1. A processing device for processing data coming from a contactless memory card, said device comprising at least one contactless memory card reader, said device being connected to or integrated at least partially into a user's personal communications terminal, said device comprising: means for acquiring input data coming from an input peripheral; processing means for processing at least one sequence of a remote transaction initialized on the basis of data coming from a contactless card; selection means for selecting a mode of operation comprising at least two states: state, called an inactivation state, in which said processing means and said at least one memory card reader are inactive and in which pieces of input data entered through said input peripheral are transmitted to the operating system of said communications terminal; and a state, called an activation state, in which said processing means and said at least one memory card reader are active and in which pieces of input data entered through said input peripheral are controlled by said processing means.