When I use this I do:
for 2400 baud

DEFINE SER2_BITS 8

pinin VAR PORTC.7
pinout VAR PORTC.6

SerOut2 pinout,396,[B1]

SerIn2 pinin,396,[B1]

or

SerIn2 pinin,396,50,verdr,[WAIT ("X"),B1]

depents on the application look at page 132(5.72) and further.

And in the pc I programm in qbasic(7.1)

and this works always.