Here are the steps:
- Install Zello from the Play store or from your Zello@Work network.
- Pair the button device with your phone by going to Settings > Wireless & networks > Bluetooth settings.
- Open Zello.
- Go to Menu > Options > Bluetooth PTT control device
- Select the device name in the Bluetooth PTT Control Device selector. A popup should appear indicating the device control has been activated. If you don't see it, you may need to power cycle the headset and repeat.
- Open the Talk screen in Zello (the screen with a big round button).
Now, the PTT button will work with Zello even while running in the background.
Set up Bluetooth for normal audio setup