The IEC 61850 standard originally was developed for the substation automation. During the past years it was adapted for the integration of distributed energy resources into communication networks, however, with specific requirements. Many small and midsize manufacturers are using, as controllers, a big variety of different microprocessors with limited performances. Such controllers need an interface for IEC 61850 communication networks with a basic functionality which can be implemented with limited costs. Based on their experiences during the realization of an IEC 61850 communication stack, the authors propose ways to support these requirements. In particular, communication interfaces for photovoltaics systems and wind power plants are considered.