This counter tracks the number of CONNECT messages, sent when the called party accepts an SVC and the call is ready to become active that this port has received, per the description. This is the PDU that actually indicates a successful call, so it's the number an admin compares against NumSetupPdu to compute a real connect-success ratio for the port rather than relying on the failed-call table alone. For example, a port doing 5,000 SETUPs but only 3,000 CONNECTs per hour is running at a 60% completion rate, which would warrant investigating the cause codes in svcAtmConfigQ93bLastCauseRx.