# 25 Years of Bluetooth Technology
## 4 Communication between Bluetooth and Zigbee
### Bluetooth-Zigbee Interoperability  
Interoperability is important for the large-scale adoption of the IoT [18]. To enable interoperability between Bluetooth and Zigbee, a gateway device should be implemented that converts between Bluetooth and Zigbee data formats. An example of such a gateway is the BlueBee system [19]. Bluebee is a gateway that translates data from Zigbee devices to Bluetooth data. The BlueBee node contains two main modules to manage the system activities: Data Communications Equipment (DCE) Module and Digital Terminal Equipment (DTE) Module (as shown in Figure 10).  
THE DTE module is used to configure the node and show data transmitted between nodes. The DTE module includes specific modules as follows:  
* _dsPIC Microcontroller_: Node settings are implemented via ATtention (AT) commands transmitted to the DCE module.
* _Graphic Liquid Crystal Display (GLCD)_: GCLD allows the user to see various system settings and messages.
* _Keyboard_: Allows the user to type in text values.
* _RS232 transceiver_: Changes the RS232 voltage levels to UART voltages.
* _Reset button_: Helps restart the DTE module.  
The DCE module includes the following components:  
* _Zigbee module_: It is an Original Equipment Manufacturer (OEM) serial port adapter OZS311i Zigbee/IEEE 802.15.4 module launched by ConnectBlue [20], a manufacturer for data products and solutions. The OZS311i is an IEEE 802.15.4 implementation, with an internal antenna of approximately three-hundred-meter range.
* _Bluetooth module_: This is the OEM serial port adapter OBS433i that is a long range Bluetooth 2.1+EDR module (class 1), with support for the Serial Port Profile (SPP) for fast and secure transparent serial data transmissions, and the Personal Area Networking Profile (PAN). It is worth  
Figure 10: BlueBee: Bluetooth-Zigbee gateway [19]. Reproduced with permission from [PERSON] et al., IEEE 2011.  
noting that the Serial Port Profile specifies the utilization of the Radio Frequency COMMunication (RFCOMM) protocol to emulate RS232 cable communications [21].  
A Bluetooth module has different operating modes (as discussed below), which determines BlueBee's connectivity as well as discovery of other BlueBee nodes. SPP defines serial connections. The BlueBee node can work in discoverable or non-discoverable modes. The Zigbee mode can allow or disallow Zigbee in the BlueBee node. The Zigbee Mode allows works in both discoverable and non-discoverable modes.  
The Zigbee Channel Mode connects with other Zigbee devices utilizing the radio channel and implements authentication using Zigbee security mode. The BlueBee node can manage both Bluetooth and Zigbee, and convert Zigbee data into Bluetooth data (in the BlueBee Data Mode), but not vice versa. The BlueBee node transmits data using Bluetooth and Zigbee. For a successful transmission, a user must be active and have Bluetooth and Zigbee modules configured. This resets the operation mode of the BlueBee node to data mode for a successful connection with the respective devices [19]. The combination of Bluetooth and Zigbee WPAN technologies can be used to deploy sensor networks that can be utilized in Industrial IoT (IIoT) [22; 23] for location services [24; 25], as well as for capturing various types of environmental data [24; 26]. Both solutions provide low-cost and low energy consumption solutions for designing embedded systems.