说明：  Informatics and data processing dictionaries define an interface as a common boundary shared by two systems, devices, or programs, as well as the elements of this connecting boundary and the auxiliary control circuits used for linking devices. This book deals mainly with interfaces that allow various peripheral devices and their controllers to be connected to personal (and not only personal) computers. Before starting a detailed discussion of specific PC interfaces, a series of general issues regarding the establishment of connections need to be considered.