This definition is from CALLERLAB www.callerlab.org.
It is provided here for informational and educational purposes only.
Permission to reprint, republish, and create derivative works without royalty is hereby granted, provided this notice appears. Publication on the Internet of derivative works without royalty is hereby granted provided this notice appears. Permission to quote parts or all of this document without royalty is hereby granted, provided this notice is included. Information contained herein shall not be changed or revised in any derivation or publication.