The Picaxe "SerialPower" Network combines power delivery and bi-directional communications between processes on intelligent, picaxe-based battery-less nodes. This can be implemented using just two interchangeable wires. Simple diode-mixing networks with separate power and communication wires are supported as well.
A master node provides for power as well as "timeslots" during which processes on nodes can exchange messages with each other using a standard format. The slave nodes are powered from the network and only need a backup capacitor. Both master and slave nodes can be implemented using any available Picaxe type.
A separate website with all the information required to implement applications can be found here: SerialPower Website. The discussions on the Picaxe Forum can be found here: SerialPower on Picaxe Forum