In this paper we introduce a model for direct communication in situated multi-agent systems. Direct communication is typically associated with cognitive agents, where the information encoded in the messages is related to a mental state. This generally assumed view on communication however, does not fit the approach of situated, behavior-based agents. We propose a protocol-based communication model for situated agents. Communication specified in terms of protocols, i.e. well-defined sequences of messages, shifts the focus of communication from the reasoning upon messages towards the relationship between the exchanged messages. The model decomposes communication into three functional modules: message decoding, communicating and message encoding. The core of the model, the communicating module (1) interprets decoded messages and reacts to them in accordance with the applicable protocol, and (2) initiates or continues conversations when the conditions imposed by the applicable protocol are satisfied.