Pure-reference catalog of hardware-in-the-loop (HIL) testing for embedded systems. Defines the HIL pattern (ECU-under-test + real-time plant simulator + I/O cards emulating sensors / actuators / buses), the V-cycle progression (MIL → SIL → PIL → HIL), the canonical vendor stack (NI VeriStand + PXI / CompactRIO, dSPACE SCALEXIO / MicroAutoBox, Vector CANoe + VT System, Speedgoat real-time targets), bus emulation per protocol (CAN / CAN FD / LIN / FlexRay / Automotive Ethernet / SOME-IP), fault-injection patterns (short-to-ground, open-circuit, signal corruption), DO-178C / ISO 26262 / IEC 61508 alignment, and the test-evidence chain HIL produces. Use as the HIL terminology + vendor + standard reference when scoping an embedded test rig or interpreting an automotive / aerospace / industrial HIL test report.