1
Michael D Hollabaugh: Digital two-wire irrigation control system. Clemar Manufacturing Corporation, Fulwider Patton Rieber Lee & Utecht, February 8, 1977: US04007458 (81 worldwide citation)

Apparatus for the control of a number of remotely located irrigation or sprinkler valves from a central location by means of control signals encoded onto a single pair of power transmission lines linking a central encoder and a number of remote decoders. The encoder includes a multiplexer for select ...


2
Michael D Hollabaugh, Vinod Panday: Digital two-wire irrigation control system with feedback. Clemar Manufacturing Corporation, Fulwider Patton Rieber Lee & Utecht, December 26, 1978: US04131882 (80 worldwide citation)

A method and apparatus for the control of a number of valves in an irrigation system utilizing only two lines between a central encoder and a number of remotely located decoders. An alternating-current signal on the lines is used both to transmit power to the decoders and valves, and to convey contr ...