Most of enterprises rely on the outbound call centers which play a very important role in CustomerRelationship Management (CRM) and marketing. Outbound Calls centers that employ predictive dialing system obtain greater productivity and higher service levels by dynamically generating outbound traffic. An algorithm is proposed to provide a trade-off between outbound dialing rate and agent occupation in order to minimize customer's waiting time in the queue. In this paper, we optimize the performance of the presented algorithm. The proposed system uses an analytical method for determining the frequency of calls generation. Evaluations are conducted by means of simulations. We also developed a continuous-time Markov chain (CTMC) to illustrate the system's performances according to some key parameters.