The Italian NREN GARR successfully performed a Coherent Alien Waves field test over its Dispersion Compensating Module (DCM) - compensated optical transmission infrastructure. This activity was aimed at evaluating the coexistence of 10 Gbps IM-DD channels with high throughput Coherent Alien Wavelengths. The goal of this trial was to verify a possible evolution path from GARR legacy DWDM system towards its new High Capacity Coherent Technology. The stability of the solution was demonstrated both on a 350-km link and over a path that was more than 1100 km long. The results are positive and encourage GARR to consider the Alien Waves Technique a valid solution to deliver high capacity services all across its network. The test results and details will be presented during TNC2016.