CCM8 changeover is an integrated controller supporting main and backup amplifier switching, speaker circuit grounding, detection, open circuit and short circuit detection, compatible with three or four wire volume controller wiring, without extra wiring or power supply, combining 8 programmable stem mode or wet mode trigger input and 8 programmable on-line output signal. It works with class-D digital amplifiers or power amplifier to provide a safe affordable solution to the PA & Voice Alarm System.