GLOSSARY: All Trunks Busy

All Trunks Busy (ATB) also called as All Trunks Occupied (ATO) is the term that is used in the back office for when all trunks or circuits leading into the call center are being used or busy. ATO May occur when all trunks are occupied with calls, or when some portion of trunks are blocked by system user in periods of understaffing to minimize number of calls in queue.