Abstract: A method for acquiring electronic data and a data medium forming an electronic shopping cart include a processing unit and a data memory connected to a charging device. Preferably, the medium is a smart card. Information relating to a payment operation to be performed in connection with data acquisition is transferred between the processing unit and the charging device, resulting in a payment of a purchase price for the acquired data. The data medium is also connected to an external data memory for storing the acquired data. The data that is to be acquired is transferred from the external data memory to the data medium and is stored in the data memory. Preferably, the memory is integrated and has a capacity of at least 1 MByte. The data medium combines a payment function and the function of a bulk memory for the electronic data that has been acquired.

Abstract: The communications system operates at two distinct operating modes. Each of the slave stations, which are controlled by a master station, has a first output circuit and a second output circuit. The two output circuits are connected to one another on the output side. In a first operating mode, the slave stations are identified by the master station, all the first output circuits can be activated and the system operates at a low clock rate. In a second operating mode, a transfer of data takes place, one of the second output circuits can be activated, and the system operates at a higher clock rate.

Abstract: The operation of any desired number of initially unidentified slave stations in a communications system is possible. An identification procedure with a subsequent address assignment is carried out by a master station M, in that all the slave stations simultaneously output bit by bit, via open-drain output circuits OC, individual identification codes ID which are stored in them.