A method of operating a self service terminal (SST) (12) is described, in which the SST (12) detects characteristics of a mobile computing device held by a user (16), and configures the user interface dependent on the detected characteristics. The characteristics may include features of the mobile device, such as communication facilities, or may include user identification information. Where the user is identified, a user profile may be retrieved from a remote SST operator (14). Certain embodiments of the invention may detect devices held by a second or subsequent user (18), and retrieve the relevant user profile prior to the second user (18) interacting with the SST (12).