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Transferring state to DCD,RING,DSR, CTS

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Anonymous
2011-06-21
2013-05-20
  • Anonymous

    Anonymous - 2011-06-21

    Hi,
       The Readme suggests reading example at:

       http://com0com.sourceforge.net/examples/MODEM_CONTROL/tstser.cpp

    to know more about transferring state to DCD, RING ,DSR and CTS. DSR and CTS are wired to RTS and DTR so that is relatively simple. However, I have problems understanding the code that handles transferring of state to DCD and RING. Would it be possible for you to add some comments/documentation to the code that makes it easier to understand? How does extending IOCTL_SERIAL_SET_MODEM_CONTROL and IOCTL_SERIAL_GET_MODEM_CONTROL work? Thanks.

     
  • Anonymous

    Anonymous - 2011-06-21

    Also, is there a way I can get access to the file cntext.h? If not, there are certain macros used in the above mentioned link. If I could know what their, values are that would be helpful too. Thanks

     
  • Anonymous

    Anonymous - 2011-06-28

    Hi, is there anybody who has tried this(transferring state to DCD,RING,DSR,CTS) before ? I think I understand most of the code in  http://com0com.sourceforge.net/examples/MODEM_CONTROL/tstser.cpp. However, some questions remain:

    1. In CTL_CODE what do function code 37 and 38 stand for? i tried searching around but couldn't come up with a definite answer.

    2. Why is comparing the size of the output buffer and variable that receives the size of the data stored in the output buffer enough to make sure that ShowModemControl works(IsExtended also works the same way)?

     
  • Vyacheslav Frolov

    The hub4com is the second example of usage of extended functions IOCTL_SERIAL_xET_MODEM_CONTROL.

    The standard functions IOCTL_SERIAL_GET_MODEM_CONTROL(37) and IOCTL_SERIAL_SET_MODEM_CONTROL(38) are described here:

    http://msdn.microsoft.com/en-us/library/ff546748%28v=vs.85%29.aspx

    The comparing the size is enough for standard functionality (ShowModemControl). The comparing the signature is enough for extended functionality (IsExtended).

     

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