Since I used An Alva Satellite product, I found, that the best solution is NVDA and properly configured brltty version 4.x not 5. When I tried to use a protocol converter, NVDA said "could not load a BC6 display."
I recommend you to buy a power cable and if you have not serial port on your computer, buy a usb to serial converter and use brltty.
p.s. if anyone find a solution on how to use a protocol converter with NVDA it will be very appretiated.