**explain
this app, you can build a simple business communication system in a few minutes with only the surplus smartphones that you no longer use, without the need for physical dedicated buttons and call display devices.
-You can register and call voice with free message.
-The caller reads the URL displayed on the app with a QR code and calls it from another browser such as a smartphone or PC.
-You can replace your intercom system supermarket with this app.

**Notes
- This application is a business communication system used in-house, and it is assumed that it will be used in the in-house local network (IP address starting with http: // 192.168.XX), and the terminal itself on which the application is installed is Become a server. Therefore, network settings are required so that terminals can access each other via L2TP, VPN connection, etc.

- This application needs to keep the top screen running. Please do not turn off the screen because the screen is activated by the application.


**Example of use
It can be used in any industry, such as supermarkets and factories, if it has a purpose to call.
(Example 1) Supermarket: Ask people in the backyard to support the cashier, or instruct them to go to pick up the luggage.