See the wiring guide for a detailed introduction of the main connections.
The version 1.0 and later boards is shown in the diagram below.
Click on the file for a larger version
(There is an error on v1.0 and v1.01 on the silkscreen where the E0-/E1- and VIN are reversed - use the diagram above rather than the silkscreen. This is fixed in v1.02 boards)
For the initial beta testers who have the old WHITE prototype 2 boards the pin out is below. the differences from the production boards are:
a)probe connector reversed.
b)SD and LCD connectors reversed.
c)endstop connectors reversed.
If you are looking for the Duex2/5 wiring diagrams see this page: Duex Wiring Diagrams