The HC-05 Bluetooth module is a Bluetooth 2.0 (classic) module that support both MASTER and SLAVE modes. To connect two arduinos then one side be the MASTER. To connect a PC, telephone or tablet to an Arduino via Bluetooth then the HC-06 module is far simpler to operate.

Features:

• Bluetooth v2.0+EDR
• 2.4GHz ISM band frequency
• Supported baud rate: 9600, 19200,38400(default), 57600, 115200, 230400, 460800
• Serial Port Protocol (SPP)
• Speed: Asynchronous: 2.1Mbps(Max) / 160 kbps, Synchronous: 1Mbps/1Mbps
• Power supply: 3.6V to 6V DC
• Default Passkey: 1234

Documents:

• Datasheet
• AT Command
• Tutorial and Connection Guide

Note: Apple IOS does not support Bluetooth Serial Port Protocol (SPP).