Impossible to open COM port (SPP bluetooth with ESP32)

Projects Networking, Protocols, and Devices
1

I try to collect data from an ESP32 via serial over (classic) bluetooth.
As a first step, I programmed the ESP32 for the cyclic transmission of a message on serial over bluetooth (SPP).
The messages are well received on my android phone with a serial BT terminal APP.
But when I try to receive them on my Windows-11 PC, I succeed to pair the ESP32 with the PC, but it is impossible to open the relevant COM port with a terminal (I tried several of them, including the Arduino serial monitor).
In the past, I had already succeeded to do the same with an HC-05.
What are the specific pitfalls with the ESP32?

2

problem confirmed!
on Win11 it connects to "ESP32-0BT-Slave" then a second or so later disconnects and shows

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maybe a Windows 11 problem
can connect with Android phone and in the past have connected OK using Windows 10

will boot up a windows 10 pc and try it

EDIT: tested with Windows 10 and can pair with ESP32 and transfer data

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two virtual COM ports are created
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teraterm terminal emulator connects to COM29 and transfers data to/from the ESP32

3

I also just had the chance to put hands on an older Win10 laptop.
It pairs with the ESP32, and then a serial terminal connects without any problem and displays the cyclic messages.
It obviously looks like a Windows 11 specific problem.

If anybody found a workaround, I would really be glad to read about it.

4

it appears to be a known problem - see Serial over (classic) bluetooth / COM port can't be open with Windows 11

try BLE UART?

5

I just rolled back my Arduino ESP32 board support package (BSP) version from 3.3.3 to 1.0.4
The rest of the configuration is the same (Windows 11, Arduino IDE 2.3.6, Wemos D1 R32 board).
There is no more problem: the COM port opens well and the transmission is perfect.
Hence it's not a exactly Windows 11 problem but a compatibility issue between ESP32 with its latest BSP version and Windows 11.

It would be great if espressif could take a look on this issue.

6

At PC side, I need to communicate with the HC-05 via a COM port.
Do you manage to make a virtual COM port for this?

7

maybe simpler to get a USB Bluetooth dongle - make sure it is the version of bluetoth you require