A model appropriate for computer simulation of a high-temperature superconducting detector's responses to microwaves and visible light has been developed at the Applied Physics Laboratory. This model will be used to approximate the responses of a bismuth-strontium-calcium-copper oxide detector to microwave frequency and helium-neon laser light over a wide temperature range (from zero up to the critical transition temperature of the superconductor) on the basis of microscopic theoretical results. The nonbolometric (microwave) detection mode is emphasized here because it is faster and more sensitive than the bolometric (helium-neon) mode, which is already well understood.