I have followed the directions from the site below for bluetooth comm between an Arduino board using the HC-05 and an smartphone. It works fine.

The problem is that I need to measure the RSSI from my phone and using the command AT+INQ the response from the HC-05 is "OK" and nothing else.

I paired both devices using my phone as master and the HC-05 as slave, and when I am sending commands to the HC-05 through the Arduino, the pin KEY from the HC-05 is set to high (3.3V).

Do you have any suggestion to solve the problem I am facing?

  • \$\begingroup\$ You should perhaps set inquire mode first? Using AT+INQM command. \$\endgroup\$
    – zgrkpnr89
    Commented Jul 20, 2015 at 23:53
  • \$\begingroup\$ I have not set/changed any parameter, and the default configuration is: ROLE=0, IAC=9e8b33, CLASS=0, INQM=1,9,48, IPSCAN=1024,512,1024,512. Also I have initialized SPP using AT+INIT before using the command AT+INQ \$\endgroup\$
    – gus
    Commented Jul 21, 2015 at 16:13

2 Answers 2


You have to set the module in MASTER mode to determine RSSI values. So the ideal method would be as follows:


AT+INIT will initialize SPP,after which making CMODE=1 enables all devices to connect and then you set the module in MASTER mode(by default it is in SLAVE mode, and hence you will not be able to determine RSSI). After this the procedure is almost same as you have mentioned.



AT+CLASS=0 solved my issue. It was only looking for a specific class devices.

  • 1
    \$\begingroup\$ Welcome to EE.SE, John. Answers should answer the original question, not your question. It's not clear from your answer whether you are suggesting that the OP (original poster) should try this. You should also add an explanation as to why this works. \$\endgroup\$
    – Transistor
    Commented Sep 6, 2017 at 6:11

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