A method for providing a navigation tool of a user interface for an industrial control system. The camera emulation server produces a logical digital video stream emulating a real video surveillance camera, in which the logical digital video stream includes data other than original video surveillance data. The active region may be formed in a first zigzag pattern andor the gate may be formed in a second zigzag pattern in symmetry with the first zigzag pattern. The retaining elements are flexible, and may be O-rings. The movable contact always slidably contacts the fixed contact.