1# Cellular Data 2 3### Introduction 4 5This sample shows how to use cellular data APIs to obtain SIM card information. 6 7### Usage Instruction 8 91. Set the default SIM card. The default SIM card is rendered with a blue background. 10 112. Enable or disable the mobile data service. **Turn On** is displayed if the mobile data service is enabled, and **Turn Off** is displayed otherwise. 12 133. Enable or disable the roaming service. **Turn On** is displayed if the roaming service is enabled, and **Turn Off** is displayed otherwise. 14 154. Check **Data Flow Type** for the data flow status of the default SIM card. 16 175. Check **Connect Data** for the data connection status of the default SIM card. 18 19### Constraints 20 211. This sample can only be run on standard-system devices. 22 232. The device must support the SIM card function and have a SIM card installed. 24 253. This sample demonstrates the stage model, which supports only API version 9. 26 274. This sample requires DevEco Studio 3.1 Canary1 (Build Version: 3.1.0.100) to compile and run. 28