Abstract: A testing apparatus and method consisting of multiple measurement modules having one or more circuit assembly boards, two data/power connectors, and a target connector. Signal data is accessed from 1-128 target signal sources and sampled through two separate analog to digital channels. An on-board microcontroller controls signal selection and data sampling rates and also provides for transfer of recorded data over a USB bus to a host computing device. Using a proper testing application loaded onto the host computing device, each module can be commanded to access and store representative data from a number of signal sources at each target system. Each module is connected to other modules and a host computing device to create a complete self-powered test access environment. The interconnectivity of the system makes diagnosing electronic component failures in an armored vehicle, such as a tank, much easier than prior manual fault isolation procedures.