This part of ISO/IEC 11518 specifies a control for physical layer switches using the High- Performance Parallel Interface (HIPPI), a high-performance point-to-point interface between data-processing equipment. This part of ISO/IEC 11518 does not protect against errors introduced by intermediate devices interconnecting multiple HIPPI-PHs. The purpose of this part of ISO/IEC 11518 is to facilitate the development and use of the HIPPI in computer systems by providing common physical switch control. It provides switch control structures for physical layer switches interconnecting computers, high-performance display systems, and high-performance, intelligent block-transfer peripherals. This part of ISO/IEC 11518 also applies to point-to-point HIPPI topologies.