We study a problem where manager of a call center should optimally allocate available resources (man-hours) to call handling and document creation (for knowledge management) tasks. The call center helps service engineers (performing equipment maintenance at client sites) in resolving problems that engineers face during the maintenance activities. Often when an engineer calls, he/she has to wait in a queue when all the call center professionals are busy, leading to wastage of production hours of the engineer. To avoid this situation, call center professionals also create documents addressing problems commonly faced by the engineers and make them available to the engineers through a knowledge management repository. Thus, the problem is to find an optimal allocation of call center resources so that the average waiting time in the queue is minimized. We analyze the model that reveals several important and counterintuitive insights and provide guidelines for managers of the call center.