Several European projects on smart grids are considering Electric Vehicles (EVs) as active element in future power systems. Both battery-powered vehicles and plug-in hybrid vehicles are expected to interact with the grid, sharing their energy storage capacity. Different coordination concepts for EVs are being investigated, in which vehicles can be intelligently charged or discharged feeding power back to the grid in vehicle-to-grid mode (V2G). To respond to such needs, EVs are required to share their battery internal data as well as respond to external control signals. In this paper, the requirements for the interaction of EVs with the electrical grid are presented. The defined requirements have been implemented on an EV test bed, realized by using real EV components. Charging/V2G tests on the EV test bed have shown that the presented requirements are sufficient to ensure an intelligent coordination of EVs into the electricity grid.