What are the commonly used enterprise address book software?

Recommend the first enterprise letter, with a clear organizational structure and enterprise address book, so that managers can quickly find relevant personnel through various communication methods, such as instant messaging, ip phone calls, network meetings, etc., according to their work needs. They can know the progress of work, the difficulties they encounter and what help they need in real time ... Real-time communication and real-time management, information and work are highly matched, and promote the rapid development of work!