When communications intelligence identifies a particular radio transmitter as the one used only by a particular country, detecting that transmitter inside one's own country suggests the presence of a spy that counterintelligence should target, therefore CI refers to efforts made by intelligence organizations to prevent hostile or enemy intelligence organizations from successfully gathering and collecting intelligence against them.
For example, when communications intelligence identifies a particular radio transmitter as one used only by a particular country, detecting that transmitter inside one's own country suggests the presence of a spy that counterintelligence should target. CI refers to efforts made by intelligence organizations to prevent hostile or enemy intelligence organizations from successfully gathering and collecting intelligence against them. 
