I'm looking for software that can be used for voice chatting through LAN. The software will be mainly for home use and while playing LAN games. Due to our spotty Internet connection, and to avoid quickly reaching the bandwidth cap imposed by our ISP, we'd rather play through and talk through LAN.

Requirements: 

* Does not require an Internet connection to use, only a LAN connection
* Works on Windows 7

Preferably:

* Can detect when a computer in the LAN has the software running and can be called
* Easy to setup and use
* Can call a computer by its IP address
* Has good audio quality
* Freeware

We've already tried the [SSuite Voip PC Phone Extreme](http://www.ssuitesoft.com/voippcphonelanchat.htm) software, and it does fit my requirements and most of my preferences, but its audio quality is unacceptably low as per our tests.