By muting all channels, you will prevent PTT audio messages from playing automatically for all channels you have in your channel list. Messages you receive will still display in the chat history and notifications will still come through if enabled.
To mute all channels:
- Tap the speaker icon near the top right on the channel list
- Tap "Sure" when prompted for confirmation to mute all channels
- Note the speaker icon in the top right has changed to indicate all channels are muted
- Tap the icon again to un-mute all channels