The ANSBKUP switching card continually monitors primary amplifier for signs of failure. Should the amplifier fail, the ANSBKUP automatically activated a backup amplifier. A single amplifier can be used to back up one or more amplifiers of equal or lesser wattage. One ANSBKUP is required for each amplifier being backed up. The backup amplifier does not require its own microphone and digital message repeater unless a fully redundant voice evacuation system is required.