VB.Net Comms problem

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  • Tym

    #1

    VB.Net Comms problem

    Not sure this is the right group - but here goes.

    I kinda expect Dick Grier to jump in on this one ;-)

    I've got a windows app in VB.Net 2005 which sends and receives text messages
    via a USM GSM modem. THe app cycles to poll the modem for incoming SMS as
    well as pausing this cycle to send...

    Working absolutely fine... except....

    After a given period of time, the app "looses" the GSM modem, and gets stuck
    on the .write command when I'm trying my AT+CSQ command. If I re-run the app
    it says the device isn't working properly.

    BUT

    I've I go to control panel, Phone and modem options, Modems - right click -
    properties - diagnostics and query the modem - all is well. After this, my
    app sees the modem fina again.

    I'm using the serialport1 control and talking to com13 in this isntance.

    How can I keep the port alive? what is happening?

    Secondly, I have connected an olf moble phone the the PC via a cable. This
    puts it on COM14. I can query this in hypertermian by selecting the port and
    issuing AT+CSQ, and getting a response. However, if I try it in my ap -
    CAM14 doesn't respond? What's the difference between Hyperterminal talking
    to the port and VB.Net?? my VB6 app can send and receive to this port (or so
    it seems to - sending AT+CMGF=1 results in an error code - in VB.NEt it
    doesn't give a code at all. However, with exactly the same code, VB.NET does
    responde to the USB on COM13 -

    Tym


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