It is a power amplifier with a receiver board built in. When a signal from the telephone line arrive, the amplifier is turned on and the audio signal is connected to its input. At the end of the message the amplifier is turned off automatically and the system returns in stand-by status waiting for a new message.

• The device provides the following features:
• An input translator to connect the apparatus to the telephone line.
• A receiver for the signal that controls the ON-OFF status of the power unit P.U.
• An amplifier to increase the received audio signal to the level for driving the P.U.
• A -TEST- push button on the front panel for control the efficiency of the power unit during the installation and maintenance operations.
• Output power 75W or 120W.
• Outputs 4-8-16W and 70/100V with output transformer.