[SOLVED] How to start Brymen BM869s in serial mode?

[JarnoKai]

How do you start the brymen bm869s in serial mode?
Mine just arrived yesterday and I am trying to test out a custom USB cable for it, but I have been scouring the internet for about an hour to find the button combination that enables it, with absolutely no luck.
I already found dozens of forum posts and articles about custom cables, protocol sniffing, sigrok problems but absolutely nothing seems to mention the button to turn it on!
Is it always on? I see that the BM251 needs you to press the "hold" button while turning the meter on - for me this simply freezes the screen until I let go of it, just like Rec and Crest. The other three buttons activate their own functions (APO, Beep, weird diagnostic code)

[2N3055]

There is nothing to do on the meter. Plug in the original cable, start the software from Brymen and it works.
It is not a serial protocol, it is USB device, there is no serial port emulation...

For custom cables and custom converters you need to follow it's instructions..