VA2000MS is an amplifier auto changeover which is used to automatically switch into standby amplifier when the main amplifier has fault. The backup modes are flexible and configurable by customer, as there are options one standby for eight, two standby for eight, three standby for eight and four standby for eight even more, in one word, it is builtin a four by eight matrix changeover, which helps to developed an changeover meets both most economy solution of one standby for eight and most reliable solution for four standby for eight. The amplifier auto changeover could be used stand alone or integrated into the VA-2000 voice evacuation system. The standby mode will be set up in the system software configuration.