A system for opening and closing a communication path between two separate environments, said system comprising: • separation means (2, 7) respectively suitable for allowing and preventing, at least partially, the traversing of said path by light, air, or sound waves; • a group (12, 15, 20, 22) for moving said separation means (2, 7) between at least one first open position and one second closed position of said path; said movement group (12, 15, 20, 22) comprising: - a shaft rotatable around an axis and connected to said separation means (2, 7), said connection causing the movement of said separation means (2, 7); - means (12, 20, 22) for rotating said shaft around said axis, - means (18, 19) for commanding said rotation means (12, 15, 20, 22); • a rolling-shutter box for containing said shaft; • a lateral profile for containing said rotation (12, 20, 22) and command (18, 19) means, said rolling-shutter box and said lateral profile being mutually connectable, said shaft and said rotation means (12, 20, 22) being mutually connected when said rolling-shutter box and said lateral profile are mutually connected, said system being characterized in that it comprises means for blocking the rotation of said shaft when said shaft is not connected with said rotation means (12, 20, 22), said blocking means comprising: • at least one first pin (25, 26, 27) that is axially slidable with respect to said shaft but constrained in rotation with said shaft; • a first seat (28, 29, 30) for housing said first pin (25, 26, 27) integrally connected with said rolling-shutter box, said first pin (25, 26, 27) being movable between at least one third position at which said first pin (25, 26, 27) is at least partially housed in said first seat (28, 29, 30), and a fourth position at which said first pin (25, 26, 27) is outside said first seat (28, 29, 30), said first pin (25, 26, 27) being in the third position when said rolling-shutter box and said lateral profile are mutually disconnected. • separation means (2, 7) respectively suitable for allowing and preventing, at least partially, the traversing of said path by light, air, or sound waves; • a group (12, 15, 20, 22) for moving said separation means (2, 7) between at least one first open position and one second closed position of said path; said movement group (12, 15, 20, 22) comprising: - a shaft rotatable around an axis and connected to said separation means (2, 7), said connection causing the movement of said separation means (2, 7); - means (12, 20, 22) for rotating said shaft around said axis, - means (18, 19) for commanding said rotation means (12, 15, 20, 22); - a shaft rotatable around an axis and connected to said separation means (2, 7), said connection causing the movement of said separation means (2, 7); - means (12, 20, 22) for rotating said shaft around said axis, - means (18, 19) for commanding said rotation means (12, 15, 20, 22); • a rolling-shutter box for containing said shaft; • a lateral profile for containing said rotation (12, 20, 22) and command (18, 19) means, said rolling-shutter box and said lateral profile being mutually connectable, said shaft and said rotation means (12, 20, 22) being mutually connected when said rolling-shutter box and said lateral profile are mutually connected, • at least one first pin (25, 26, 27) that is axially slidable with respect to said shaft but constrained in rotation with said shaft; • a first seat (28, 29, 30) for housing said first pin (25, 26, 27) integrally connected with said rolling-shutter box,