A transaction control layer for a signaling gateway that encapsulates multiple signaling systems into a single signaling interface for use by an advanced service node deployed in a telecommunications network. The transaction control layer performs call and resource state management functions for the...http://www.google.com.hk/patents/US6418205?utm_source=gb-gplus-share專利 US6418205 - Call and circuit state machine for a transaction control layer of a communications signaling gateway
