The ratio of the processing time to the waiting time of a call (e-mail, fax, chat, …) is referred to as the occupancy.
Outbound activities are all those activities initiated from the contact center. This can be done in the context of a campaign using a dialer, but it can also be e-mails or social media posts. In this context, it is important that the addressing of consumers has their explicit consent to make contact and that companies have a presumed consent.
Overflow refers to the ability of an ACD in certain situations to forward incoming conversations to other agent groups or even external contact centers.