This paper describes a tool called ConData used as test generation for communication protocols specified as extended finite state machines. The strategy for test generation combines different specification-based test methods: (i) transition testing for the control part of a protocol and (ii) syntax and equivalence partitioning for the data part. The tool uses a representation of the protocol in PSL (Protocol Specification Language), which is transformed into a format readable by a Prolog program. This implements the test strategies mentioned above. The text also presents some results obtained in the test generation for the protocol of the Tele-command Communication System of the SACI-1 satellite.84303319