DMX on UART 0 / vs UART1

I am quite new to the ESP8266 so maybe somebody an shine a light. I am trying to get DMS output working on a H803 module, which has the DMX TX pin on ESP U0TXD (GPIO1)

I configured the DMA output pin to 1 and observed it on a scope. I see 1.3ms pulses with an interval of approx. 28ms. Every 15 pulses some of them look more like data, but nothing looks like the 4us bit time of DMX. I wondered if it is possible that DMX uses UART1 while I am using a UART0 pin.

When looking into the DMA code I find the baudrate being set to ‘serial1’ which a is HardwareSerial instance. Hardware serial expects the UART number in the constrcutor, but I cannot find where this is done.

Anyone who can clarify the DMX serial vs UART for me ?

I can answer my own question here. For some reason VS code showed the text “software uart” when hovering over “Serial” (without the 1), so I did not expect this to be Hardware UART0.
After some digging I found information that just “Serial” maps to UART0, so changed the code and now the DMX data was output to the correct UART for the H803WF module.