RS485 api for Home assistant

Hi

I have a Danish home automation system that is limited to their own items, but they will soon open for port RS485 communication and supply the API, it would be nice if possible to use other smart home products, does anyone wit programing skills know if it would be possible to make a program for raspberry hub ore similar to handle communication between the two systems ?

Home Assistant already supports a large number of devices that support RS485/modbus, so if you have the API you could command it through HASS.

Thanks for reply !
What do i need for it to work, do i have to get some kind off gateway based on program on raspery gateway ore is there something plug and play ?

I used a $2 usb to rs485 usb stick.

Yes but did you put the adapter in raspery to convert signal, ore hov do the two systems cumunicate ?

Yes, I put it in the USB port. Connected the A and B wires of the converter to the devices and that was it.

Hi, can you give me an example how can I listen a device connected to my USB RS485 connected in one Raspberry 4+ USB port ?
this is my hardware on USB port : - /dev/serial/by-id/usb-1a86_USB2.0-Serial-if00-port0
connect A / B to Carlo Gavazzi Energy-meter

my configuration.yaml :
modbus:
name: hub1
type: serial
method: rtu
port: /dev/serial/by-id/usb-1a86_USB2.0-Serial-if00-port0
baudrate: 9600
stopbits: 1
bytesize: 8
parity: N

This will listen https://www.home-assistant.io/integrations/serial/