An example system includes a first circuit board having first conductive traces, where a first conductive trace is for conducting an alternating current (AC) digital signal having an edge; a second circuit board having second conductive traces, where a second conductive trace is within a predefined distance of the first conductive trace to produce a contactless coupling with the first conductive trace, and where the contactless coupling enables electrical energy on the first conductive trace to manifest on the second conductive trace as a transient response that is based on the edge; and circuitry to reconstruct the edge based on the transient response from the second conductive trace.