Hi,
Software UART:

Dim A As String * 10

Open "COMD.3:9600,8,N,1" For Output As #1 'RAUS
Print #1 , "HALLO"

Open "COMD.4:9600,8,N,1" For Input As #2 'REIN
Input #2 , A



findest du in der Hilfe unter dem Stichwort "OPEN"

Gruß
Christopher