BlackBerry mobile phones operate on wireless networks to receive calls and data services; their connection to the network is provided by what BlackBerry calls the "radio." Sometimes, you may need to use your device without a cellular network connection or wireless transmission; BlackBerry devices can also operate without the radio turned on. The radio on your BlackBerry will also automatically turn off when the battery is too low for the device to operate the cellular network connection. You will have to manually turn the radio back on after the battery is again fully charged.
Navigate to the "Home" screen on the BlackBerry handheld. Locate and select the "Manage Connections" icon. A menu will open up.
Find the "Mobile Network" selection. If the radio is turned off, there will be no check mark in the box next to "Mobile Network."
Select the box next to "Wireless Network." Once selected, all radio frequency will turn back on; this means that wireless communication will occur between the handheld and your wireless service carrier.