The HC-05 bluetooth module is a easy to use transceiver. The modems is design to work as a serial (RX/TX) data pipe, and are a grest replacement for serial cables. Any serial stream from 2400 to 115200bps can be passed seamlessly from your computer to your target. The HC-05 can be programmed as a master or a slave device.
To enter AT mode, press the built-in push button when powering on the module. Once the LED is flashing at 2 second interval, AT command can be passed through the RX pin at 38400bps.
Remember to use 3.3V for serial TTL.