A system comprising first input means for receiving a transport stream from an external source, second input means for receiving an input from a memory, means for connecting the first and second input means to an interface which is arranged to provide an output stream to a decoder. A control system is connected to the stem and arranged to form a partial vacuum in the cup such that the cup is attached to the substrate. The macro expander also expands the second macro to generate appropriate assembler instruction to perform the operation. Each of the first magnetic member and the second magnetic member is made of a magnetic material, and covers a longitudinal-direction end of the magnetic field detector facing the first support.