Does anyone have experience with drip feeding on a Meldas M50 control?

I set my machine to TAPE mode and hit cycle start, then i set my dnc program (DNC4U) to send.

it read about 10 block ok, than the machine stops.
it looks like a rts or xon xoff problem.
need some help, who has a parameter list what everything means.

btw, file transfer with in and output goes ok