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  1. #1
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    Question how to establish data call ??

    i want to send at command from pic to the GSM modem for establish data call .
    what command i need to establish the data call over GPRS??
    and if any one work in this subject ,i ask him to provide me the code for this service.
    thanks alot

  2. #2
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    Default Re: how to establish data call ??

    It is not that simple.

    You need to setup the GPRS modem according to its specific AT commands. Either on a terminal or through your PIC controller.

    Then you have to open a "channel" to a Static IP address since the Mobile Network ususally provides Dynamic IPs.

    Because I founded a bit difficult, I preffered the solution of a ready GPRS bridge to Serial: the WirelessCOM from Teltonika (www.teltonika.com).

    You only have to set up easily through a Terminal and then whenever you write even a single byte on the serial port, it establishes automatically a connection to the programmed IP and sends the data. Like Serial to serial communication.

    Ioannis

  3. #3
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    Default Re: how to establish data call ??

    thanks for replay
    u have code for that service ??
    and how this service work ???
    i try to do some code
    but the result always no carrier

  4. #4
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    Default Re: how to establish data call ??

    no one know the at command for this service ??

  5. #5
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    Default Re: how to establish data call ??

    I think I told you that it is totally dependant on the model of your device.

    Read your device manual or data sheet and see what commands it needs.

    Ioannis

  6. #6
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    Default Re: how to establish data call ??

    Hi Ioannis,

    The Telonika WirelessCom sounds ideal for an application I have in mind. I Just skimmed through the manual for it and found it a bit sketchy in parts. I assume that if you have the static IP address for your internet-connected PC then the rest is straightforward. Did you find any traps in configuring the unit?

    Thanks

    John

  7. #7
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    Default Re: how to establish data call ??

    Hi John.

    In general is very easy to set it up.

    The only trap was the buffer, that was factory set up to a very large number, I think 2 or 4000 bytes.

    So my initial attempts to send a few "hello" to the host,just seemed to fail. But the problem was that buffer did not filled up with data, so no connection was made. I had to send a few thousands of bytes to see them coming, but was not aware of that.

    After changing the buffer size,all was working great. And fast really. I received my data in less than a second!

    Ioannis

  8. #8
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    Default Re: how to establish data call ??

    i find the AT command for my GSM/GPRS modem
    i don't know which command to be used for establish the data call
    can i connect 2 GSM/GPRS modem to send data over GPRS?
    here the AT command for my GSM/GPRS modem Telit GE865-QUAD
    http://www.edaboard.com/attachments/..._r5%5B1%5D-pdf
    what's the code for establish this connection between the modems ??
    thanx

  9. #9
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    Default Re: how to establish data call ??

    A "data call" is not correct.

    By data call I suppose you do not mean a 9600, modem connection, right? This is different story. Just get a data/fax service from your provider (usually a new data/fax number on the same SIM card) and you have it already done!

    The GPRS is totally different thing. You need all the parameters from your provider (APN, username, password, type (PAP,CHAP,Auto) and maybe others).

    Also you cannot establish point to point communication since the IP of the GPRS service is dynamic.So you need to establish a communication to a Static IP, usually a PC running some server software to relay data to another GPRS device.

    Ioannis

  10. #10
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    Smile Re: how to establish data call ??

    iam try this command for data call on CSD
    AT
    OK
    AT+FCLASS=0 ----->to set the data mode
    OK
    AT+CBST?
    +CBST: 0,0,1

    OK
    AT+CBST= 1,0,1;------>here i changed the speed
    OK
    at+cbst?
    +CBST: 1,0,1

    OK
    atd 0599592724
    NO CARRIER

    the result no carrier .

    ok , i know it's not data call over GPRS , but i don't know how to establish data over GPRS
    i can get all informations from the provider (APN,IP,etc ) ,i have spical sim cards "2 sim data cards",it's used for data call only ,every one of them have an ip address .
    but what i need how to establish data call over GPRS step by step ?
    thanx for your replay

  11. #11
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    Default Re: how to establish data call ??

    According to your manual, you seem to have set it up OK for CSD.

    The number you are calling does ring? Is it a land phone line with an old modem?

    Does this modem answer the call?

    Does this modem have the same speed or is it auto speed set?

    Ioannis

  12. #12
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    Default Re: how to establish data call ??

    Quote Originally Posted by Ioannis View Post
    According to your manual, you seem to have set it up OK for CSD.

    The number you are calling does ring? Is it a land phone line with an old modem?

    Does this modem answer the call?

    Does this modem have the same speed or is it auto speed set?

    Ioannis
    no didn't ring , no it's a mobile phone
    i put 9600 for speed
    :sad:

  13. #13
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    Default Re: how to establish data call ??

    Do you have a land modem to make a test?

    If yes, call it and see if it rings.

    Then with the help of a terminal program send ATA to the modem and see if you manage to get a connection from the GSM call.

    Report results.

    Ioannis

  14. #14
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    Default Re: how to establish data call ??

    Quote Originally Posted by Ioannis View Post
    Do you have a land modem to make a test?

    If yes, call it and see if it rings.

    Then with the help of a terminal program send ATA to the modem and see if you manage to get a connection from the GSM call.

    Report results.

    Ioannis
    what is the land modem ?? u mean modem connect to telephone line ??

  15. #15
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    Default Re: how to establish data call ??

    Yes that is what i meant. The good old fashioned 28.8 or 33.6 or 56K modem. Maybe you have a laptop with such a device still on.

    Ioannis

  16. #16
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    Default Re: how to establish data call ??

    Quote Originally Posted by Ioannis View Post
    Yes that is what i meant. The good old fashioned 28.8 or 33.6 or 56K modem. Maybe you have a laptop with such a device still on.

    Ioannis
    ya i have one , on my laptop , i will test this if it's done or not
    thx alot

  17. #17
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    Default Re: how to establish data call ??

    i try to do this but it failed
    AT+FCLASS=0 ------------->data mode
    OK
    at+cbst=0,0,1 ---------> set the desired modulation & speed
    OK
    atd 022X1X4XY ------> this # my home telephone number, me put x & y cose it's my home NO CARRIER number

    i got again no carrier

  18. #18
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    Default Re: how to establish data call ??

    What are the parameters of the at+cbst command?

    Ioannis

  19. #19
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    Default Re: how to establish data call ??

    Quote Originally Posted by Ioannis View Post
    What are the parameters of the at+cbst command?

    Ioannis
    thx alot mr.Ioannis
    my mobile network that i connect to it did not support this service "data call on GSM !!!!
    now iam going to use GPRS over GSM network for send data
    if u have any information about this tell me plz

  20. #20
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    Default Re: how to establish data call ??

    Thar service i called DATA/FAX service (at least here I am) and is seperate service, charged according to your provider. You have to ask for activation and the provider will give you a second number for this on the same SIM card.

    About GPRS, it is the best solution, speed and cost considering, but there are a lot parameters to set and all these are dependant on your device. Sorry I do not have experience with Telit.

    Thats why I prefer something ready made for this purpose (see my above post #2).

    Ioannis

  21. #21
    Join Date
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    290

    Default Re: how to establish data call ??

    Quote Originally Posted by Ioannis View Post
    It is not that simple.

    You need to setup the GPRS modem according to its specific AT commands. Either on a terminal or through your PIC controller.

    Then you have to open a "channel" to a Static IP address since the Mobile Network ususally provides Dynamic IPs.

    Because I founded a bit difficult, I preffered the solution of a ready GPRS bridge to Serial: the WirelessCOM from Teltonika (www.teltonika.com).

    You only have to set up easily through a Terminal and then whenever you write even a single byte on the serial port, it establishes automatically a connection to the programmed IP and sends the data. Like Serial to serial communication.

    Ioannis
    Hi, it a relevant topic to what I am doing so I felt it would be right to have an opinion from someone on this topic. My project is to develop a tracking system. Everything is under control as far as AT commands are concerned and gprs modem is concerned (sim300 I am using).
    I have to guide our software developer to develop a server which can accept the data. I am not very expert when it comes to computers, electronics is mainly my field. I do not know how to explain him and what he needs to develop. I told him the process that through gprs my modem will get internet, and will connect to your (PC) server and send the data. I will need a port number, and a static IP.
    His question is that TCP/IP is different, gprs data packet is a different matter. He asks if I need socket programming which I dont have any clue about what he means.
    Can you please advise me, what in terms of server, needs to be developed in order to get the data from GPRS. Please mention details as to what software if any it should be made in like C, Java, Winsock etc, what data type should the software expect and any sort of relevant info which is helpful.

    The Bottom Line here is that what should be the relevant information I should give him so he can make something which can accept data from my modem through gprs connection. Just for info, my modem has built in TCP/IP stack (if that helps).
    Thanks


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