Boundary Scan is a testing method used in electronics to check the integrity of connections on a printed circuit board (PCB). It involves adding special circuitry, known as Boundary Scan cells, to the chips on the board. This allows for testing signals at the pins of the chips without needing physical access to them, making it easier to identify faults. The IEEE 1149.1 standard defines the Boundary Scan technique, enabling manufacturers to perform tests during production and after assembly. This method helps ensure that the components are correctly connected and functioning, ultimately improving the reliability of electronic devices.