trouble with Uart connection 16/17 via hardware serial

[treii28]

I have a voice recognition module from Veeer (EasyVR v3) and when I connect it to the PC, I get a 95% or above recognition rate. As soon as I connect it to the ESP32 (via hardware serial on pins 16 and 17) I am only getting about 20-30% recognition rate. I've already sent a message off to their support for suggestions, but most of their coding appears to be done on a standard arduino, so I figured I would ask here as well.

I'm wondering if there are any things I can do to trouble-shoot why it would seem to be having a difficult time when connected to the ESP32. Maybe a need for pull-up resistors or issues with other electronic noise? Any suggestions are welcome.

I'm using a Wemos D1 mini ESP32 clone with an ESP-32S chip. I also have a i2s DAC (on DAC1/DAC2 pins), SD card adapter (on standard SPI pins) and a PCA9685 PWM expander on the standard I2C bus pins.

I'm powering the EasyVR from the 5v vcc pin, using 16 as rx, 17 as tx via the second hardware serial (Serial1).

Any assistance, suggestions or help troubleshooting this problem is appreciated!

SW

[costaud]

I have a voice recognition module from Veeer (EasyVR v3) and when I connect it to the PC, I get a 95% or above recognition rate. As soon as I connect it to the ESP32 (via hardware serial on pins 16 and 17) I am only getting about 20-30% recognition rate. I've already sent a message off to their support for suggestions, but most of their coding appears to be done on a standard arduino, so I figured I would ask here as well.

I'm not sure how the voice module works.
Does it send something to UART when it recognises some voice ? If so, I would first try to figure out whether the UART data are ignored by esp32 for some reason or the voice module didn't send out that data at all.