# Principles of operation Hideez Key interacts with workstations via radio frequency signals specified by Bluetooth 4.0 Low Energy standard on the 2.4 GHz frequency bandwidth. This standard requires minimum power consumption and uses data encryption during transmission. The stable connection distance can reach up to 100 meters outdoors without obstacles, or up to 25 meters indoors. The actual signal strength and range of the connection depends on the surrounding obstacles, including human bodies, that can influence the operating range and performance of certain functions. Hideez Key can approximately measure the distance to its paired devices using the received signal strength indication (RSSI). This feature is the basis of most security and signaling functions. Hideez Key 4 is equipped with an NFC module, which allows it to be used for FIDO2. Hideez Key is also equipped with an RFID module that works on the 125 kHz frequency bandwidth. You can learn more about RFID [here](/hideez-key-enterprise-edition/key-for-physical-doors.md). Operating Hideez Key with Bluetooth requires the Hideez Client installation on a paired workstation. A detailed manual of the installation process can be found [here](/hideez-client-app/windows-deployment.md). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://enterprise.hideez.com/hideez-key-enterprise-edition/principles-of-operation.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.