#10 Problem with sending data to multiple COMports using hub4com


I am trying to set up a configuration for testing changes to an existing program. I want to use my simulation program in both the original and the updated program. I used .\com0com\setupg.exe to create the necessary COM Ports: COM15 <-> CNCB0, COM11 <-> CNCB1, and COM13 <-> CNCB2. The original uses another simulation program on COM pair COM12 <-> COM16 (This one is functioning just fine).

To receive the messages from my simulation software on both (VB6) programs I installed a hub4com using the following statement:
hub4com.exe" \\.\CNCB0 \\.\CNCB1 \\.\CNCB2

This configuration functions fine with HyperTerminal.
Everything sent by my simulation software into COM15 is received simultaneously on both COM11 and COM13.
Now, when I disconnect both COM Ports and hook up my own VB6 programs, the data does not seem to become available on the MSCOMM object.
(I am polling MSCOMM on a Timer Events, checking MSCOMM.InBufferCount to see if there is any data available for processing)

When I stop debugging and restart HyperTerminal, the data is immediately available when I reconnect to COM11 and COM13.
Is there anything wrong with my configuration?
Do I need any hardware signals, or are they lost using hub4com?
I could do with some hints on hub4com...

(By the way, communication does function when I am using "real" COM Ports or USB to Serial convertors. The same goes for a COM Pair defined using com0com. Therefore I expect the problem has got something to do with hub4com)


  • Robbedoes

    Robbedoes - 2010-04-19

    I noticed a typo in the configuration statement for hub4com.
    I don't know how to fix it in my post, so I will just add a comment...

    The actual statement I used is as follows:
    hub4com.exe \\.\CNCB0 \\.\CNCB1 \\.\CNCB2

  • Vyacheslav Frolov

    • status: open --> pending
  • Vyacheslav Frolov

    By default hub4com use CTS handshaking on output so if CTS state is OFF
    then no any data can be sent to the port. To disable CTS handshaking add
    --octs=off option.

    For more info see

    hub4com.exe --help=serial

  • Robbedoes

    Robbedoes - 2010-04-20
    • status: pending --> open
  • Robbedoes

    Robbedoes - 2010-04-20

    Thank you VFrolov!
    That did the trick!
    Happy Comm-ing!

  • Vyacheslav Frolov

    • status: open --> closed

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