Hard Metric, StandardHard metric and standard backplane connectors are two different types of connectors that are used in backplane applications. A backplane is a printed circuit board (PCB) that is used to connect and distribute signals and power between different components in an electronic system. Hard metric backplane connectors are designed to comply with the IEC 61076-4-101 standard, which defines the dimensions and performance specifications for these connectors. They are characterized by their high-density pin arrangements, which allow them to carry a large number of signals in a small space. Standard backplane connectors, on the other hand, are not designed to comply with any specific standard, and may vary in their dimensions, pin arrangements, and performance characteristics. Standard backplane connectors are commonly used in a wide range of electronic systems, including computers, telecommunications equipment, and industrial control systems.