tomcon
13
Hi Leenve,
sorry for the delay. Had have some digital detox 
Get the Firmware (PR55-61N_V4.zip) from here
The Step by Step Description is here
May be my other Thread will help a little bit more with the molex connector layout.
I’ve used this Serial USB Connector
https://www.amazon.de/gp/product/B0773G2K92/ref=ppx_yo_dt_b_asin_title_o01_s03
But remember : also make sure Tx and Rx are cross wired.
– Tom