HC-05 is a Bluetooth Transceiver Module and has TTL Output. HC-05 6 Pin Wireless Serial Bluetooth Module is a Bluetooth module for use with any microcontroller.  It uses the UART protocol to make it easy to send and receive data wirelessly. This Bluetooth module is a completely qualified Bluetooth V2+Enhanced Data Rate (EDR). It is 3Mbps Module with 2.4GHz radio transceiver and baseband. It has CSR Bluecore 04, an external single-chip Bluetooth system with CMOS technology and AFH, Adaptive Frequency Hopping, feature.

The HC-06 module is a slave only device.  This means that it can connect to most phones and computers with Bluetooth but it cannot connect to another slave-only device such as keyboards and other HC-06 modules.  To connect with other slave devices a master module would be necessary such as the HC-05 version which can do both master and slave.

Specification and Features:

• Voltage supply: 3.5v to 5v
• Working current: matching for 30 mA, matching the communication for 8 mA.
• Speed: Asynchronous: 2.1Mbps(Max) / 160 kbps, Synchronous: 1Mbps/1Mbps.
• With the integrated antenna and edge connector
• Sensitively: -80dBm
• RF Transmit Power: up to +4dBm
• Supported baud rate: 9600, 19200, 38400, 57600, 115200, 230400 and 460800
• Slave default baud rate: 9600
• Data bits: 8
• Stop bit: 1
• Parity: no parity
• A programmable input-output control
• Supported device: laptop, desktop, mobile, tablet
• Protocol: IEEE802.15.1
• Dormancy current: no dormancy.
• Bluetooth module HC-05 Master and slave Two in one module.
• Use the CSR mainstream Bluetooth chip, Bluetooth V2.0 protocol standards.
• Bluetooth protocol: Bluetooth Specification v2.0+EDR
• Security: Authentication and encryption.