["4duino HC-05 Wireless Bluetooth module 6pin B-60 (B39) The module with the HC-05 can also be configured as a master. This means that an HC-05 module can automatically connect to a specific other Bluetooth module (e.g. an HC-06 module). For example, two Arduinos can contact and communicate with each other. Both modules HC-05 and HC-06 can be connected directly to 5 V because they have a voltage regulator that reduces the connection voltage for the Bluetooth chip to 3.3 V. The TXD / RXD connections also work smoothly with the Arduino's 5V TTL voltage level. The hardware supports the AT command set for setting the baud rate from 2400 to 1382400. The standard settings for the serial port is [9600, N, 8,1], password: 1234. The AT command set can be used to change the baud rate, device name, passkey, master or slave mode. Details: \" Bluetooth protocol: Bluetooth Specification v2.0+EDR \" USB protocol: USB v1.1/2.0 \" Frequency: 2.4GHz ISM band \" Modulation: GFSK(Gaussian Frequency Shift Keying) \" Transmit power: =4dBm, Class 2 \" Sensitivity: =-84dBm at 0.1% BER \" Rate: Asynchronous: 2.1Mbps(Max) / 160 kbps \" Synchronous: 1Mbps/1Mbps \" Security features: Authentication and encryption \" Support profiles: Bluetooth serial port (master & slave) \" Power Supply: +3.3VDC 50mA \" Working temperature:", "5 ~ +45 centigrades"]