FR2788190A1 - NUMBERING IN A MOBILE RADIOTELEPHONE TERMINAL AFTER AN INTERNATIONAL TRANSFER - Google Patents

Abstract

The invention aims at facilitating the use of called numbers in a subscriber's country of origin, having a mobile radio terminal, when the subscriber is travelling abroad. When the called number NA = 0 NN is not an international number, a country of origin indicator (MCC0) read (S2) in the identity code IMSI of the user and a code (MCCE) of the country where the terminal is located (MS) read (S3) in a local area identifier (LAI) are compared (S4). The called number is not modified (S5) when the country indicators compared are identical. A code CC0 of the country of origin is added at the beginning (S8) of the called number when the country indicators compared are different, so that the number transmitted by the terminal is in the international format (S9).

Description

1i 2788190 Dialing in a mobile radiotelephone terminal after a

  international transfer The present invention generally relates to an adaptation of telephone call numbers in a radiotelephone terminal when this transits from an original radiotelephone network to a

  foreign radiotelephone network.

  It will be assumed in the following description

  that the original radiotelephone network is for example one of the three French national cellular radiotelephone networks (Public Land Mobile Network PLMN) GSM 900 / FRANCE TLECOM, GSM 900 / CEGETEL and DCS 1800 / BOUYGUES TELECOM, and the foreign radiotelephone network is for example located in

Great Britain or Germany.

  As shown in FIG. 1, the French national switched telephone network RTCN is essentially composed of switches with autonomy of routing CAA and between these of transit switches (not shown). Some of the switches CAA serve as gateways between switches in the mobile service MSC of the three aforementioned national radiotelephone networks RRN0, RRN1 and RRN2. One RRN0 of these three radiotelephone networks has its architecture more detailed in Figure 1 and will be considered as the original network with the operator of which a subscriber carrying a terminal

  mobile radiotelephone MS has taken out a subscription.

  A switch of the mobile service MSC in the network RRN0 has a role equivalent to a switch CAA in the network PSTN, and in addition manages the telephone communications for radiotelephone terminals

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  mobile devices located at a given time in its location area. The MSC switch is associated with a VLR visitor location register which contains the subscription and temporary location characteristics of visitor mobile terminals, in fact removable SIM (Subscriber Identity Module) smart cards contained in the

visitor terminals.

  Each MSC switch serves several sub-

  io fixed networks (Network Sub-System NSS) each comprising a base station controller BSC managing the allocation of digital channels to the visiting mobile terminals, the powers of the base stations and the intercellular transfers between base stations. Each BTS base station covers a radio cell or mobile terminals

are at the given moment.

  The national radiotelephone network RRN0 also includes a nominal location register HLR which contains in particular for each MS terminal subscribed to the RRN0 network the international identity of the IMSI subscriber (International Mobile Subscriber Identity), the directory number of the MSISDN subscriber (Mobile Station ISDN Number), the subscription profile, and the number of the VLR visitor location recorder updated during each transfer from the MS terminal between two location areas in the RRN0 network. The HLR recorder exchanges signals with the MSC / VLR switches / recorders through a signaling network with signaling channels SS7 (Signaling System Number 7). The VLR and HRL recorders are also linked to signaling points on the signaling network associated with the PSTN switched telephone network, in particular for signaling

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  communication establishments between a terminal of the RRN1 network and any other terminal of the PSTN fixed network, or of one of the radiotelephone networks

RRN0 to RRN2.

  In FIG. 1, a switched “foreign” RTCE telephone network, for example British or German, and a foreign radiotelephone network RRE served by the RTCE network is also shown diagrammatically. To establish international communications, the national RTCN network includes international transit switches CTI connected to foreign switched telephone networks, such as the RTCE network. Certain radiotelephone networks, such as the RRN2 network, have their own international transit center TSC. Each country is indicated in an international telephone number by a country code CC (Country Code) with one, two, three or four digits, for example 33 for France, 44 for Great Britain, 49 for Germany, 1 for the United States, 352 for Luxembourg, etc. Each subscriber has a unique MSISDN directory telephone number in the global numbering plan which is of the form CC NN where NN denotes the significant national number. For example in France, NN is equal to I AB PQ MCDU, where I denotes the long distance code, i.e. the national destination code of the network to which the subscriber has subscribed, for example 1 for the Ile region from France, or 4 for the Southeast region, 6 for the national radiotelephone networks, and AB PQ MCDU the subscriber number assigned by the network operator. When establishing a national call between two mobile or fixed terminals of the national PSTN network, the national number of the called party transits between the corresponding switches MSC

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  and / or CAA. When establishing an international call between a terminal of the national network PSTN and a terminal of the foreign network RTCE, the international number of the foreign called MSISDN = CC NN transits through the corresponding switches MSC and / or CAA of the network RTCN, the international transit center CTI, and the corresponding switches

  CAAE and possibly MSCE from the foreign RTCE network.

  At the level of the subscriber himself, in this case a mobile radiotelephone terminal MS, the dialing of a telephone number called NA is somewhat different and currently presents three possibilities. FIG. 2 shows a numbering algorithm according to the prior art for the composition of a SET UP establishment message which is transmitted by the mobile terminal MS to the switch MSC after call validation by a specific key, for example a terminal keyboard navigation key, request a radio channel, and exchange authentication messages and

encryption.

  It is recalled that a mobile radiotelephone terminal MS of a subscriber comprises a removable microprocessor module, called a SIM chip card connected to a bus of the digital microprocessor circuit in the terminal, the bus serving the keyboard, the screen and device terminals of the mobile terminal. The SIM smart card (Figure 1) mainly contains a microprocessor, a ROM memory including the operating system of the card and specific application algorithms, a non-volatile EEPROM memory which contains all the characteristics linked to the subscriber such that the IMSI identity, the profile

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  subscription, the list of numbers called with their names, security data (confidential code), etc., and a RAM memory used to process the data to be received from and transmitted to the digital circuit of the terminal. In particular, the algorithm of FIG. 2 is managed by the ROM memory in collaboration with the directory of telephone numbers and the last number dialed in the EEPROM memory, in order to dial the

  SET UP establishment message in RAM memory.

  In the first step E1, the subscriber chooses between manual dialing of the number of the called party NA written in the EEPROM memory in the next step E2, or else by selecting from the menu on the terminal screen, using keys or by voice commands if the terminal has a voice recognition device, the directory of telephone numbers already saved in EEPROM memory after having searched for the name of the called party in step

following E3.

  The number of the called party NA dialed on the keyboard or selected and validated by reading in EEPROM memory has the following form: NA = EN NN = EN I AB PQ MCDU. EN denotes a header which has one of the following three configurations: 1) EN = 0 = long distance prefix, when the subscriber has dialed or selected only a 10-digit French "national" number, for example 0 NN = 01 45 81 74 57 for a called party in the Ile de France region, starting with the predetermined number 0; 2) EN = 00 CC, when the subscriber has dialed or selected an MSISDN number preceded by the international prefix 00 which is not accepted in all foreign RTCE telephone networks, for example 00

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  49 NN for a called party in Germany, or 00 33 NN for a national called party in France; 3) EN = + CC, when the subscriber has dialed or selected an MSISDN number preceded by the international code +, symbol affixed to the star key * on the keyboard, which is recognized in all foreign telephone networks RTCE, for example + 44 NN for a called in Great Britain, or + 33 NN for a

called national in France.

  The next step E4 examines the format of the number called NA and particularly of the header EN after

  reading of the called number NA in the EEPROM memory.

  If the called number NA is OI AB PQ MCDU, that is to say with EN = 0, it is in open format and a TON (Type Of Number) field occupying bits 5, 6 and 7 in a third byte of the SET UP message, the next five bytes of which include the digits of the national number NN in binary coded decimal code BCD, is set to 0: TON = 0 in step E5. Similarly, if the called number NA is 00 CC NN, it is in open format and the TON field is TON = 0 in step E5. In these two cases, the called number NA is in step E6 inserted without change in the SET UP message which is transmitted by the mobile terminal MS to the switch of the mobile service MSC to which it is

  temporarily attached to the final stage EF.

  When the called number NA contains the international code +, that is to say in the international format + CC NN in step E4, the next step E8 sets the number type field TON to 1: TON = 1, and removes the international prefix + in the number called NA. The number of the called party MSISDN = CC NN is inserted in the next step E9 in the SET UP establishment message which is finally transmitted

  by the mobile terminal MS in step EF.

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  In the MSC mobile service switch to which the MS radiotelephone terminal is attached, the TON field in the SET UP message is read in order to insert the significant national or international number in the call message to the other switches in the direction of called. If TON = 0, the national prefix 0 is removed and the significant national number NN is inserted in the call message, or the international prefix 00 is removed and the significant international number CC NN is inserted in the call message except when the CC code is that of the country of origin, ie CC - CC0 = 33 for France. If TON = 1, the international number received in the SET UP message is inserted without change in the call message when the CC code is that of a foreign country, in this case different from that CC0 = 33 for France. When TON = 0 and CC = 33, or TON = 1 and CC = 33, the code of the country of origin, in this case that of France, is removed, and only the significant national number NN is

inserted in the call message.

  When the subscriber of the mobile terminal MS travels abroad and is schematically in MS 'in FIG. 1, if he wishes to establish a communication through a radiotelephone network RRE attached to a foreign switched telephone network RRE, the subscriber can only use the numbers called in international format NA = + CC NN, or if necessary in some countries, the numbers called in open format NA = 00 CC NN. All the called numbers which are numerous to be saved in the open format 0 NN cannot be used and must be dialed again by preceding them with

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  code + or prefix 00, followed by the country code

  of origin, in this case 33 for France.

  In addition, the subscriber who is used to storing called party numbers in his country of origin in the open format 0 NN, will be tempted to validate the reading of such numbers, and after receiving an invalidation message or having conversed with an undesired stranger called, will be forced to renumber, or to a new memorization in

  EEPROM memory with the format 00 CC0 NN or + CC0 NN.

  The present invention remedies these drawbacks when the subscriber travels abroad, so that any number called from the country of origin already stored in the mobile radiotelephone terminal or dialed in the open format 0 NN is put in the form of an international number CC0 NN for the country of origin, without disturbing or modifying the number adaptation functionalities in the foreign switches MSCE and CAAE and national switches CAA and MSC crossed by the call messages from the terminal radiotelephone. To this end, a dialing process in a radiotelephone terminal is characterized by the following step when a called number is not an international number: - add a country of origin code at the start of the

number called.

  According to this first simple embodiment of the invention, the addition of the code of the country of origin, or of the country of residence, of the subscriber possessing the radiotelephone terminal can be carried out when dialing the national called number to the

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  format opened by means of the terminal keyboard or by voice recognition in the terminal, i.e. the step of adding precedes a writing of the called number, as the last number dialed, in a memory of the terminal . According to another embodiment, the numbering method further comprises the following steps when a called number is not an international number: - compare a country code of origin with a code of the country where the terminal is located, - do not change the number called when the country codes compared are identical, and carry out the said step of adding when the

  country codes compared are different.

  In this other embodiment, the number called is first dialed and read from the terminal's memory, or is read from the directory of telephone numbers already stored in the terminal's memory, and the step of comparing follows reading.

  of the number called in the terminal memory.

  In this way, the numbers called in the country of origin, or of residence, of the subscriber in open format are still used and are converted into international format only when the subscriber is abroad. The country code of origin is read, either in a subscriber identity stored in the terminal and frozen as soon as the subscription is subscribed, or in a specific field in a memory of the terminal which is programmable by the subscriber in order to preferably enter the code of his country of residence o 2788190 for which many telephone numbers are stored in the terminal, rather than the code of the country of subscription contained in the subscriber identity and which can be different from the country code of residence. The country code where the terminal is located is read in a location area identity stored in the terminal and updated with each location area transfer and therefore particularly during a network transfer

  national to a foreign network or vice versa.

  According to another variant, the method comprises the following steps before the step of comparing, selecting a radiotelephone network of the country where the terminal is located in a table of networks stored in the terminal, and reading the code of the country where the terminal is located. terminal in the table corresponding to the selected network. The select step involves the subscriber and this variant is semi-automatic compared to the first variant relating to the reading of country code in the location zone identity which

is automatic.

  In practice, a long distance prefix is included at the beginning of the called number. The method then includes removing the long distance prefix from the called number before the adding step. According to said other embodiment, the method may include removing the long distance prefix from the called number before the step of adding when the country codes compared

are different.

  The code of the country of origin is preferably read in a specific field of a programmable memory of the terminal, or according to said other embodiment, can be read in correspondence with the country code of it 2788190 of origin in a table of countries stored in the terminal. The number called processed, according to said other embodiment of the method of the invention, is inserted into an establishment message which contains a number type field, that is to say indicating the open or international format. The method then includes setting the number type field to an international format state when the country codes

compared are different.

  Preferably, after the step of adding the code of the country of origin, the method comprises a step of adding an international code to the beginning of the called number in order to write it as an international number in a memory of the terminal, especially in place of the initial called number when it is already registered in the directory of telephone numbers. When a called number is a number preceded by an international prefix or code, the international prefix or code is removed from the called number. The number type field is set to an international format when the called number is a

  number preceded by the prefix or international code.

  Preferably, the step of comparing follows a reading of the called number in a memory of the terminal. The invention also relates to a radiotelephone terminal or a subscriber identity module insertable into a radiotelephone terminal comprising a memory numbering algorithm for implementing the numbering method.

according to the invention.

12 2788190

  Other characteristics and advantages of the present invention will appear more clearly on

  reading the following description of several

  preferred embodiments of the invention with reference to the corresponding appended drawings in which: - Figure 1 is a schematic block diagram of radiotelephone networks in the context of an international telephone communication, already discussed; - Figure 2 is a numbering algorithm in a mobile radiotelephone terminal according to the prior art already discussed; and - Figure 3 is a numbering algorithm in a mobile radiotelephone terminal according to

the invention.

  In the numbering method according to the invention shown in FIG. 3 and implemented in the form of software in the ROM ROM of the SIM card (FIG. 1) of the radiotelephone terminal MS of the subscriber, we find steps E1 to E9 and EF included in the algorithm of FIG. 2 implemented in a SIM microprocessor card of a mobile radiotelephone terminal according to the technique

anterior.

  The successive steps E7, E8, E9 and EF are accomplished when the called party number NA begins

  by the international code + in step E4, i.e.

  say in international format NA = + CC NN, with either CC country code that of the country of origin, CC0 = 33 for France, where the subscriber possessing the SIM card has subscribed, or that of a foreign country, such as CC = 44 for the

  Great Britain or CC = 49 for Germany.

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  Also, the successive steps E4, E5, E6 ′ = E6 and EF already described with reference to FIG. 2 are carried out when the called party number NA begins with the international prefix 00 and is in the open format NA = 00 CC NN, that the CC country code is that CC0 = 33 of the country of origin, or that

  from a foreign country, for example 44 or 49.

  Indeed, these two configurations of called number remain unchanged since the first is acceptable by all telephone networks worldwide and the second is acceptable by most foreign telephone networks. The subscriber re-uses these two configurations of the called number when he is traveling abroad, for example with his mobile radiotelephone terminal located in MS 'in the coverage area of a switch of the MSCE mobile service of the foreign radio network RRE shown in Figure 1, to call a called party located in a foreign country, including the country where the subscriber is located, or even located in the country of origin of the subscriber, in this case the France. Alternatively, so that the number called is acceptable in all countries, even when it initially begins with the prefix 00, step E6 ′ is replaced by a step E6 ″ during which the TON field is set to 1 and the prefix 00 is deleted in order to insert TON = 1 and CC NN in the SET UP message in the next step E9, as shown in lines

dotted in Figure 3.

  When the subscriber traveling abroad, outside his country of origin, France, wishes from his mobile radiotelephone terminal located in MS '(Figure 1) to request the establishment of a

14 2788190

  telephone communication with a called party located in the country of origin of the subscriber, without changing their dialing habits, the subscriber dials on the keypad, or if necessary by dictation, the number of this called party in step E2, or searches for the name of this called party, if necessary by dictation, in the directory of the SIM card of his terminal MS and validates it to display the number of the called party on the screen of the terminal MS in step E3. The number of the called party in the country of origin begins with the long distance prefix 0 and is in the open format NA = 0 NN, for example 04 42 36 50 00. The MSCE switch of the foreign radiotelephone network RRE removes the prefix 0 from the NA number received in the SET UP establishment message (step E6) according to the prior art, so that the foreign telephone network RTCE establishes a communication with an unwanted called party located in the country where the subscriber is located, or else does not recognize the prefix 0 and then refuses to establish the requested communication. Anyway, the subscriber does not communicate with the called party called in the country

  original according to the prior art.

  As shown in FIG. 3, the invention introduces steps Si to S9 and a step E6 'analogous to step E6 and between steps E5 and EF

when NA = 00 CP NN.

  When the format of the called number is open and after the type of number field TON (Type of Number) is set to 0 in step E5, the step Si distinguishes the national or international character of the header EN in the called number NA = EN NN read in the EEPROM memory of the SIM card. If the NA number begins with the international prefix, i.e. with the EN header equal to 00 CC, the called number read

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  NA = 00 CC NN, for example with the country code CC equal to 44, 49 or 33, is entered with the field TON = 0 in the SET UP establishment message in step E6 'and is sent by the terminal MS 'to the foreign mobile service switch MSCE in step EF, as in the prior art shown in steps

  successive E5, E6 and EF in Figure 2.

  If step S1 locates the long distance prefix 0 at the beginning of the called number NA in the form NA = 0 NN = OI AB PQ MCDU, the following three steps S2, S3 and

  S4 are made in RAM memory of the SIM card.

  Step S2 reads from the EEPROM memory of the SIM card an MCC0 (Mobile Country Code) code of the subscriber's country of origin, in this case MCC0 = 208 for France, in the first three-digit field of the international identity of the IMSI subscriber

  (International Mobile Subscriber Identity).

  The IMSI identity also contains in a second field, the code MNC0 (Mobile Network Code) of the radiotelephone network of origin RRN0 on which the subscriber depends. As a variant, instead of reading the code MCC0 of the country of origin in which the subscriber has subscribed, step S2 reads a specific field in the EEPROM memory o the subscriber has stored the code of the country o the subscriber usually resides, which can be different from the country where the subscriber subscribed. For example, for a French subscriber who has taken out a subscription in France with the operator FRANCE TELECOM and resides in Germany, and therefore having registered German called numbers 0 NN in open format, for example 06721 99 50 41, l country code in the IMSI subscriber identity corresponds to France, and

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  the country code in said specific field read in step S2 according to this variant corresponds to Germany; according to this example, the subscriber is considered to be abroad when he is in a territory outside of Germany. Step S3 determines the country where the subscriber's terminal is located at the time he requests

  establishing communication.

  It is recalled that the BTS base stations (FIG. 1) broadcast periodically in respective beacon channels (Broadcast Control CHannel BCCH)

  the identities of their location zones.

  The identity of a Location Area Identification (LAI) zone includes in particular an MCC0, MCCE (Mobile Country Code) code with three digits of the country where the base station is located, and more generally where the area of Location (Location Area) of the MSC, MSCE mobile service switch where the base station is located as well as an MNC0, MNCE (Mobile Network Code) code for the RRN0, RRE radiotelephone network which includes the base station. The subscriber's mobile terminal periodically scans the beacon channel of the cell where it is located. When the radiotelephone terminal decides to change (handover) of cell during the periodic measurement of the carrier frequencies communicated by the list contained in the beacon channel on which it is calibrated, the radiotelephone terminal saves the LAI identity of the new cell in EEPROM memory on which it has just set, and communicates its location to the old location recorder

of visitors VLR, VLRE.

  When the subscriber travels abroad, the list of beacon channels no longer contains the network number MNC0 in their LAI identities

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  radiotelephone of RRN0 origin. The mobile terminal MS 'searches in the carrier frequencies of

  radiotelephony, the best received beacon channel.

  The LAIE identity of the new location area for this beacon channel is automatically saved in EEPROM memory, in particular the country code MCCE and the code MNCE from

foreign network RRE.

  According to a first variant, step S3 reads the MCCE code of the country in the location area identity LAI recorded in the EEPROM memory

during the last zone transfer.

  According to a second variant, the EEPROM memory of the SIM card recorded beforehand during the subscription a list of MNCE callsigns of foreign RRE radiotelephone networks with the names of the corresponding countries, networks whose operators have for example contracted cooperation agreements with the operator of the original network RRN0. In this case, the subscriber selects on the screen the foreign RRE network of the country in which he is located. Step S3 then reads the code MCCE of the country over which the selected foreign network extends and the code MNCE of the selected foreign network, so that the terminal MS '

  selects a traffic channel for this network.

  In the next step S4, the country code of origin MCC0, or the country code of residence in the specific field, read in step S2 is compared with the country code "foreign" MCCE contained in the location zone identity LAI or selected in the network table. If MCCO = MCCE, the subscriber is still in his country of origin, or in his country of residence. The number called NA = 0 NN can be used and remains unchanged; it is inserted in the SET UP establishment message in step S5, like 18a 2788190 in step E6 according to the prior art (FIG. 2). If in step S4, MCC0 is different from MCCE, the subscriber is outside his country of origin, or his country of residence. The national called number NA = 0 NN can no longer be used and is changed to a significant international number in the following steps S6 to S9 so that it is acceptable by all

foreign network.

  In step S6, the TON field initially at 0 for the open format changes to 1 for the international format. According to another variant, the TON field can for example be set to 1 before step E4, and toggled to 0 only when performing step E6 'or S5. Then in step S7, the long distance prefix 0 is removed from the called number NA which becomes the significant national number NN. In the next step S8, the code of the country of origin or of residence CC0 is read in correspondence with the country code MCC0 in a table of the EEPROM memory previously recorded which matches the foreign country codes MCC0, MCCE with country codes CC0, CCE, respectively, or is read in a specific field of the EEPROM memory. The CC0 country code thus read is added to the top of the national number NN. The number called CC0 NN with the field TON = 1 is inserted in the SET UP establishment message in step S9, as in step E9. Finally, the establishment message is sent to the MSCE switch temporarily attached to the

terminal MS 'in step EF.

  Optionally, the invention provides in step S9 to add to the significant international number CC0 NN the international code + and to write the called number + CC0 NN in the memory directory

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  EEPROM of the SIM card instead of the initial number 0 NN. In this case, as and when the numbers called from the country of origin or residence are used by the subscriber abroad, these numbers will be stored in international format and will be processed

  quickly through steps E7, E8 and E9.

  According to a simpler embodiment, when a number called NA in open format in the form NA = OI AB PQ MCDU is to be dialed using the keyboard or by voice recognition in the terminal MS, whether the terminal is in the country of origin or of residence or that it is abroad, the number called NA being dialed is converted to the international format + CC0 I AB PQ MCDU. In this case, step S7 to remove the long distance prefix 0, step S8 to add the country of origin or residence code CC0 and the supplement to step S9 to write the number called at international format + CC0 NN, are carried over to step E2 before completely writing the called number converted to international format in the EEPROM memory of the SIM card

  of the mobile radiotelephone terminal.

  Likewise, when the called number being dialed is an international number, but in open format, starting with the international prefix 00, this prefix is replaced by the international code + before the called number is completely written in

  the terminal's SIM card EEPROM memory.

  In this simple embodiment, the method of FIG. 3 comprises the succession of steps S7, S8 and the complement of step S9 corresponding to the writing in step E2, the validation and reading of step E4, and steps E7, E8 and E9 when the

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  dialed number is a national number starting with the long distance prefix O.

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Claims (15)

  1 - Dialing method in a radiotelephone terminal, characterized by the following step when a called number (NA) is not an international number: - add (S8) a code (CC0) of country of origin   at the beginning of the called number (DN).   2 - Method according to claim 1 comprising the following steps when a called number (NA) is not an international number: compare (S4) a country code of origin (MCC0) with a code (MCCE) of the country where the terminal is located (MS), - do not modify (S5) the called number (NA = 0 NN) when the country codes compared are identical, and - carry out the said step of adding when the   country codes compared are different.   3- A method according to claim 2, comprising a reading (S2) of the country code of origin (MCC0) in a subscriber identity (IMSI) stored in the terminal (MS).   4 - Process according to claim 2, comprising a reading (S2) of the country code of origin (MCC0) in a specific field of a terminal memory (EEPROM) (MS).   - Process according to any one of   claims 2 to 4, comprising a reading (S3) of   the code (MCCE) of the country where the terminal is located 22 2788190   in a location area identity (LAI) stored in the terminal (MS).   6 - Process according to any one of   claims 2 to 4, comprising the following steps   before the step of comparing (S4): - select (S3) a radiotelephone network (RRE) of the country where the terminal is located (MS) in a network table stored in the terminal, and - read (SB) the code (MCCE) of the country where the terminal is located in the correspondence table with the selected network.   7 - Process according to any one of   Claims 1 to 6, comprising a withdrawal (S7) from a   long distance prefix to the called number (DN) before the add step (S8).   8 - Process according to any one of   Claims 2 to 6, comprising a withdrawal (S7) from a   long distance prefix of the called number (NA) before the add step (S8) when the country codes   compared (MCC0, MCCE) are different.   9 - Process according to any one of   claims 1 to 8, comprising a reading (S8) of   country of origin code (CC0) in a specific field   a memory (EEPROM) of the terminal.   10 - Process according to any one of   claims 2 to 6 and 8, including a reading   (S8) of the code (CC0) of the country of origin in correspondence with the code (MCC0) of the country of origin in a country table stored in the terminal. 23 2788 190   11 - Process according to any one of   Claims 2 to 6, 8 and 10, including a setting   from a number type field (TON) to an international format state when the country codes   compared (MCC0, MCCE) are different.   12 - Process according to any one of   claims 1, 7 and 9, according to which the step   adding (S8) precedes a writing (E2) of the called number (NA) in a memory (EEPROM) of the terminal (MS). 13 - Process according to any one of   claims 2 to 6, 8, 10 and 11, according to which   the step of comparing (S4) follows a reading (E4) of the called number (NA) in a memory (EEPROM) of the terminal (MS).   14 - Process according to any one of   claims 1 to 13, comprising after step   to add (S8), a step of adding (S9) an international code (+) to the beginning of the called number in order to write it as an international number in a memory (EEPROM) of the terminal.   - Process according to any one of   claims 1 to 14, according to which when a number   called (NA) is a number preceded by a prefix (00) or international code (+), it is removed (E6 ", E8) of the called number.   16 - Method according to claim 15, comprising setting a number type field (TON) to an international format state when the 24 2788 190   called number (NA) is a number preceded by a   prefix (00) or an international code (+).   17 - Radiotelephone Terminal (MS) comprising an algorithm in memory for the implementation of the method according to any one of the claims 1 to 16.   18 - Subscriber identity module (SIM) insertable into a radiotelephone terminal (MS), comprising an algorithm in memory for the implementation of the method according to any one of the claims 1 to 16.