Patent ID: 8477517

Claim:
A contact-input circuit for high-speed communication among power system devices, for detecting and processing a higher voltage communication signal from a second power system device for use by a lower voltage circuit of a first power system device, the contact-input circuit of the first power system device comprising: a voltage threshold detection device adapted to detect presence of the higher voltage communication signal from the second power system device and to receive the higher voltage communication signal from a contact input; and, an opto-isolator device coupled to the voltage threshold detection device, wherein the voltage threshold detection device conducts current to the contact input, and only when the voltage threshold detection device detects that the higher voltage communication signal from the second power system device reaches a select threshold indicating presence of the higher voltage communication signal, the voltage threshold detection device allows current to flow through the opto-isolator thereby allowing said opto-isolator to provide a voltage signal suitable for use by the lower voltage circuit.