The path of an incoming call is as follows. A caller telephones your contact center via the Public Switched Telephone Network (PSTN). (The PSTN is a global collection of Central Offices (COs) interconnected by long-distance telephone switching systems.) The local CO directs the call to one of your trunk groups. An available trunk picks up the call. Typically, calls from the PSTN arrive to the contact center over incoming trunks and calls from the contact center to the PSTN travel over outgoing trunks. If no trunks are available the call does not get through to the system (it is blocked) and the caller receives a busy signal.
When a trunk picks up a call, it forwards it through to a group of agents handling calls, or to some other answering point. The call arrives at the ACD queue of an agent group. The queue delays the call rather than blocking the call from entering the system. The length of time the caller waits in queue is the queue time. While waiting in queue, the caller listens to product features, announcements, or other messages provided by a Recorded Announcement Device (RAD). The caller can wait patiently in queue for an available agent, leave a voice mail message, or hang up (abandon) the call. (See the following figure.)
An agent handles the call. The time the caller spends talking to the agent is the ACD Handling Time (including the hold time). If the agent calls the supervisor in search of more information (while the caller is on hold) and/or transfers or conferences the call, these times are added to the ACD Handling Time value.
For example, an agent speaks to a caller for two minutes and then puts the caller on hold for three minutes and tries to solve the problem. This may include a call to the supervisor. The agent then initiates a conference call with the caller and a third party and they speak for three minutes and resolve the issue. Therefore, the ACD Handling Time for the agent is 2 + 3 + 3 = 8 minutes.
When the call is completed, the agent might need to perform additional work associated with the call. The time taken to perform this work is the Wrap Up Time.
