Patent attributes
The usage of communication systems is improved. An IM server 4 manages presence information regarding each of IM clients and usable media and user information such that each of the IM clients can obtain these kinds of information. In order to perform text chatting, the IM server 4 manages a connection between each of the IM clients participating the chat and the IM server 4, merges text from each of the participating IM clients and distributes the result to each of the participating IM clients. In order to perform voice chatting, an AP server 5 manages a connection between each of the IM clients participating the chat and an MD server 6, mixes voice from each of the participating IM clients except for a focused IM client and distributes the result to the focused participating IM clients. This processing is performed for each of the participating IM clients.