The present invention provides a system, method and apparatus for improved electrical-to-optical transmitters disposed within printed circuit boards. All of the system components may be contained in a portable bag about four feet long. The local oscillator is configured to generate a laser signal to indicate a selection of one of a plurality of channels. The power plant coolant circuit includes a heater core branch having a HVAC pump, a coolant heater, a heater core located in a HVAC module to provide heat to the passenger compartment, and the coolant-to-coolant heat exchanger, with the coolant-to-coolant heat exchanger providing heat transfer between the coolant in the coolant heating branch and the coolant in the heater core branch.