DTMF Telephone interface for AXD series amplifiers. It allows to access the Public Address system from the telephone system, with priority over the rest of the amplifier inputs, except the Emergency one. As it is a priority input, it is not affected by the amplifier general volume and it includes its own volume adjustment which has to be preset in the moment of the installation. The telephone connection is made to an analogical telephone central or to an analogical telephone extension, with DTMF tone dialling type.