to the basic principle ofthe invention it is tried to attain the goal, that for a cellular phone sub¬ scriber a service can be realized, by which the subscriber may have both usual mobile phone calls and calls located in a certain place and corresponding the local subscriber by the aggregate ofthe cellular phone and the adapter. The adapter adapts the cellular phone to a 2-wire coupler, into which is connected an analogical, PSTN-compatible phone serving as a control part for the calls. Calls can also be made through the terminal device itself or by a separate receiver using the keyboard ofthe cellular phone for selection of numbers and to satisfy other needs of the telephone communication.

The invention includes therefore: a) transfer from a cellular phone subscriber to a local subscriber (and vice versa), b) routing of incoming calls to MSISND-number in use at the time, both c) prevention of mobility from the local subscriber.

In FIG. 1 the mobile station MS has been attached to the teleterminal adapter (in the following "adapter"), whereby a data transmission bus is formed between the mobile station and the adapter. The mobile phone reads from the SIM-card SI I the IMSIl-data needed for the identification ofthe local subscriber. Then besides the SIM-card SIMI also a movement indicator is coupled to the MS, whereby the use of the phone as a mobile phone is prevented and GSM-service bound to a place or certain location area is formed, or the extension gets the qualities ofthe local subscriber. In FIG 2 the MS functions as a conventional terminal device for cellular phone service. Cellular phone is coupled off from the adapter and the movement indicator, whereby it uses the SIM-card SIM2 intended for the cellular phone service.

Reference is made to FIG 3 and transfer from a mobile station subscriber to a local subscriber, section A, and from a local subscriber to a mobile station subscriber, section B, is disclosed.

In FIG 3, section A), there is shown a method, by which transfer is made from a mobile station subscriber to a local subscriber. When the MS is coupled to an adapter, the MS effects the IMSI detach function according to the GSM-system for the IMSI (IMSI2) on the SIM-card of the cellular phone service. Thereafter the MS changes over to a local subscriber by making the IMSI attach function according to the GSM-system for the IMSI (IMSI1) on the SIM-card ofthe local subscriber, located physically in the adapter.

In FIG 3, section B), there is shown the transfer ofa local subscriber to a cellular phone subscriber. When the MS is detached from adapter, the MS effects the IMSI detach function according to the GSM-system for the IMSI (IMSI1) on the SIM-card ofthe cellular phone service. Thereafter the MS changes over to a cellular phone subscriber by making the IMSI attach function according to the GSM-system for the IMSI (IMSI2) on the SIM-card ofthe local subscriber, located physically in the adapter.

With reference to FIG's 4 and 5 control of incoming calls by chaining is described.

In FIG 4 has been shown routing ofthe call by an arrow diagram in different situations, as follows: section a) first IMSI is reached, section b) first IMSI is in the "detach"-state and the other one is reached, and section c) neither IMSI's are reached, but the call is guided to a third number, e.g. the answering machine.

In FIG 5 has been shown a block diagram concerning the control ofthe call and its task in the chaining ofthe MSISDIN-numbers. For the local subscriber has been specified for the call-control an own chain, including: 1. MSISDIN1 of the local subscriber's number

2. MSISDIN2 ofthe cellular phone subscriber's number

3. third number (e.g. answering machine)

Control of the incoming calls is realized in a separate intelligent center ofthe cellular phone network or in a sepa-rate registering device (IN-center), where all the calls made from any phone to the cellular phone subscriber or the local subscriber will be guided. Calls come through a normal telephone network (PSTN) to the intelligent center, which guides the call further to the cellular phone extension. If the called subscriber is in the "detach"-state, the intelligent center guides the call to another possible number.

The network signal between the intelligent center and the cellular phone extension can transfer the "detach"- state. For example the Finnish national TUP93 -signal (SFS standard) includes in the addiuonai information ofthe EUM-message the announcement "cellular phone subscriber is not reached". The "detach"-data marked in the figure comprises a normal Gateway MSC function in the Send Routing Info -procedure specified in the GSM-specification, when the reached subscriber is in the "detach"-state and he has no active call transfers.

The only functional difference is, that in addition to the announcement "you called a cellular phone, which is not contacted right now", an EUM-message is also dispatched provided with proper additional information.

When a call comes to the intelligent center, it begins to ring the outgoing or queuing sound to the subscriber. It forms simultaneously a further call to the number selected by the A-subscriber. If the B-subscriber can be reached, it connects the call through and gives the call-control to the cellular phone exchange. If the cellular phone ofthe B-subscriber cannot be reached, the cellular phone extension sends the EUM-message back, so that the intelligent center can begin to form a new call to the MSIDSDSN2-number. If the number can be reached, it connects the call, otherwise it forms a call to the next number in the list.

A list of reachable numbers is specified as subscriber-related to the intelligent center. The list includes at least two numbers (MSISDN1 and MSISDN2). The list may additionally have also other numbers, which have been marked to the list in the sequence of reachability. When a call comes to the intelligent center, this tries to reach the subscriber from the listed numbers and the A-subscriber hears the outgoing sound, except the case, if it is tried to route the call to the last number in the list. In this case the call is connected through the intelligent center and thus the A-subscriber hears all possible outgoing/queuing announcement etc. sounds of the call belonging to the latest subscriber ofthe chain.

The intelligent center may form a call to the next number in the list also in a "not answering"-situation after a certain predetermined time, and in the "reserved"-siruation a "reserved"-sound can be ringed to the A- subscriber or a call can be formed to the next listed number.

Calls ringed to the number MSISDN 1 ofthe local subscriber are guided first to the IN-system, wherefrom an inquiry is made to the VLR MSC ofthe GSM-system concerning the IMSI (IMSIl) status ofthe subscriber.

If the IMSIl ofthe local subscriber is in the "attached"- state (MS as the local subscriber), the call is con¬ nected according to the GSM-system to the MS and further on through the 2-wire coupler ofthe adapter to an analogical PSTN-phone.

If the IMSIl ofthe local subscriber is in the "detached" -state (MS detached from the adapter) a new inquiry is made from the IN to the VLR/MSC of the GSM-system. If the IMSI2 ofthe cellular phone subscriber is in the "attached"-state, the incoming call is connected according to the signalling of the GSM-system to the MS or the cellular phone subscriber.

If, however, IMSIl and IMSI2 are both in the "detached"-state, the call is transferred to the third number of the chain, e.g. to an answering machine.

Guiding of the calls coming to the number ofthe cellular phone subscπber to the active number takes place bv the pπnciple described above For the cellular phone subscπber it has been specified for call-guiding a separate chain, including (FIG 5)

1 number ofthe cellular phone subscπber MSISDN2 2 number of the local subscπber MSISDN 1

3 third number, e g answeπng machine

Calls ringed to the number ofthe cellular phone subscπber MSISDN2 are guided first to the IN-system, wherefrom an inquiry is made to the VLR MSC of the GSM-system concerning the IMSI (IMSI2) status of the subscπber If the IMSI2 ofthe cellular phone subscnber is in the "attached"-state (MS functioning as the cellular phone subscnber and being detached from the adapter), the call is normallv connected to the cellular phone subscπber

If the IMSIl of the local subscriber is in the "attached"-state (MS attached to the adapter), the call is con- nected to the MS according to the signalling of the GSM-system and further on bv the 2-wιre coupler of the adapter to an analogic PSTN-phone

If. however, the IMSIl and IMSI2 are both in the "detached"-state (MS detached from the adapter), calls coming to cor- responding MSISDN-numbers are chained to a third number, if it is specified This number mav comprise e g the number ofthe answeπng service

The location logic m the adapter controls the movements of the MS dunng the call and also between the calls In this way mobility is taken off from the GSM- mobile station and a place-bound specially pπcable GSM- sen ice is formed

In order to prevent movements of the adapter, the movement indicator can be realized also

- mechanically,

- pro\ iding the power and current supply arrangement ofthe adapter with mains connection

- b\ separate location system, comprising e g a GPS (Global Positioning System), or - electrically monitoπng changes in the system infoπnation or radio signals of the GSM-network

For the invention it is essential to utilize the qualities of the GSM-network in the location The adapter may read from the data transmission bus ofthe MS for the location logic the following system information ele¬ ments of the GSM or the values of the radio signals - identities of own cell and neighbouπng cells (Cell Global Identity CGI)

- field intensity measurements of own cell and neighbounng cells (RXLEV)

- Timing Advance TA

- Base Station Identity Codes BSIC for own and neighbouring base stations

- Absolute Radio Frequency Channel Numbers ARFCN for own and neighbouring base stations

On grounds of these data the location logic ofthe adapter monitors the mobility ofthe MS and the adapter aggregate during the call. If the location logic states that a sufficient change has taken place, for instance because of a change in the timing advance, the adapter disconnects the 2-wire connection and breaks off the ongoing GMS-call and prevents the use ofthe SIMl-card in the adapter for identification ofthe subscriber.

If the location logic finds out that the MS has moved during the calls, the adapter disconnects the 2-wire connection making the analogical phone silent and prevents the use ofthe SIMl-card in the adapter for identification of the subscriber. If the 2-wire connection has been made silent and the SIMl-card locked, so that it cannot be used for local subscriber service, the SIMl-card in the cellular phone is, however, normally available.

Mobility can, as stated above, be mechanically removed. Then the adapter size can be made large or in awkward form. Alternatively the adapter is provided only by a connection for external antenna, as roof or wall antenna. Also the use ofthe mains current as the power source limits the mobility.

The invention has been disclosed above only by one of its preferable embodiment associated especially with a GSM-mobile phone system. This does not, of course, in any way limit the scope ofthe invention, and as will be understood by a person skilled in the art, several modifications and alternatives are possible within the scope ofthe invention defined in the accompanying claims. So it must be specially stated, that nothing limits the application ofthe invention also to other cellular networks, where it is possible to utilize several identifi¬ cations to the subscriber device and thus to the subscriber. For instance DECT (Digital European Cordless Telecommunications) and PCS-networks in USA can be employed as possible service platforms for the invention.