On September 9th, the first prototype of a smart submarine cable developed by the Portuguese-American consortium that frames the K2D project was installed in the Sado Estuary. An important milestone of the project was reached with the successful test, in conditions close to real ones, which attest to the validity of the concept. The test had the cooperation of the Portuguese Navy, which provided physical and human resources for the installation of the prototype on the estuary bed. This location was chosen because it is part of the Navy's Technological Free Zone (ZLT) for maritime technology experimentation. The installation was done on September 9th in the morning, to take advantage of the tides, and to date it has been verified that all components and systems have worked correctly, including communication with land.