Problem with chatscripts (in Motorola G18 GSM/GPRS) - PPP

This is a discussion on Problem with chatscripts (in Motorola G18 GSM/GPRS) - PPP ; Hello (First of all, lot of thanks again to Bill and Clifford for pointing me out how to use chat alone.) I have tested chat scripts with some mobiles (through a serial cable) and all have responded perfectly to my ...

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Thread: Problem with chatscripts (in Motorola G18 GSM/GPRS)

  1. Problem with chatscripts (in Motorola G18 GSM/GPRS)

    Hello

    (First of all, lot of thanks again to Bill and Clifford for pointing
    me out how to use chat alone.)

    I have tested chat scripts with some mobiles (through a serial cable)
    and all have responded perfectly to my commands... excepts the one I
    need, the Motorola G18 GSM/GPRS (an embedded module).

    The problem is that the phone doesn't respond most of my commands, but
    I know the commands reach him because if I make a ATD"telephone
    number" it makes the call (of course, this command has to be the first
    because it doesn't reply the previous one).

    I guessed it is a configuration problem that can be solved with a
    inicial appropiate sequence of AT commands, but I have not found these
    sequence.

    If I test with:

    chat -vs ABORT BUSY ABORT ERROR "" \
    "AT V1 E1 Q0" OK \
    AT OK \\c >/dev/ttyS0
    I sometimes get:

    send (AT V1 E1 Q0^M)
    expect(OK)


    OK
    -got it

    send (AT^M)
    expect (OK)

    alarm
    Failed


    responding to the first command but not the second (a simple AT)

    Most of the times the modem respond to none of them.

    Could any give me any idea of what the cause of so a frustrating
    behaivor could be?

    (I have used tip to try to give commands with this result: sometimes
    the mobile respond to the commands, sometimes no.)


    (It there is another group (or mail list) more appropiate for this
    question, I would be glad to know.)

    Sorry for my english and thanks for taking advantage of your
    experience


    Jorge

  2. Re: Problem with chatscripts (in Motorola G18 GSM/GPRS)

    Jorge writes:
    > (I have used tip to try to give commands with this result: sometimes
    > the mobile respond to the commands, sometimes no.)


    That seems rather more definitive. The mobile unit itself isn't
    reliable. This isn't a problem with chat.

    Some things to look into:

    - are the cables actually correct? Are there any
    intermittents anywhere? (e.g.; broken ground wire)

    - are you sending CR (hex 0D) or LF (hex 0A) to the modem?
    Some modems are sensitive to this, and will respond
    correctly to one but not the other. (Using 'AT\r\c' or
    'AT\n\c' instead of just 'AT' as the command would be one
    way to go about testing this.)

    - how is the serial port itself configured? 'chat' doesn't do
    much with stty settings, and if the settings are botched,
    you'll get very strange and hard-to-reproduce problems.

    - have you tried different bit rates? Is it more or less
    reliable at a higher or lower speed? It's possible that the
    serial port is just set to a speed the modem can't support.

    - read the modem's reference manual carefully; there may be
    special options required to set up flow control or other
    features.

    --
    James Carlson, IP Systems Group
    Sun Microsystems / 1 Network Drive 71.234W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.497N Fax +1 781 442 1677

  3. Re: Problem with chatscripts (in Motorola G18 GSM/GPRS)

    On 05 Jan 2004 07:31:46 -0500, James Carlson
    wrote:

    >That seems rather more definitive. The mobile unit itself isn't
    >reliable. This isn't a problem with chat.
    >
    >Some things to look into:


    Lot of thanks, James.
    In fact my problem was so stupid I have to write here:

    -I had (but i didnt know it) a console attached to /dev/ttyS0
    So, when activated the echo of the modem (ATE1) and i sent, for
    example, AT, the modem responds OK, so the console reply #OK, the
    modem responds #OK because his echo and so on...

    This is why I got so many #...

    Very stupid....



    Thanks again




    Jorge

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