The good news is that installation is simple and inexpensive.1) only a single 5 mm Dia. cable from one helm to the processor, in or near one engine room is needed. All data to control both engines is carried on this single cable. The processor is commanded by any helm unit to carry out a myriad of functions to both engines. (See diagram below)2) Up to three helm units and one remote (or 4 helm units) can be used. All units are wired in parallel. (See diagram)