The Boundary-Scan Test allows to test electronic boards even if there is reduced access to the printed circuit board.
In a very simple case, the BST of a board may be performed via plug connectors.
Digital components require an JTAG port.
Compared to ICT, the BST needs longer test periods and testing analogous components is not possible.
The BST ideally supplements the ICT to be able to test parts of a circuit which cannot be contacted.