Find a LAN voice chat software

Find a local area network voice chat software-general Linux technology-Linux technology and application information, the following is to read details. In the past two days, my boss has arranged a job for me to build a LAN voice chat platform for linux. My younger brother has never been in touch with linux and installed a linux virtual machine with the help of others, however, I cannot find the software. The company requires open-source software to enable voice communication in a LAN consisting of several computer linux systems. Text Chat is not required, however, most of the open-source software is on an English website, and I don't know how to find it. Which Big Brother can help me find one? I really don't know about linux, here thank you first, younger brother QQ is 393925750, mailbox is bloodyblackcell@163.com
The system I installed is the debian, 2.6 kernel. If there is a speech software that does not support this system, I can change the system. I am afraid that I will not be able to find the software, thank you !!!