BtL can provide both progressive diallers and predictive diallers to meet your requirements to work with most phone systems.
Progressive Diallers enable scheduling and management of campaigns of outbound telephone calls, also enabling blending of inbound call levels and comprehensive management reporting.
Predictive Diallers work in a similar manner but are more aggressive as the application predicts when an agent is going to be avaliable so makes a call.
Consequently predictive diallers are generally more suitable for large call centres. Typically Diallers can double the number of calls that each agent can make in an hour, so it is easy to see where the payback is.
If you have a call centre and would like to improve the productivity of the agents then you should at least evaluate the benefits of progressive diallers or predictive Diallers.