Sfera basic sound module for making 2-wire intercom systems. Equipped with speaker volume and microphone adjustments. Handles up to a maximum of 100 button calls, using additional double row button modules. Allows the activation of an electric lock connected directly to terminals S and S 18 V 4 A pulse 250 mA maintenance on 30 ohm max and the connection of a local door opener button on terminals PL. To be completed with finishing faceplate. The device must be physically configured.