Industry standards such as Ethernet and USB help ensure the interoperability of the computers, peripherals, and networks we depend on every day. Compliance testing is essential because any level of incompatibility can be costly in time and money for vendors and end-users. Here’s a big surprise: if you peruse the compliance criteria, plug-and-play may be less robust than we might imagine. The underlying issue is the cascade of incompatibility percentages. When the interoperability numbers from connected devices are multiplied, the result is low enough to introduce significant risk. This is especially true for automated test systems.