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Comm Set TxBuffer/RxBuffer problem

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  • Comm Set TxBuffer/RxBuffer problem

    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??