When you create a new Local Area Network (LAN) chat, Underpass will automatically listen for a connection. The name of your computer on the network is listed in the settings. Another device can find yours on the network via your computer name. See Basic concepts for more details on network discovery.
If another device on the network is already listening for a connection, you can start a chat immediately if its computer name is selected in your chat settings. This may happen automatically if you haven't already made a selection. Otherwise, you can select the name manually.
Once the device is selected, you can start a chat from the chat window.
You can always stop the chat immediately from the chat window, regardless of which device started the chat.
The computer name selection in the settings will be remembered, so after you stop the chat you'll be able to start again easily without having to select the computer name every time.
If you want either device to be able to start a chat, then each device should select the other device's computer name. For example with two iPhones:
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