The present invention relates to a method of operating a radio communications network with a plurality of mobile communications equipment using subscriber numbers which are stored in each of the mobile communications equipment, the method comprising a step of transmitting, on the basis of the subscriber numbers of the mobile communications equipment, a connection address to a database. It is a particular object of the present invention to provide a method of the kind referred to above, wherein a subscriber number of a subscriber of a mobile communications equipment can be stored. In order to perform such subscriber number storage, it is customary that subscribers wishing to save their subscriber number (which is assigned by the operator of the network, typically by subscription with the operator) can save them by means of their mobile station and the communication interface for that subscriber number to the network must be known to the respective system. For example, a German Patent DE 26 11 690 A1 proposes to provide mobile stations which have no own SIM cards with a special SIM card which may be used in another mobile station. In the method proposed in the German Patent DE 26 11 690 A1, only the subscriber number assigned to the SIM card can be utilized by the mobile station. The method is proposed for subscribers who want to keep their operator number while also utilising a mobile station which is rented and which may also be used by many different operators. The German Patent DE 26 11 690 A1 proposes to store the subscriber number of the SIM card in a special storage place in the mobile station, thus allowing the mobile station to be used in a mobile station of another mobile station manufacturer. A German Patent Application DE 198 18 852 discloses a method for providing the subscriber number stored in a SIM card of a mobile station with a priority in order that this mobile station can be used as the network origin. This mobile station or mobile station apparatus is then called the master mobile station. All further mobile stations are connected to the master mobile station as slave mobile stations. The master mobile station is equipped with a master data function. When the master mobile station is connected to a base station, the master data function transmits, in response to an information about the mobile station of the slave mobile stations to be detected, at least one service signal that belongs to the service of the master mobile station to the slave mobile stations. According to the DE 198 18 852, all service signals are to be transmitted when the master mobile station detects the existence of one or more slave mobile stations. When the master mobile station is connected to a base station, the service signals in this embodiment are determined from subscriber number data stored in the SIM card. A German Patent DE 42 18 735 discloses a method of determining, from different subscriber numbers or identities, a common reference number that can be used for communications between the different subscribers. In connection with this Reference number, it is possible to obtain a common reference number for one or more mobile station. This method relates to the usage of one single mobile station. The reference number is stored in the SIM card of the mobile station, which can be easily read by a network server for processing. Although this method is intended to enable mobile station reuse in different networks, it has a number of disadvantages. Firstly, the different mobile stations have to share the same reference number, which has to be stored as a single piece of information in each mobile station. As a result, each mobile station must be issued a different SIM card number. A unique subscription number or personal identity module number (PIN) cannot be allocated to the reference number as this reference number is intended to be used for subscribers who share a mobile station. Secondly, the mobile station or the mobile station apparatus must provide support for the use of a different reference number or PIN, if several different SIM cards are provided. If no mobile station is provided with more than one SIM card, then this solution is impossible. There is a need for a method that permits the above-mentioned subscriber number storage with an arbitrary number of mobile communications equipment. There is also a need for a method which enables the reference number to be reused by any mobile station of a plurality of mobile communications equipment. The present invention provides a method of operating a radio communications network with a plurality of mobile communications equipment using subscriber numbers, wherein a subscriber number of a subscriber of a mobile communications equipment can be stored, the method comprising a step of transmitting, on the basis of the subscriber numbers of the mobile communications equipment, a connection address to a database, wherein the step of transmitting is carried out in accordance with a pre-assigned subscriber number, whereby each of the plurality of mobile communications equipment is assigned a different subscriber number. By pre-assigned, it is to be understood that this means that each mobile station is assigned a specific individual subscriber number. Although the plurality of mobile communications equipment is used in the same network, each mobile station is provided with a separate customer number for addressing the network. No limitation of this embodiment to use in the same network is set as a pre-condition, although such a limitation is obvious to those skilled in the art. The connection address is preferably sent in the IMSI character of the mobile station. For example, if the IMSI character contains xe2x80x9c3xe2x80x9d, then this denotes that the subscriber number of the mobile station is stored. In the network, a mobile equipment identifier, which is sent on the basis of the IMSI, is the basis for assigning the subscriber number. As a result, it is not necessary to store the subscriber numbers of the mobile communications equipment as such in a database. The subscriber number can be transmitted as a connection address. The subscriber number is stored at least in the mobile communications equipment. If an operator identifies that it desires to use the network as a provider of a mobile communications service for third parties, then it would be sufficient to store only a customer number of the third party as a subscriber number. The reference number (for example IMSI) of the network is stored as an address which can be used to address the third party. The connection address of the third party can be stored, with the connection address containing the customer number. However, in that case, the identifier used to receive the connection address would contain the IMSI. The connection address is preferably stored in a mobile switching center of a communication system. However, the connection address can also be stored in a base station. The present invention also provides a method for providing the subscriber number stored in a mobile communications equipment to a communication system, comprising the steps of storing the subscriber number in a database of a mobile switching center, setting up a connection with a communication system, wherein the connection is based on a connection address of the mobile switching center and wherein the connection address includes the subscriber number, and storing the connection address. The present invention also provides a method of providing the subscriber number stored in a database of a communication system to a mobile communications equipment, comprising the steps of setting up a connection with a communication system, wherein the connection is based on a connection address of the communication system, and storing the connection address. The present invention also provides a method of providing the subscriber number stored in a mobile communications equipment to a communication system, comprising the steps of storing the subscriber number in a database of a mobile switching center, setting up a connection with a mobile communications equipment, wherein the connection is based on a connection address of the mobile switching center, and storing the connection address. It is to be understood that each of the communication systems, mobile switching center, mobile communications equipment, databases and communication is provided for example in a GSM system. Preferably, the communication system is a mobile telephone network. In that case, the communication system is preferably a GSM mobile telephone network. However, it should be noted that the communication system can be any type of mobile network which includes at least one mobile switching center and at least one database and is capable of transmitting and receiving information from the database. The mobile communications equipment may be a GSM mobile telephone, a PCS mobile telephone, a mobile station adapted for communicating using the FLEX mobile telephone system, or a mobile station adapted for communicating using the DECT system. The subscriber number is preferably stored in the mobile station. However, it is also possible that the subscriber number is stored in a subscriber""s phone book. In a mobile communications system of a predetermined type, it is possible to provide a subscriber number stored in the mobile communications equipment by using a connection address of the mobile communications equipment stored in a communication system, in order to establish a connection to that communication system. This communication system may be the above-described network or the same as the above-described network, such as GSM. In that case, the stored subscriber number can be accessed in the mobile communications equipment. For example, the mobile communications equipment may comprise a subscriber number stored in the mobile communications equipment and a stored connection address of the network. However, in that case, it is not possible to enter a subscriber number, for example, by means of a user key or a menu. A connection must be established to the network by using the connection address of the mobile communications equipment, for example the IMSI. In the case of a call request of the subscriber number, the connection is set up with the network, for example GSM mobile telephone network. The connection address is then transmitted from the mobile communications equipment to the communication system and is stored in a database of the communication system. In this way, it is possible to receive the connection address of the mobile communications equipment in the communication system and, as a result, provide the subscriber number stored in the mobile communications equipment.