This small size Bluetooth 4.0 TTL transceiver module allows your target device communicate with your iPhone/iPAD, Android 4.3 above devices. It's easy to use and completely encapsulated. You can set it as slave or master. You can use AT command set the baud rate. PIN definition: STATE -You can connect a external LED to indicate the Bluetooth state. It is same as the state LED on the module. RXD -Receive data TXD -Send data GND -Power ground VCC -DC power in (3.3V-6VDC) NC Specifications: TTL data transparent transfer between a host Bluetooth device(IOS or Android 4.3). Ultra-low standby power consumption 400uA ~ 800uA Default Baud Rate: 9600,8,1,n. Coverage up to 60 meters Built in antenna Power input: 3.6V-6VDC(Can not higher than 6V) Document: User manual Bluetooth BLE/EDR setting tool iPhone test APP Android test APP 4.0 BLE Android Source code 4.0 BLE IOS7 Source code