These are two popular modules available in market- HC05 and HC06

I bought two HC-06 modules and trying to establish communication between them.

But I failed and a friend of mine said it can be only be used as slave. I verified this by establishing a successful communication between a laptop with Bluetooth, and this module with a Controller board.

But I am not able to understand why this module is made in such a way. Is it not possible to change the mode to master using some software upgrade ? If yes how ?


2 Answers 2


The HC-05 and HC-06 are identical, except the firmware they get shipped with. For whatever reason, the HC-06 has a simpler, slave only firmware. The HC-05 has a much more completed command set. There was some attempts to reflash or change the firmwares on these but the projects were a bit obscure. It's just cheaper and faster to get the HC-05 or a newer master capable bluetooth module.


I do have those too but you need to send AT-commands to the module to switch it to master mode and establish connection. You need to refer to the manufacturer's manual for this.

  • \$\begingroup\$ You mean using AT commands one of it can be switched to master mode? can you send the link that describes this procedure? \$\endgroup\$
    – user25108
    Mar 20, 2015 at 11:22
  • \$\begingroup\$ @user25108 This may help. \$\endgroup\$ Mar 20, 2015 at 11:25
  • \$\begingroup\$ According to that link "HC05 can act as both master and slave whereas HC06 functions only as slave". \$\endgroup\$
    – user17592
    Mar 20, 2015 at 11:34

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