ASAI and Call Control
■Attempting to use a Trunk Access Code (TAC) to access a PRI trunk (only Automatic Alternate Routing/Automatic Route Selection [AAR/ARS] feature access codes may be used to place a
■No classifiers available
(cause CS3/21 — Classifiers not available)
■Resources not available (for example, time slots or association records) — NAK/Return Error component (cause CS3/40 — Resources not available)
■Receipt of a RELease COMplete message from the adjunct.
These conditions result in a Third Party Call Ended message.
ECS Operation for Switch-Classified Call Setup
This section details the ECS actions for each stage of call setup.
After the initial alert event is reported, the ECS waits for the call to be classified as answered or dropped. The Alerting Event Report is sent to the adjunct only for the first ringing occurrence.
If Call Classification after Answer Supervision is enabled, the ECS will rely on network answer supervision to classify the call. A call classifier will only be attached after the call is answered and only if answer machine detection is requested.
If network answer supervision is received before the classifier detects answer, the classifier is disconnected. If the classifier detects the answer, any subsequent network answer supervision indications are ignored. 2
After the answered event is reported (call answered at the called party), the ECS terminates the call at the originator specified in the Third Party Make Call request. Valid originators are ACD split extensions, hunt group extensions, announcement extensions, or VDNs.
When the ECS determines that the originator (ACD split) can accept the call, the call is transferred to the ACD split (the sequencing is done internal to the ECS). The event report sent to the adjunct depends on whether the call has been delivered to an available agent/extension or has been queued. If the call drops prior to getting to the originator, the Third Party Call Ended Report is sent to the adjunct.
If the call has been queued, the Queued Event Report is sent to the adjunct. When the agent becomes available, the call is
2.See Answering Machine Detection operation for G3V3 and later ECS releases in this section.
