[BRLTTY] Braille Lite 40 doesn't work correctly

[Sebastian Humenda]

Hello,

I have here a Braille Lite 40 Display. It is connected on the serial port. I 
tried a while to run BRLTTY using this display, but with no success. I'm not 
shure, whether this is my false. First I started BRLTTY with
brltty -b bl -d ttyS0 -t de
Brltty made the sound that it had detected the display, but the braille lite 
40 showed no sign. I tried this a few times, then I tried to start brltty 
with driver auto detection. There appeared messages like "fun" on the 
braille display, but nothing more. I suppose that's simply a test :-). I 
heard several sounds from the bl40, certainly because BRLTTY tried to detect 
the driver type.
Later I tried the driver bl again and noticed, that the keys for entering 
braille worked. And that's the point where I have no idea. At the moment I 
can use the braille display as a keyboard, but not as a braille display.
Wat I am doing wrong?

Thanks
Sebastian