Generally, who should respond to a station in the contiguous 48 states calling “CQ DX”?

In amateur radio terminology, "DX" stands for distance. For a station located in the contiguous 48 US states, a call of "CQ DX" is a specific invitation for stations outside of the contiguous 48 states to reply. This includes foreign countries as well as Alaska, Hawaii, and US territories. Standard operating etiquette dictates that you should only respond to a directed CQ if you match the requested criteria. If a station in the same country or region replies to a CQ DX call, they are causing interference and disrupting the calling station's goal of making international or long-distance contacts. While any caller might hear the signal, it is considered poor practice for another station within the lower 48 states to answer.