The origins of JTAG are inextricably bound up with boundary scan. Yet, it provides many capabilities to many purposes. Often, as part of a point tool, whether for debug, programming, test or validation, it takes on just one capability. But, no matter the purpose, as the thread common to all, the standard Test Access Port (TAP) opens the way for many applications. In the test domain, several of these unite under the banner Non-intrusive Board Test (NBT).
