You are here: CSP Developer’s Guide: Common Channel Signaling > 4 SS7 Call Control for ISUP > MPM/CCL/OPR
Overview
This section includes information and call flows related to MPM/CCL/OPR. MPM, CCL and OPR messages are implemented as defined by CHINA ISUP specifications.
Meter Pulse Message: A message is sent in the backward direction after Answer at equal intervals (usually every one minute).
Calling Party Clear Message: This message is sent in the forward direction when the calling party, which has called the special service node, wants to release the call.
Operator Message: This message is sent in the backward direction from the special service node if the calling party needs to be provided with a ring after hanging up.
Calling Party Clear—Normal Release Sequence
The normal release sequence for Calling Party Clear (ITU). The call flow starts with the call in the answered state:
Host 1 = Calling Party
Host 2 = Called Party
Calling Party Clear—Operator Callback—Subscriber Re-answers
Shows the normal release sequence for Calling Party Clear (ITU) with an operator callback. The call flow starts with the call in the answered state:
Host 1 = Calling Party
Host 2 = Called Party
Calling Party Clear—Operator Callback—Re-Answer Timeout
This call flow shows the normal release sequence for Calling Party Clear (ITU) with an operator callback and a re-answer timeout. The call flow starts with the call in the answered state:
Host 1 = Calling Party
Host 2 = Called Party