Test
IPC-D-356
In plain English
A standard connection list that lets a testing machine check a blank board is wired correctly — like an answer key any tester, from any brand, knows how to read.
The technical version
IPC-D-356 (and the revised D-356A) is a standardized netlist format that describes each net's pads, vias, and access points for bare-board electrical test. It is extracted from the copper image in CAM and drives flying-probe or bed-of-nails testers. It lets fabricators verify connectivity independent of the original design tool.