.. _index: Welcome to the |NCS|! ##################### The |NCS| is where you begin building low-power wireless applications with Nordic Semiconductor nRF52, nRF53, and nRF91 Series devices. The SDK contains optimized cellular IoT (LTE-M and NB-IoT), Bluetooth® Low Energy, Thread, Zigbee, and Bluetooth mesh stacks, a range of applications, samples, and reference implementations, as well as a full suite of drivers for Nordic Semiconductor's devices. The |NCS| includes the Zephyr™ real-time operating system (RTOS), which is built for connected low power products. To access different versions of the |NCS| documentation, use the version drop-down in the top right corner. A "99" at the end of the version number of this documentation indicates continuous updates on the main branch since the previous major.minor release. .. toctree:: :maxdepth: 2 :caption: Contents introduction glossary getting_started ug_dev_model ug_app_dev security_chapter ug_nrf91 ug_nrf70 ug_nrf53 ug_nrf52 ug_nrf_cloud protocols applications samples drivers libraries/index scripts release_notes software_maturity documentation .. cheat_sheet