Unlike other two-wire systems, the Irritrol® Rain Master Twice 2-wire protocol provides a two-way communication link between the controller, decoders and valves. This provides the means for testing and diagnostic capabilities within the 2-wire system. The simplicity of the 2-wire field installation, coupled with the enhanced capability of the Rain Master ‘E’ series controllers, sets a new precedent for 2-wire control within the irrigation industry.