a signal message sent as the first message in a call set-up process which contains sufficient address information to enable the routing of the call to start: it may possibly contain all the address information Found on http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=714-11-10
a signal message sent as the first message in a call set-up process which contains sufficient address information to enable the routing of the call to start: it may possibly contain all the address information