Minecraft – Simple Voice Chat
As the name suggests, Simple Voice Chat adds a simple voice chat to your Minecraft server. This can then be used via voice activation or push to talk.
You can download the mod directly on Curseforge.
Important The default key for Push to Talk is Caps Lock. However, you can change it. To enter the settings for the mod, press V on the keyboard.
In order for the mod to work correctly on your Minecraft server, it is necessary that you make a few special settings. The lines for this are:
In the bindip line you enter your server IP. After that you have to enable a port for the voice chat. You can find more information about this HERE.