The 1-Wire protocol is a proprietary protocol (Maxim/Dallas) single-wire interface, half-duplex, bidirectional, low-speed and power, long-distance serial-data communication protocol. It operates over a single data line, without clock signal. But, at least two wires are required for 1-wire bus: Data, GND. An additional wire might be necessary (Vcc), depending on powering mode. The powering modes are: parasitic (no vcc), and conventional (with vcc), as seen on figures below.
