Here is a general overview of how this is all going to work.

The Software:  It all starts here.  We will have a computer with Vixen(free download) installed on it.  This program is where we will program our "show" into.  It is also responsible for running the show when the hardware is all set up.

The computer wiring:  There are basically 2 connections running from the computer.  The first one is the audio which will run from the computer's sound card to an fm transmitter to broadcast out music selection.  The 2nd connection will connect a cat5e cable to 2 things: the serial port through a RS262-RS485 converter and 12V power supply.  The cat 5 cable carries both the dc voltage and the instruction signal from Vixen.  From the computer, this will be connected to the first controller.  Additional controllers will be connected through cat5 in sequence, i.e. from controller 1 to controller 2, controller 2 to controller 3, etc.

 AC power and lights:  To each controller in the layout, there will be a somewhat heavy duty outdoor extension cord bringing the 120v AC power to the controller from a dedicated GFCI outlet.  This is the power that is actually supplying the lights.  From the controller there will be 16 wires with female plugs(1 for each channel) for the light strands to be connected to.  We will make extension cords to go from these outputs to where the lights are hung.  We'll use regular lamp cord for these extension cords since they will only be carrying 1 amp at most at any given time.

A note about the channels.  Each channel can supply up to about 1 amp safely(without adding heat sinks).  This translates into about 3 strings of lights/channel.  Basically anytime you want to be able to control a set of lights indepentantly, that set will make up a channel.  For example.  Suppose you want to be able to light a wreath with all white lights or all green lights.  The white lights would go on one channel and the green lights will go on another channel.