A method of configuring or changing a configuration of a POS terminal by at least one operator, in which an authorization of the operator by the POS terminal is established, in which after successful authorization of the at least one operator, the at least one operator carries out the configuration or change of the configuration, in which an identification feature for identification of the at least one operator is introduced into the POS terminal, in which this identification feature is used for authorizing the at least one operator. A method of associating a POS terminal with an operator, in which the POS terminal checks the integrity of the identification feature of the operator for identification of the operator, with which the POS terminal is associated.