The commissioning phase of the first Large-Sized Telescope (LST-1), the first out of four in construction for the northern site of the Cherenkov Telescope Array Observatory (CTAO), is almost completed. The LST-1 is a prime focus ground-based gamma-ray telescope with a 24 m diameter and 28 m focal length parabolic dish, inaugurated in October 2018 at Observatorio del Roque de los Muchachos (ORM), La Palma (Spain). The LST-1 is equipped with a camera Calibration System (CaliBox), placed at the center of the mirror dish, that uniformly illuminates the Camera at the telescope focal plane 28 m away. The intensity of the light beam and its time characteristics permits to calibrate the Camera response to shower events. Here we describe the CaliBox mechanical structure, the optical performance, the new internal-calibration hardware and software system including the definitive OPC-UA Server protocol logic used to manage the CaliBox and the internal sub-systems.
