ACD offers extensive overﬂow options for each ACD Group. For example, a caller ringing in when all agents are unavailable can hear an initial announcement (called the 1st Announcement). This announcement can be a general greeting like, "Thank you for calling. All of our agents are currently busy helping other cus- tomers. Please stay on the line and we will help you shortly." If the caller continues to wait, you can have them hear another announcement (called the 2nd Announcement) like, "Your business is important to us. Your call will be automatically answered by the ﬁrst available agent. Please stay on the line." If all the ACD Group's agents still are unavailable, the call can automatically overﬂow to another ACD Group or the Voice Mail Automated Attendant. If all agents in the overﬂow ACD Group are busy, Lookback Routing automati- cally ensures that the waiting call will ring into the ﬁrst agent in either group that becomes free.