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Problem dialing using a phone card

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  • Problem dialing using a phone card

    I am trying to use a phone card to dial from my modem. The number that I dial
    is fairly long... with the access number, PIN number, and the number of commas
    required for pauses.

    For some reason that I don't understand, the modem won't dial when the number
    is longer than about 37 characters. I have tried larger RX and TX buffers, but
    to no avail. Does anyone have an idea of what my problem might be?

    I am using the following values in my code.

    hComm = FREEFILE
    commPort = "COM" + TRIM$(STR$(commPortNo))
    COMM OPEN commPort AS #hComm
    COMM SET #hComm, BAUD = 9600
    COMM SET #hComm, BYTE = 8
    COMM SET #hComm, STOP = 0
    COMM SET #hComm, RXBUFFER = 8192 '1024
    COMM SET #hComm, TXBUFFER = 8192 '1024

    COMM SEND #hComm, "ATDT" + dialNumber + ";" + $CR


  • #2
    Could be a limitation of the modem itself. If they don't mention in the modem
    docs, you might check with the manufacturer.

    Make sure you trim out any unnecessary characters from the dial string:
    spaces, dashes, parentheses and whatnot are fine for display purposes, but
    the modem doesn't need to see them.

    Tom Hanlin
    PowerBASIC Staff


    • #3

      I'm not sure about all modems but I remember when I was running IT helpdesk in Sydney for AT&T some users complained that they couldn't use their AT&T Calling Card and it turned out that some types of the Xircom modems being used did indeed have a digit limit that was as I recall around 40 or so. These modems had to be swapped for users of the calling card. It's wouldn't surprise me to find out that some other modem manufacturers had similar limitations. I haven't seen the problem on any of the new modems if you check the web site you might find something. Try searching the web for "digit limitation of BRANDXXX modem" or something, that's how we eventually found it


      Paul Dwyer
      Network Engineer
      Aussie in Tokyo
      (Paul282 at VB-World)


      • #4
        Agreed... I've seen the same behavior too.

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