Feature is useful for managers or senior agents of call centers. It allows monitoring phone calls between agents and clients. Silent monitoring is usually used for educating purposes, but on continuous basis in order to ensure the quality of service provided to clients and to improve productivity. At the same time, before the connection with the agent, the caller has to be informed that the conversation will be monitored with the purpose of improving service. The agents however are not aware of the fact that they are being monitored.