Hi guys , .... I am trying to configure a Linux app to gather BMS data from all batteries (JK , Pylontech , Seplos ) and need to configure the V19 JK BMS also to talk RS485 with a Waveshare device.
Now ... for the LOVE OF GOD .... Which port is UART1 , which is UART2 and which is UART3 ?
I can see I can configure different protocols on diferent UART's but documentation of this BMS sucks and nowhere explained what is what and which port is which but they call all ports UART...

This is my "bench" setup and the JK documentation is AWFUL !!

So which port is UART1 /2 /3 ? .... im pulling my hair.. :(

I know the port I have connected now is RS485 but is it UART1 , 2 , 3 ? or what is what ?

Thanks in advance.

1. Red DIP switches – config only.

2. Green 4-pin terminal block → RS485 / CAN port (for inverters / Modbus).

3. RJ45 #1 (with yellow cable) → UART1

4. RJ45 #2 (next to it, empty) → UART2

5. RJ45 #3 (next, empty) → UART3

6. RJ45 #4 (far right, empty) → reserved / internal use (some boards label this for RS232 / debug / factory flashing).

Here’s the standard JK layout (viewing the RJ45 socket from the front, clip up):

Pin 1 (leftmost) → GND

Pin 2 → TX

Pin 3 → RX

Pin 4 → VCC (5V out, limited)

Pin 5 → NC

Pin 6 → NC

Pin 7 → NC

Pin 8 (rightmost) → NC

According to what I found until now , it should be like this :

So UART1 = RS485 ?

UART2 /RS4852 = (I can't change this in app , it changes according to DIP switches Change)

UART3 = on the PCB for Display ???