If your POS terminals keep disconnecting from each other because one or more of them are automatically connecting to the wrong network, you may need to make the iPads forget that other wireless network so they stay on the same network together.
From the home screen, go to the iPad's Settings.
2. Go to Wi-Fi. The network with a tick next to it is the one that you are connected to.
3. Press the information (i) button next to the network you wish to forget.
3. Press Forget This Network. The iPad will disconnect from the network and it will not attempt to connect to this network in the future.