More info here:
http://www.tonick.co.uk/products/adaptor-2wire-decoders-bt2/
This is the translator required to interface any irrigation controller to any 2-wire system.
With this, along with the field decoders that one can buy anywhere, we can make an irrigation system with a single pair of wires, up to 127 stations, with the possibility to be reconfigured or redesigned anytime you want (it only requires to connect a new decoder in parallel with the 2 wires and that’s it).