PA 100 is an installed sound amplifier that can operate with low impedance or 70/100 V line loudspeakers. The operating mode is selected mode is selected through a switch in the rear side and a dispswitches block which has some terminals reserved for future improvements. It incorporates a unbalanced LINE input with its own volume control and LEDs which mark the signal presence anda clip mode. In the rear side is allocated a RJ45 connector which admit RS485 command from an external device in order to control some features.