Abstract: The down-hole instrument cable includes a hermetically sealed optical fiber surrounded by a protective buffer layer and a protective gel within a protective tube. A layer of electrical conductors between an inner insulator and outer insulator layer surrounds the protective tube, and electrically conductive strength member strands surround the outer insulator layer. The cable includes an electrically conductive cable head body electrically connected to the strength member strands, and an electrically conductive contact subassembly, through which the optical fiber and electrical conductors extend. The contact subassembly provides a first electrical terminal for connection to the down-hole instrument, the layer of electrical conductors provides a second electrical terminal, and the optical fiber provides an optical signal pathway for the down-hole instrument.