Call screening is the process of evaluating the characteristics of a telephone call before deciding how or whether to answer it.
Some methods may include:
listening to the message being recorded on an answering machine or voice mail.
checking a caller ID display to see who or where the call is from.
checking the time or date which a call or message was received.
prescreening callers to a request line at a radio station or call-in talk show before they are allowed on the air From Wikipedia
