I have a Nexus 4 with a limited calls & data plan. I will be leaving the country and it will cost big bucks if I receive any calls. So I will use WiFi. I would like to disable the cell phone without removing the SIM and still use WiFi. So "airplane mode" is not suitable. I know I can go into Settings > Wireless & Networks > Mobile Networks and uncheck "Enable data access over Mobile network." But is there a way to turn off the cell phone completely?