HCI empowers a host controller for IEEE 1394 equipment to communicate with a host controller driver in software. Host Controller is an interface that empowers a FireWire host controller to communicate with a driver. Host Controller Interface (Bluetooth) in Bluetooth protocols. HCI doesn’t get the register and the memory areas of a Bluetooth device straightforwardly. All things considered, it transmits command and information packets to the device and receives information packets and event-message packets from this device.