Method for operating a DSL (digital subscriber line) in a telecommunications network, wherein the DSL is provided between a network-side access node device and a subscriber-side connection device for transfer of user data and signalling information, wherein the access node device, the connection device and the DSL can be operated alternatively in a first operating mode or in a second operating mode or in a third operating mode, wherein, in the first operating mode, the access node device, the connection device and the DSL comprise a preset first data transfer rate, wherein, in the second operating mode, the access node device, the connection device and the DSL comprise a preset second reduced data transfer rate, wherein, in the third operating mode, the access node device, the connection device and the DSL are at least partially switched off, wherein the setting of the first operating mode in the absence of a momentarily present data transfer requirement of an increased data transfer rate is provided for the case where - the access node device and the connection device and the DSL are in the second operating mode and - the access node device and/or the connection device receives an item of signalling information for establishing a preset data connection requiring a data transfer requirement with an increased data transfer rate, wherein the setting of the first or second operating mode in the absence of a momentarily present data transfer requirement of an increased data transfer rate is provided for the case where - the access node device, the connection device and the DSL are in the third operating mode and - the access node device and/or the connection device receives an item of signalling information for establishing a preset data connection requiring a data transfer requirement with an increased data transfer rate, wherein the connection device comprises a first detector unit or the connection device is allocated a first detector unit, wherein the access node device comprises a second detector unit or the access node device is allocated a second detector unit, wherein the first detector unit and/or the second detector unit use a comparison of the received signalling information with an item of predetermined reference information to detect whether a data transfer requirement of an increased data transfer rate is expected, wherein the preset data connection is a subscriber side-initiated data connection and is detected by means of the first detector unit and/or wherein the preset data connection is a subscriber side-terminated data connection and is detected by means of the second detector unit. - the access node device and the connection device and the DSL are in the second operating mode and - the access node device and/or the connection device receives an item of signalling information for establishing a preset data connection requiring a data transfer requirement with an increased data transfer rate, - the access node device, the connection device and the DSL are in the third operating mode and - the access node device and/or the connection device receives an item of signalling information for establishing a preset data connection requiring a data transfer requirement with an increased data transfer rate,