You may want to host local calls between persons on your community network. Due to the small size of a low power network this may have limited utility. However in certain situations, such as a office building, school or apartment complex this might provide a quick way for users to communicate. This is also one of the most resource intensive uses of your network. At most 10-20 users could be connected at any one time. This would divert resources away from other uses of the server.
Mumble/Murmer – Mumble is the client and Murmer is the server software for this voice chat application. The Mumble client is available for Linux, Mac OS and Windows. A wide varaity of users can easily connect to and use the Murmer server software. In addition there are instructions for installation on a Raspberry Pi.
Text chat is useful on a community intranet than a voice chat application. It is lighter on system resources and more amenable to a quiet environment such as a library or school. It can allow quick communication between scores of users throughout a local community.
ejabberd – This is a XMPP or Jabber server. XMPP is the protocol used by Google talk chat services. This is a lightweight chat server and there are a multitude of XMPP clients available for every type of operating system.
VOIP stands for ‘voice over IP’. The above voice chat is one method of VOIP communications. However the advanced user might want to connect his voice communication to the wider telephone network. It is possible to enable users to connect their voice communication on the local network to the international telephone network. This use of your server is very processor intensive but may have some applications. It can be a cheap way to share a phone line among several local users. I places with limited cell reception the server might be placed in a location with cell reception to share the voice connection with local users.
Asterix for Raspberry Pi – This is a project to run a VOIP gateway on a Raspberry Pi. With the addition of a cell modem or other telephone connection your Raspberry Pi can share the voice connection with several users.