The ISUP service provides the following asynchronous functions:
Function |
Description |
Requests the establishment of a circuit switched connection. | |
Signals the far exchange that an incoming call was answered. | |
Sends connection status information to the far exchange during the connection establishment phase. | |
Sends a global or circuit-specific message to the far exchange. |
Function |
Description |
Sends user-to-user information associated with an established connection to the far exchange. | |
Resumes a suspended connection (cancels timer T2) and sends a resume message to the far exchange. | |
Sends a suspend message to the far exchange and starts the suspend timer T2. |
Function |
Description |
Clears or denies the establishment of a circuit switched connection. | |
Responds to a release indication from a far exchange. |
Function |
Description |
Sends a facility request message to the far exchange. | |
Retrieves congestion level activity statistics from the ISUP service. | |
Sends an application-encoded ISUP packet. | |
Retrieves the next message from the ISUP layer. |