A computer system for processing interferometric synthetic aperture radar images includes a database for storing SAR images to be processed, and a processor for processing interferometric SAR images from the database. A buried semiconductor layer of a second conductivity type is provided on the substrate. An electroacoustical transducer connected to the first plug and the second plug is operative for converting a first electric signal transmitted via the first plug into corresponding sound, and for converting a second electric signal transmitted via the second plug into corresponding sound. The setup message can indicate whether substitution for a link is permitted.