Serial control with Kincony K868-A4?

ESPHome
1

Hi

First time trying to use serial control with HA (have done it for years with antic automation system like AMX, Crestron ones) but I struggle to get it working with HA and ESPHome.
I’m using the Kincony K868-A4 box ARDUINO ESP32 4 CHANNEL RELAY MODULE – KC868-A4 to get a serial port.
I have tried wiring serial port between kincony and device controlled straight or crossed but not better ! (product was controlled previously without problems by a Crestron system).
Here is code used in ESPHome:

substitutions:
  friendly_name: esp-tr-02

esphome:
  name: $friendly_name
  platform: ESP32
  board: esp32dev

logger:

web_server:

ota:

wifi:
  networks:
  - ssid: !secret wifi_ssid
    password: !secret wifi_passwd
  manual_ip:
    static_ip: 172.16.2.81
    gateway: 172.16.1.1
    subnet: 255.255.252.0
  ap:
    ssid: $friendly_name

captive_portal:

api:
  reboot_timeout: 10min
#  services:
#    - service: volume
#      variables:
#        volume: Int
#      then:
#        - uart.write: !lambda
#            return {0x00, 0x20, 0x42};

sensor:
  - platform: uptime
    name: $friendly_name Uptime
    filters:
      - lambda: return x / 60.0 /60.0;
    unit_of_measurement: hours
  - platform: wifi_signal
    name: $friendly_name WiFi Signal
    update_interval: 60s

button:
  - platform: template
    name: CD Input
    on_press:
      - uart.write: "CD\r"
  - platform: template
    name: DVD Input
    on_press:
      - uart.write: "DV\r"

uart:
  tx_pin: GPIO17
  rx_pin: GPIO16
  baud_rate: 9600
  debug:

Protocol of the device I try to control: Domedia NextCloud

Any ideas what’s wrong here ?

Thanks

Vincèn