Windstream's DTO (Direct Trunk Overflow) enables business continuity on a local T-1 or higher voice line for inbound calls in the event of a service impairment or should all available circuits be in use.
Direct Trunk Overflow Application Brief - "Provides customers with redundancy and the ability to transfer inbound terminating calls to an alternate path, in the event of maximum trunk capacity or a trunk service outage"
Business Continuity Brochure - "Provides a comprehensive blend of services and solutions that can be tailored to create a personalized business continuity plan that fits the specific needs of your business"