By default the bluetooth module HC-05 sets baud rate at 38400, data bits 8, Stop bits 1

All schematics of this bluetooth module can be found at : http://pan.baidu.com/s/1o6BiNDS

I used a USB-> TTL usb module connecting to the bluetooth module.

Rx -> Tx on bluetooth module

Tx -> Rx on bluetooth module

Vcc -> 5v

GND -> GND

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getting into AT command line

Hold the key on the bluetooth module when powering it on,

then connect to serial ports on Linux using CuteCom

IMPORTANT:

TRY : CR,LF line end 

OR there will be Error (0)

Set serial port baud rate

     AT+UART=57600,1,0

                        baud rate, Stop bits, Even check,             ( The AT commands doc provided above in Chinese is wrong. This command is the correct. I verified ! )

     Why 57600? Because the tele transport module of drone flight controller board APM 2.6 is going to need this baud rate.: http://ardupilot.org/copter/docs/common-3dr-radio-advanced-configuration-and-technical-information.html

     This works with 3DR radio firmware version  1.7 - 1.9 by default.

Set the bluetooth module broadcasting name

      AT+NAME=‘tele‘

Check version

     AT+VERSION?

Try the module: Phone <-> Bluetooth <-> PC

Use an app called "Bluetooth Terminal HC-05" to connect to the working bluetooth module.

Find the bluetooth module named tele and input password 1234

(By default password is 0000 or 1234)

Open app  "Bluetooth Terminal HC-05" select CR(Carriage Return), LF (Line Feed).

Connect the bluetooth module with the USB->TTL dongle to PC and power it on normally.

Use CuteCom connect to /dev/ttyUSB0 , Baud rate: 57600, Data bits 8, Stop bits 1. 

Send something from phone to PC, then from PC to Phone. It works like a charm!

Will show how to set bluetooth module with 3DR radio 433Hz transmitter in next blog.

HC - 05 bluetooth module settings in Linux using CuteCom