Definitionen
1.Nouna message sent in the forward direction that contains (a) address information, (b) the signaling information required to route and connect a call to the called line, (c) service-class information, (d) information relating to user and network facilities, and (e) call-originator identity or call-receiver identity.
2.Noun↑ Telecom Glossary 2000 (Accredited Standards Committee on Telecommunications, T1)