A method for using telephone book data stored in data sets (DS, DS1, DS2, DS3) in a telephone book database of a server by a telephone comprising the following steps: (a) the telephone connected to a packet-switched network and/or to a circuit-switched network is physically connected to the telephone book database via the server; (b) the telephone initiates by means of a first event (Fig. 3), incoming telephone call with call number transmission, which triggers the access to the telephone book database, a targeted telephone book search with respect to the search result and/or by means of a second event (Fig. 4), menu call "telephone book search" by a telephone user, which triggers the access to the telephone book database, an open telephone book search in the telephone book database with respect to the search result; (c) with the start of the telephone book search the telephone establishes a logical connection to the server comprising the telephone book database and transmits according to a dedicated protocol directly or indirectly after login or authentication at the server or at the telephone book database at least one search criterion for the telephone book search to the server; (d) the server after confirmation of the login or verification of the authentication optionally carries out the search in the telephone book database based on the search criterion/search criteria and transmits the search result to the telephone according to the protocol, wherein the search result includes data sets stored in the telephone book database, wherein each of these data sets has a data set structure specified by marks of the dedicated protocol, wherein the marks indicate the respective data type of the data included in the data set, such as last name, first name, location, street, country, postal code, fax number, industry, special branch, email address or call number, such that the telephone is able to understand the semantics of the search result and thus uses the individual data in the respective data set independently from each other for telephone-specific operations, such as an outgoing telephone call or Calling Line Identification Presentation, wherein a DECT handset of a DECT telephone comprising a DECT base station which is connected to the packet-switched network and/or the circuit-switched network is used as the telephone, or a WLAN handset of a WLAN telephone with a "WLAN access point" which is connected to the packet-switched network and/or the circuit-switched network is used as the telephone, or a telephone handset which is connected to a "router" which is connected to the packet-switched network and/or the circuit-switched network is used as the telephone; and (e) the search result is displayed on a telephone display of the DECT handset, the WLAN handset or the telephone handset. (a) the telephone connected to a packet-switched network and/or to a circuit-switched network is physically connected to the telephone book database via the server; (b) the telephone initiates by means of a first event (Fig. 3), incoming telephone call with call number transmission, which triggers the access to the telephone book database, a targeted telephone book search with respect to the search result and/or by means of a second event (Fig. 4), menu call "telephone book search" by a telephone user, which triggers the access to the telephone book database, an open telephone book search in the telephone book database with respect to the search result; (c) with the start of the telephone book search the telephone establishes a logical connection to the server comprising the telephone book database and transmits according to a dedicated protocol directly or indirectly after login or authentication at the server or at the telephone book database at least one search criterion for the telephone book search to the server; (d) the server after confirmation of the login or verification of the authentication optionally carries out the search in the telephone book database based on the search criterion/search criteria and transmits the search result to the telephone according to the protocol, wherein the search result includes data sets stored in the telephone book database, wherein each of these data sets has a data set structure specified by marks of the dedicated protocol, wherein the marks indicate the respective data type of the data included in the data set, such as last name, first name, location, street, country, postal code, fax number, industry, special branch, email address or call number, such that the telephone is able to understand the semantics of the search result and thus uses the individual data in the respective data set independently from each other for telephone-specific operations, such as an outgoing telephone call or Calling Line Identification Presentation, wherein a DECT handset of a DECT telephone comprising a DECT base station which is connected to the packet-switched network and/or the circuit-switched network is used as the telephone, or a WLAN handset of a WLAN telephone with a "WLAN access point" which is connected to the packet-switched network and/or the circuit-switched network is used as the telephone, or a telephone handset which is connected to a "router" which is connected to the packet-switched network and/or the circuit-switched network is used as the telephone; and (e) the search result is displayed on a telephone display of the DECT handset, the WLAN handset or the telephone handset.