Bluetooth LE UART and Bluetooth 3 different results on serial output

Question

let me first explain the situation. So I have a Bluetooth v3 module connected to a serial port of a motor, this motor is controlled over a android app using the connection to the BT3 module.

Now I would like to migrate this to a BT 4.2 module and use Bluetooth LE to send the data. But here is the problem. The data that is received on the serial port over the BT3 and BT LE differ slightly.

The difference example: sent string "hello world" converted to bytes and sent

• result to the motor from BT LE would be: "hello world"
• result to the motor from BT 3 would be: "heLl` world"

at first I suspected some custom bound rate on the BT 3 module, but according to the documentation I got along the motor and the BT 3 module are also set to 19200. So I am stuck at what would cause this difference on the serial output of the modules.

both BT modules: Bound rate: 19200 Stop bits: 1 Data bits: 8 Parity: none

BT3 is unknown (the data stickers have been removed, but this device currently does control the motor successfully) BT LE is rn4780 module

Answer 1

Considering that the motor recognizes both signals from both modules, my suspicion is that the serial to USB converter has problems with the bluetooth classic module and that it's the fault for the data corruption occurring in the test environment.