A payphone/operator services term. This software feature lets callers place collect and third-number billed calls without speaking to a live operator. Call acceptance is validated using a synthesized operator's voice ("Will you accept a collect call from...") and a digital recording of the caller's voice ("Mary"). Calling card services are automated in a similar way. One publication ("The Operator, Volume III, Number 7, April, 1996) put it this way: "Automated Alternate Billing Systems (AABS) have driven substantial costs out of the network with little or no adverse impact on the service that is delivered."

An incoming call answered by your ACD, which is terminated by the person originating the call before it is answered by an agent. Usually the caller hangs up because she feels she has waited long enough. (But there are other reasons.) ACDs generally keep statistics on how long your callers wait before disconnecting and what percentage of your calls end this way. This is valuable information to have when planning service levels or creating message-on-hold announcements. Your service level should aim to have most calls answered within the length of time your average caller hangs up. Your message on hold should take into account the amount of time your callers spend waiting for you. Your message should be longer than the average person waits. Using a message on hold can reduce the amount of abandoned calls you have.

There is another, less common use of the term abandoned call...