An apparatus for interconnecting a four wire control such as a thermostat and a four wire system such as a heating/cooling system with two wires. An encoder encodes signals provided by the thermostat so that four encoded signals may be transmitted over a two wire system. The apparatus includes inductors...http://www.google.fr/patents/US4889179?utm_source=gb-gplus-shareBrevet US4889179 - Two wire adaptive system for interconnecting a four wire thermostat and a four wire, heating/cooling system
Two wire adaptive system for interconnecting a four wire thermostat and a ...
