BC04-BK Bluetooth Serial Module Master&Slave

(8 customer reviews)


SKU: NBL1022 Category: Tags: , ,


This is a master and slave in one module, switch by using AT commands.

This module also includes the base board, not only the core board, most functions are pre-set, so only the serial port communication is available but it’s more easy to use.

Communication compatible with other similar Bluetooth serial module: LC-05, HC-05


  • Based on bluetooth module BC04-B.
  • Use CSR popular buletooth chip, bluetooth V2.0 Protocol standard.
  • Serial port operation voltage 3.3V
  • Customize by AT commands for: baudrate, memory mode, module name, master/slave
  • Baud rate set at 9600, customization is possible.
  • Operation current, pairing at 30MA, after pairing is 8 MA during communication
  • sleep mode current: no sleep mode
  • Widely use for wireless data communication such as GPS navigation device, remote data collection, PDA devices
  • Also can pair and communicate with laptop, laptop bluetooth adapter, PDA devices
  • Be aware default setting of the product is slave mode, communication only available between master and slave mode, but not master and master, or slave and slave mode.
  • Board silk pring RXD means you need to the connect the RXD port of another device, and same for TXD port.
  • R2 version add software and hardware master/slave mode select, default is software on. To use hardware select, need cut off connection on software ON with middle pin first.
  • Each purchase if for one piece only.

Setup Mode:

  • Bottom jumper set hardware / software method for slave / master mode, Default setup for hardware method.
  • Top jumper set for slave / master mode.
  • If you prefer to use software method by AT commands to change slave / mater mode, cut the bottom jumper connection (GND – middle pin), then re-connect to top by solder (VCC-middle pin).


Additional information

Weight 0.01 kg

8 reviews for BC04-BK Bluetooth Serial Module Master&Slave

  1. Duncan

    The description says it can go into master, however whenever i set role to 1 (master) and try run the master commands it gives error 303, which according to the documentation means “it needs to be in lord mode” which I am assuming is master mode. it always resets to slave mode after reset. Slave mode works fine though I bought these specifically for master mode.

  2. Duncan

    I think i found the problem. Pin 4 is supposed to be set to HIGH for software master/slave to work, instead it is wired to low.
    So by default this module will not work.

  3. Duncan

    Ps, error code is 302, not 303

  4. Duncan

    Raising pin 28 on startup puts it in master mode, had to solder a connector to the board it self to do this, not ideal

  5. Chao (store manager)

    Hi, yes indeed, this is a problem, will fix this and contact you for details. Thanks for point this out.

  6. Duncan

    Soldering pin 12 (the 3.3v) to pin 27 (the HW/SW role select switch) fixed it. It now works with software role select.

  7. whYNKay

    “Key” button is not working. I can’t go into AT command mode. I checked the connectivity of the button labelled as “Key”, one pin of that button is connected to 3.3v but I can’t find any connection to the other pin with the pins of the main board.

  8. Chao (store manager)

    Key button is for clean pairing configuration. Connected to pin 5 on right, from bottom to top. Please double check.

    When not pairing, you can use AT commands, when paired you can not use anymore.

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