The AARC-EVAC™ ATC61-R Standalone Wireless Linked Emergency Alert
Repeater Transmitter Unit, incorporates an in-built Battery Backup UPS.
They are fully self-contained making them ideal for use in locations where
there is no existing PA system, or to cover areas not serviced by a PA system
or as a full standalone network of units to provide for redundancy if the PA
system fails for any reason.