Hodgepodge – A bit of everything… 
If you need to install an application that can set all kinds of communications through a corporate LAN, you can use BigAnt Office Messenger, an application that supports up 10 free version users. It is a complete secure instant messaging tool, able to manage chat groups, voice and video calls, File transfers, among other options. The server installation enables centralized management of users, well as a number of technical options, as the configuration of the client application, to be installed in each of the users who connect. The program's interface is very advanced and easy to handle.
The control of the server is given the administrator. You can review all chat logs, search messages and attachments, send notices, gestionar permisos documents shared, and some more. BigAnt Office Messenger also supports Remote Desktop Sharing feature, customization of user profiles, message encryption, creating an original logo, among other possibilities.
BigAnt Office Messenger, as already indicated, offers a free version for a total of 10 users. Works on the latest versions of Windows. There is also a version for Mac and one for BlackBerry smartphones.
Link | BigAnt Office Messenger
