68-Pin VHDCI Male to 68-Pin VHDCI Male, 50 Ω, Unshielded Digital Cable—The C68-C68-D4 connects NI-6535/6/7, NI-654x, NI-655x, and NI-657x digital instruments with other NI accessories like the CB-2162 Connector Block or SMB-2163 Terminal Block. You also can use this cable with certain Digital I/O Adapter Modules for FlexRIO, Digitizer Adapter Modules for FlexRIO, Signal Generator Adapter Modules for FlexRIO, and high-speed serial instruments. Additionally, the C68-C68-D4 features flexibility suitable for custom test fixtures and other equipment.