2 wires

It is often said that DCC can be run with just 2 wires. Now technically that is true if you have a simple circuit of track. The reality is significantly different. The recommendation is that you have droppers to each individual piece of track to minimise voltage drop. Therefore if your circuit contains just 4 pieces of track then you are immediately up to 8 wires. That is before you think about any accessories.

Here is the block diagram for the new layout.

It's really simple - honest! The pieces are:

1. NCE PH-Pro - the main controller of the layout. This is the heart of DCC. 
2. The handset (T shaped piece bottom left)
3. Programming track (prog) for programming engines
4. Track - which gets broken down into 3 districts each with their own short circuit protection
5. UTP panel - central point for connecting the cab bus
6. NCE AIU - auxiliary input unit for taking in random inputs - there will be 2 of these
7. DBD22 - detects occupancy of a section of track - there will either be 3 or 6 of these
8. Lenz LS150 - point controllers, there will be 2 of these
9. Computer - any old laptop that can run JMRI
10. USB to Serial converter - most DCC systems have serial connectors. Most laptops don't :-(

I can't be truly definitive as to how many wires there will be as the goods yard has not been designed yet. However, my initial calculation is that I will have over 200 wires to put on this layout.

If that wasn't bad enough I've worked out I need 3 different power supplies!