The DC Block is used to prevent the flow of direct current or video along a transmission line while permitting the uninterrupted flow of RF. The unit consists of a short length of coaxial line, having a capacitance in series with the center conductor. The RF is transmitted with negligible reflection or attenuation while the DC or video frequencies are blocked. The outline dimensions of the components are the same as for standard connectors and adapters. Special components can be engineered to customer specification.