MLT-BT05 not responding to any AT commands other than just "AT"

Other Hardware Hardware Development
1

I ran this code on my HC-05 and it seemed to work, but when I replaced the HC-05 with an MLT-BT05, the only working command is "AT" and getting commands. For instance, if I type in "AT+ROLE" it replies with "+ROLE=0", but if I type in "AT+ROLE=1", it simply respond with "ERROR" with no other information. I have tried resetting it several time, checking to make sure the wiring is correct, checking and making sure the baud rate is correct, etc. I am sure it is in AT mode, given that using the basic AT command works.

#include <SoftwareSerial.h>

SoftwareSerial BTSerial(10, 11); // RX | TX

void setup()
{
  pinMode(9, OUTPUT);  // this pin will pull the HC-05 pin 34 (key pin) HIGH to switch module to AT mode
  digitalWrite(9, HIGH);
  Serial.begin(9600);
  Serial.println("Enter AT commands:");
  BTSerial.begin(9600);  // HC-05 default speed in AT command more
  Serial.println("GO");
}

void loop()
{
  // Keep reading from HC-05 and send to Arduino Serial Monitor
  if (BTSerial.available())
    Serial.write(BTSerial.read());

  // Keep reading from Arduino Serial Monitor and send to HC-05
  if (Serial.available())
    BTSerial.write(Serial.read());
}

Thank you!

2

Are you strictly obeying the instructions in the MLT-BT05 operating manual? Check the line ending setting in the serial monitor.

（AT commands ARE case sensitive; end lines with \r\n）

3

I have NL and CR enabled, which should allow it to work. On the HC-05, which had the same rule, it worked. Thank you for the response!

4

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