The DOM (Digital Output Module) is the central control element of VARIODYN D1. It has interfaces to all input/output assemblies, administers, and monitors the loudspeaker circuits for voice alarm systems and electro-acoustic emergency warning system per EN 60849 and EN 50849. Large or complex system configurations can be implemented through the networking of multiple DOMs via Ethernet. The DOM offers a high level of automatic and constant monitoring as standard. All connected power amplifiers are permanently monitored by the DOM and if a power amplifier becomes faulty, it can be replaced dynamically by a backup amplifier or a backup amplifier channel. The switchover is done automatically by the DOM. The loudspeaker lines are permanently monitored for short circuit, ground fault, and failure as well as impedance deviation. Faulty loudspeaker zones are separated in a non-reacting manner. A DOM contains storage capacity for preset announcements, which can be used for alarm texts and signals (escape alarm, caution signal) and warning signals (gongs). The volume of each source and each amplifier channel can be controlled. Additional filters like parametric equalizer, high-and low pass filter are available.