Comm Set TxBuffer/RxBuffer problem

[Ketil Krumm]

More strange serial comms issues... I still have the NT WS 4 SP 6A with a Digi AccelePOrt 8r 920 8-port card fitted. COM1 and COM2 are the usual built-in ports, the ports on the card are numbered COM3 thorugh COM10.

Here's the code, very straightforward:

    hComm = FreeFile
    Comm Open "COM1" As #hComm
    If ErrClear Then Function = %FALSE: Exit Function
 
    Comm Set #hComm, Baud = 9600
    Comm Set #hComm, Byte = 8
    Comm Set #hComm, Parity = %FALSE
    Comm Set #hComm, Stop = 0
    Comm Set #hComm, DtrLine = %TRUE
    Comm Set #hComm, TxBuffer = 1024
    Comm Set #hComm, RxBuffer = 16384
 
    MsgBox Format$(Comm(#hComm, TxBuffer)) & " - " & _
           Format$(Comm(#hComm, RxBuffer))

Default values are 0 and 4096 for TxBuffer and RxBuffer, respectively - at least that's what I get if I comment out the two lines. The code sample above displays a message box with the text 0 - 16384. In other words, the RxBuffer has been set, but not the TxBuffer.

Changing the Comm Open statement to use COM3 instead (first port on the AccelePort card) displays 4095 - 10239 regardless of whether the RxBuffer/TxBuffer statements are executed or not.

Can anyone of you gurus out there make any sense of this??

Thanks,
Ketil