Single valve control LED indication Unlike other two-wire systems, Rain Master's TWICE protocol provides a two-way communication link between the controller, decoders and valves. This provides the means for testing and diagnostic capabilities within the two-wire path. The simplicity of the two-wire field installation, coupled with the enhanced capability of Rain Master's ‘E' series controllers, sets a new precedent for “Two-Wire“ control within the irrigation industry. The TWICE Two Wire Interface Module; TWICE is compatible with the Sentar II and Eagle / Eagle-i controllers. Two-way communication Decoders insure system integrity between the TWICE module and irrigation valves.