The building of the hydroelectric complex at Capdella was undertaken simultaneously from a number of different working areas (the lakes, the water conduits, the site of the power station itself...). From one point to another there were often many kilometres, and efficient communication among the engineers, foremen and workers engaged in these tasks was essential.
In this the field telephone was a valuable tool. The device itself was kept inside a wooden box that hung from a strap so that it could be carried from place to place. It had an earpiece and a handle that had to be turned in order for the connection to be made and communication established.