The goal of IDM is to communicate devices that use different technologies. One of this network technology is RS-485, but it does not specify the means to send messages from any device on any time. This protocol tries to solve the problem.
Any RS-485 network has multiple devices using a master-slave paradigm (or in the RS-485 nomenclature, driver-reader). Only the driver can write on the bus, and all readers can read. Every node could became a driver, but there should be just one driver on the network at a given time.
RS-485 only describes the most low level layer, giving the network layer to be part of the application protocol. In this case, we have designed a protocol called Round Robin Protocol (RRP).