The typical five-step cyclical process of precision agriculture includes soil and environment data collection, diagnosis, data analysis, precision field correction operation and evaluations. Usually, some steps are executed in field, others in the farm office and others in both. This can result in a complex system and consequently in waste of time and high cost in equipment, tools and workmanship. To simplify this process, the challenge is running the whole precision agricultural cycle in computers embedded in agricultural machines, working with different communication technologies, such as wireless sensor network (WSN), in special Zigbee standard, and the agricultural machine bus, ISOBUS (ISO11783) inter-connected. This work considers an inter-connection model between these networks. The model considered is tested in a simulator that has been developed specially for this job and the results are presented herein. On the other hand, the results show that an efficient inter-connection is not possible with common devices such as gateways or converters. It is necessary to develop a new concept for these networks and a possible complementation to the Zigbee or ISOBUS standards. With an efficient inter-connection, it will be possible for the agricultural machines to move through the crop, at the same time that they can scan the soil and the environment and make the necessary corrections, reducing time, costs and workmanship.