VICIdial is an enterprise class, open source, call center suite in use by many large call centers around the world.
VICIdial has a full featured predictive dialer. It can also function as an ACD for inbound calls, or closer calls coming from VICIdial outbound fronters. It is capable of inbound, outbound, and blended call handling. VICIdial even allows you to have agents logged in from remote locations.
The VICIdial agent interface has been translated into Spanish, Greek, German, French, Italian, Polish, Portuguese, Slovak, Russian, Dutch, Traditional Chinese, and Brazillian Portuguese. The VICIdial admin interface has been translated into Spanish, French, Greek, German, and Italian.