The DCU-2000 (PCU-2000) product supplied as part of DCI-5000 systems is now in the Limited phase of its life cycle where it is not actively sold. It has been superseded by other controller and I/O offerings. The most recent of these is the Harmony DCU with S800/S900 I/O product. Existing PCU-2000 configurations can be converted to run on the newer controllers thereby preserving the users intellectual investment. In addition, terminal connection adapters are available to preserve the users field wiring thereby simplifying and cost reducing the migration to the newer controller and I/O. Use of these newer controller and I/O products requires other system upgrades to the operator interfaces and networks. ABB can provide cost effective migration solutions through conversion services and StepUp programs.