JBoss.orgCommunity Documentation
The ISDN User Part ( ISUP ) is a protocol used to set-up, manage, and release trunk circuits voice carry voice and data between terminating line exchanges (e.g., between a calling party and a called party). ISUP is used for both ISDN and non- ISDN calls. However, calls which originate and terminate at the same switch do not use ISUP signaling.
ISUP
is defined in
ITU-T
Q.763
specification.
ISUP supercedes TUP (Telephony User Part) as the standard for call control between telephone exchanges.