A free program for Android, by NAVA Apps.
BSim Wifi Walkie Talkie Pro is a free, simple and easy to use app that allows you to talk to other devices on the same WiFi network without the need for an internet connection. The app is a combination of a walkie-talkie and a chatbox, so you can communicate with other users on the same WiFi network. The app does not need any additional hardware or plugins, it is completely free, simple and easy to use.
How to Use:
First, you need to download BSim Wifi Walkie Talkie Pro on your device and install it. After installation, you need to open the app and start the connection. You will be able to see all the available devices on your screen. To talk, you need to hold the PTT key and start talking. The app will automatically detect the available devices and will show you the list of them. You can see the name of the device, the IP address, the MAC address, and the device’s status.