Posts by Ben

    Question:
    How they can switch off the SMS return/acknoledgement
    on the GM862-GPRS from the SMS centre?


    Answer:
    You can do this when you send SMS in PDU mode, simply setting the correct flag in the PDU message.


    Otherwise, you can do this when you send SMS in TEXT mode, simply by setting the correct flag in the TEXT mode
    parameters command.
    e.g. AT+CSMP=17,0,0,0



    - Editiert von Ben am 05.05.2003, 22:05 -

    Question:
    1. Is it possible to receive SMS directly without writing to SIM card`s
    memory? (without AT+CMGR & AT+CMGD commands)


    Answer:
    No, with AT+CMGR & AT+CMGD you can use only the SIM memory storage.
    We will include this feaure soon.


    2. Why DCS parameter is not changing ?
    Independent of CSMP settings - TP-DCS always appear as 18 ( 12 HEX ).
    We must use DCS=0.


    Answer:
    below an example of AT+CSMP use with parameter <dcs> changed (before 0
    after 2).


    at+csmp=17,167,0,0
    OK
    at+csmp?
    +CSMP: 17,167,0,0


    OK
    at+csmp=?
    +CSMP: (0-255),(0-255),(0-255),(0,2,18,240,242)


    OK
    at+csmp=17,167,0,2
    OK
    at+csmp?
    +CSMP: 17,167,0,2
    OK

    GM862-GPRS
    Our application will be that no power is applied to the modem until required.
    Will the modem be happy under these circumstances?
    What is the modem settle time and what can we expect the site registration time to be before the SMS can be sent.
    Our application is battery powered and we wish to keep the physical battery sizing to the minimum


    Answer:
    it`s ok to power the GM862-GSM only when needed, provided you don`t use the clock/alarm feature, anyway
    there`s no need to remove the power from the GM862-GSM since its consumption when turned off is few uA (typically 26uA).
    Instead we suggest that the whole application to be turned off (or better powered off) with only the GM862-GSM powered but shut down, with its alarm set in order to periodically wake-up itself and the controlling application and proceed with SMS sending if required (if you need that feature as we see).
    You can see an example of this application in the Software User Guide under the alarm example section.

    About the other question, its hard to give a typical time to be ready to send an SMS, since it depends on network condition on the site and may vary greatly. As a thumb rule, if the GSM modem remains in the same position and therefore with the same network cell to register to and the signal strenght is good, the registration time will be quite short and may be around 30s.

    Question:


    How can I upgrade the software?
    I am using the GM862-GPRS with the RS-EB-S1 board.


    Answer:
    Please contact Round Solutions and you will receive the flash program.


    After that you do the following:


    1) Com Port 1 am PC
    Com Port 1 to use 57600 kbs, data bit 8, parity none, stop bit 1, flwo control: hardware

    2) Start MFP_GM862G.exe file.

    3) Klick only one CS851

    4) Power up the GM862-GPRS

    5) Click on start on the pc program and hold pin 10 on the S1 board on
    ground for 2-3 seconds.

    Hello!
    We have built a GM862 GPRS Module-deployed Voice, FAX, Data, GPRS system (I`ll
    call it GSM FAX from now on for my convenience.)



    Question 1: for AT Commands used in modem.
    As I know, the return value for the question "Report model ID
    AT+FMM?" should be "GM862-GPRS-GSM900/1800 voice/data/fax OK". But for now
    it returns only "GM862-GPRS-GSM900/1800 voice/data OK" That means it do not
    show `fax` in the return value. Does it mean that the module does not
    support Fax? Surely, there are descriptions in the data sheet that it
    supports FAX. Could you explain about it in detail for me?


    Answer:
    The FAX feature is actually supported in the GM862-GPRS, we didn`t report it
    in the ID, but this is not mandatory since the ID is only supposed to show
    the model name, not its features. To check whether the FAX is implemented
    you shall check the AT+FCLASS value that must support value 1-Fax class1
    service.


    Question 2:
    I`d like to know what purpose the commands "Signaling Tones Mode AT#STM" and
    "set Handsfree side tone AT#SHFSD" are respectively used for, and how the
    developers can get the result?


    Answer:
    The signalling tones enable/disable applies to the tones usually played on
    particular events such as call established tone, call dropped tone, call
    ended tone, network registration loss, network registration regain, battery
    low (if power supply goes below a certain threshold) etc.. For some
    applications these signalling tones might be unwanted and therefore they can
    be enabled/disabled with the #STM command.
    About the Handsfree side tone: the side tone is a sort of local echo of the
    microphone signal that is reported on the earpeace, this is always required
    when the voice call is made by human beings (yust to let the speaker hear
    what he is talking about), but it might be disturbing when the voice call is
    managed by a machine.Therefore it is possible to enable/disable it with the
    #SHFSD command.



    Question 3: The biggest problems are occurred when I tested to send a fax message from
    a system with a Fax connected to another system also with a Fax connected.
    i - Problem occurred when sending the fax from PSTN FAX to GSM FAX
    When sending fax from PSTN FAX to GSM FAX, if I check the RING incoming to
    GSM FAX, the ring comes as "+CRING: VOICE". It should come as "+CRING: FAX".
    Shouldn`t it?


    Answer:
    Yes of course, here the problem is not due to a wrong behaviour of the
    module, but actually is due to the PSTN that has not requested a FAX call
    on the GSM network and therefore the GSM network reports the call incoming
    from the PSTN as the default VOICE service. This occurs especially when the
    call is issued through a not configured ISDN PABX.
    Note that if the PSTN number calling is analog (not ISDN) and its service is
    promisquous (voice/data/fax depending from the device which issued the
    call), the GSM network has no means of recognizing the service you are
    requiring and therefore it chooses the default voice. Once the call incomes
    with a VOICE signature, then there`s no means for any GSM device to answer
    it as FAX since it has different network protocols. Usually to overcome this
    problem the Network Operator gives to a Voice/Data/Fax enabled SIM three
    different numbers, one for outcoming/incoming VOICE service, one for the
    incoming DATA calls and one for the incoming FAX calls. In this case you
    must call the right number and the call will be forwarded by the network as
    the requested service.



    As a general comment, everything is explained in the FAX class 1
    operation specification by ITU-T T.31, other information on Fax service is
    contained in the ITU-T T.4 e T.30 specifications. Refer to these for FAX
    class 1 operation.

    Question 1:
    AT+COPS and AT+CSQ show a valid GPRS network assignment and a high signal
    level. However, AT+CGDCONT often results in "CME ERROR". There seems to be
    no way to find out what exactly went wrong.


    Answer:
    What happens is that you are trying to register the GPRS context (AT+CGDCONT) while the mobile has done its GSM registration procedure but has not yet ended the GPRS registration. Therefore the mobile is reporting the GSM registration values but it`s not yet ready for GPRS. Simply retry after few seconds and it should register the context correctly. Or better allow some 10 seconds between the +CPIN and the context request, just to allow the mobile to register.


    Question 2:
    After ATD we get "CONNECT" and switch to PPP mode. Everything works fine:
    - we do LCP negotioation (ConfReq and ConfAck)
    - we start PAP authentication (PAP AuthReq)
    Now the modem says in the AuthAck result:
    "Telit PPP in progress"
    and ppp receives a hangup from the modem (modem probably resets modem lines)


    Answer:
    What happens here is a peculiar behaviour of the GPRS devices: the GPRS modem responds immediately CONNECT and switches to PPP mode, gathering from you all the informations it needs to establish the GPRS connection. Note that the PPP is between you ( the PC104) and the GM862-GPRS. Once gathered from you the information (PAP & LCP) the modem negotiates these with the network and at this point if succeded (in your case NOT therefore it hangs up as if the call is dropped) proceeds with the NCP phase (IP configure) (this is really negotiated between you and the network) and once finished it`s ready to exchange data.


    So this is due to some PAP errors in your configuration that fail on the network side, check your USERID & PWD.



    Question 3:
    I take it the modem implements a ppp stack when communicating with the
    attached PC.
    In a successfull connection our pppd sends out LCP echo requests and always
    receives a positive answer - even with no aerial connected. There seems to
    be no way to find out wether the GPRS connection is OK.

    Answer:
    As explained, this is a particular behavior of GPRS modems, you find out that the GPRS connection is not OK when the modem hangs up.

    Question:
    In order to save the power consumption during the sleep mode, in my
    application I need to turn off the the GSM862.
    However, I would like to maintain the statue of GPIO. What should I do?
    Should I provide the backup for Main power system of the GSM862?


    Answer:
    The status of the GPIO pins is lost when the module is turned off.
    The only GPIO that differ are the GPIO6 and GPIO7 that remain in the same direction as previously set but loose the pin <mode>. This is for allowing to set the GPIO6 as alarm ouput (alternate function) and the pin is still alarm output after a power-off when the module awakes with the alarm. The same thing is for GPIO7, its direction is maintained to use it as buzzer output.


    Anyway the GPIO pin <mode> is not maintained for all GPIO pins, also GPIO6 and GPIO7.


    Also providing a backup for Main power system of the GM862-GPRS does not affect this behaviour, once shut down the status of the GPIO pins is reset.


    You can store the status of the pins somewhere else (in the controlling application?) and issue on startup the appropriate AT#GPIO commands to restore it.


    When turned off, all internal logic is shut down, except for the Real time clock.

    Question: Is the GM862-GPRS/GSM certified with BABT?


    Answer:
    Yes, all our modules are registered with BABT

    Question:
    Our application will be that no power is applied to the modem until required. Will the modem be happy under these circumstances? What is the modem settle time and what can we expect the site registration time to be before the SMS can be sent. Our application is battery powered and we wish to keep the physical battery sizing to the minimum


    Answer:
    It`s ok to power the GM862-GSM only when needed, provided you don`t use the clock/alarm feature, anyway
    there`s no need to remove the power from the GM862-GSM since its consumption when turned off is few uA (typically 26uA).
    Instead we suggest that the whole application to be turned off (or better powered off) with only the GM862-GSM powered but shut down, with its alarm set in order to periodically wake-up itself and the controlling application and proceed with SMS sending if required (if you need that feature as we see).
    You can see an example of this application in the Software User Guide under the alarm example section.

    About the other question, its hard to give a typical time to be ready to send an SMS, since it depends on network condition on the site and may vary greatly. As a thumb rule, if the GSM modem remains in the same position and therefore with the same network cell to register to and the signal strenght is good, the registration time will be quite short and may be up to around 30s.


    Answer:
    As soon as you turn on the GM you can wait 5 second if you wish and run the sequence AT+CMGS then it sends the SMS as soon as it is connected to the provider. You can try to send it directely after turning ON the GM but you have to control if it send you ERROR or OK after sending the sequence AT+CMGS and the manage to send it again until it goes through.
    - Editiert von Ben am 03.05.2003, 11:34 -

    Question:
    Can the GM862-GSM/GPRS do auto answer with a voice call or is it data calls only?


    Answer:
    The auto answer is active for both data and voice calls.

    I think I`ve found the problem. I was setting the current limit on the power
    supply to my PCB at 1 amp. When I set it to it`s maximum of 2 amps the GM862
    seems to work fine. I was aware that I had the power supply current limiting at 1
    amp but didn`t think that it mattered. Obviously I was wrong!

    Questions:
    AT+WAIP=1
    The GM862 gives an ‘error’ response to this command and as it is concatenated with a number of other commands we are not sure if subsequent commands in the string are ignored.


    Answer:
    This is a Wavecom propriatary command and should result in an error message from all other GSM modules as well.
    If you place it as last in the command of the string, you`ll obtain anyway the OK and the modem is skipping the rest of the command.
    Since the phone book is empty it should not make any difference in practice.


    Question:
    AT+CFUN=0
    This command is used by our unit to power down the modem ‘gracefully’ allowing de-registration form the network etc.
    The GM862 gives an ‘error’ response to this command and does not power down.


    Answer:
    If you just need to power off the module then change the command to AT#SHDN


    Question:
    AT&F followed by CBST=71,0,1 and other commands concatenated in the same string.
    This command sets to factory defaults and then sets specific parameters as required by our application.
    The GM862 comes out of this string of commands in factory default mode, ignoring all other settings.


    Answer:
    We have checked and the AT&F+CBST=xx,xx,xx string is working fine.
    First sets the factory default and then the value for CBST.
    You might be using AT&F;+CBST=xx,xx,xx which is not working (not correct command).
    After the at&f.. no ; must be placed before the + sign of the extended commands.


    E.g: AT&F+CNMI=2,1,2,2,0;+CBST=71 is a correct string
    AT&F+CBST=71 is a correct string


    AT&F;+CNMI=2,1,2,2,0;+CBST=71 is a wrong string
    AT&F+CNMI=2,1,2,2,0+CBST=71 is a wrong string

    Questions:
    AT+WAIP=1
    The GM862 gives an ‘error’ response to this command and as it is concatenated with a number of other commands we are not sure if subsequent commands in the string are ignored.


    Answer:
    This is a Wavecom propriatary command and should result in an error message from all other GSM modules as well.
    If you place it as last in the command of the string, you`ll obtain anyway the OK and the modem is skipping the rest of the command.
    Since the phone book is empty it should not make any difference in practice.


    Question:
    AT+CFUN=0
    This command is used by our unit to power down the modem ‘gracefully’ allowing de-registration form the network etc.
    The GM862 gives an ‘error’ response to this command and does not power down.


    Answer:
    If you just need to power off the module then change the command to AT#SHDN


    Question:
    AT&F followed by CBST=71,0,1 and other commands concatenated in the same string.
    This command sets to factory defaults and then sets specific parameters as required by our application.
    The GM862 comes out of this string of commands in factory default mode, ignoring all other settings.


    Answer:
    We have checked and the AT&F+CBST=xx,xx,xx string is working fine.
    First sets the factory default and then the value for CBST.
    You might be using AT&F;+CBST=xx,xx,xx which is not working (not correct command).
    After the at&f.. no ; must be placed before the + sign of the extended commands.

    E.g: AT&F+CNMI=2,1,2,2,0;+CBST=71 is a correct string
    AT&F+CBST=71 is a correct string

    AT&F;+CNMI=2,1,2,2,0;+CBST=71 is a wrong string
    AT&F+CNMI=2,1,2,2,0+CBST=71 is a wrong string



    - Editiert von Ben am 05.05.2003, 22:03 -