The Hemisphere External Radio Cable amalgamates into one all the cables needed to connect your external power to your receiver. The cable contains a 5 Pin power port for sending out corrections and receiving power. The cable also comes with a 5-Pin radio port that is compatible with both the Harxon radios and Pacific Crest ADL radios. Power is provided through the trailer plug, and is capable of powering both the external radio and the Hemisphere S631 receiver at the same time. As in older makes, multiple cables were required for the receivers to function. But you get a 3-in-1 with the Hemisphere External Radio Cable, thus eliminating the nonessential.