Lab
Factory baud rates by module
The web is confidently wrong about this. The usual wrong answer is that everything is 9600 for everything — which is right for data on most modules and wrong for AT commands on an HC-05, where the factory default is 38400.
Serial1.begin() and the Serial Monitor must both be set to.AT+UART run on it keeps the rate it was given — the table tells you where to start, not what your board is set to today.What this shows
HC-05: 9600 for data, 38400 for AT commands. Many ZS-040 clones ship at 38400 for data as well.
HC-06: 9600, with no separate command mode — the same rate works for both.
HM-10 (genuine): 9600, rising to 115200 on firmware V700 and later. AT commands use the same rate as data.
CC41-A and MLT-BT05: 9600 for both. These are HM-10 clones and use a different AT command syntax from the genuine part.
57600 is not the factory default for anything on this list, despite appearing in widely viewed tutorials. A guide recommending it is describing a module somebody had already reconfigured. It is also the one rate a 16 MHz Arduino generates badly, at 2.12% error against 0.16% for 9600.
Common questions
- What is the default baud rate of an HC-06?
- 9600, for everything. Unlike the HC-05 it has no separate AT command mode, so the same rate works for both data and configuration.
- Is 57600 the right baud rate for a Bluetooth module?
- No. It is not the factory default for the HC-05, HC-06, HM-10 or the CC41-A clones, although it appears in tutorials with large view counts. Those describe a module that had already been reconfigured.
- Why does my HM-10 use 115200 instead of 9600?
- Genuine HM-10 modules running firmware V700 and later default to 115200. Earlier firmware, and the CC41-A and MLT-BT05 clones, default to 9600.