Connecting to gprs Network


#1

Hello all, i am trying to connect to my operator GPRS but the modem allways gives me a NO CARRIER message, i don’t
know what to do coul somebody please help me?

Operator: Optimus
Country: Portugal
APN: internet

This is a list of my AT commands that i send from Hyperterminal:

at+cpin READY
at+cgclass=“CG”
at+cgdcont=1,“IP”,“internet”
at+cgact=1,1

Everything is fine, everything works however:

when i try to make a call like:
atd99**1#
it doesn’t work, it sends a lot of garbage to de screen and in the end it sends a NO CARRIER message.

Could somebody plllllllleeeeeaaaase help me, can it be broken???

Thank you in advance, i’m a noob in this, any help is welcome

Thank you in advance.


#2

Remember that GPRS is an IP network: the “garbage” that you see is PPP packets - and you need to respond with the appropriate PPP packets.

Because you don’t respond with the appropriate PPP packets, the “call” drops and you see NO CARRIER.

You need to connect something with an IP stack to the modem.

What exactly is it that you’re trying to achieve?


#3

Thank you for the reply, what i want to do is build a piece of hardware wich will communicate with an internet server,

then can you tell me where can i find a way to send data through this terminal, i think.

Basicaly what i whant to do is connect the GPRS modem to a terminal and send data through it.

Thank you

| Atonumous Hardware|<----------------Serial Connection--------->| WaveCom GPRS Modem |<-------------GPRS-------> INTERNET

this is a scheme a the communication.

Sorry bout the english, thank you.


#4

Do you really want to build your own hardware?

With Open-AT, your application runs on the Fastrack hardware - so you don’t need to build your own!

If you really must build your own hardware, you have 2 choices:

  1. The traditional approach: your hardware must contain the IP stack;
  2. Use WIPSoft to gain access to the the embedded stack within the Fastrack.

#5

I’ve installed Open-AT but i don’t really know where to start :confused:

Will WIPSoft make the communication transparent because what i need is only a way

to send bytes to a specific IP address!!!


#6

Ok i’ve been studying WIPSoft , i think its what i need… Can i count on you for any further questions? :slight_smile:

Thank you for the attention and your time, you have been a great help.


#7

Hi awneil, glad to see your message. I encountered the same problem as joaonl, unfortunately. Being involved in other works, the practice on the development kit is slow.

Anyway, my configuration is:
CPU: Q24PL001 (I don’t know if it is Q24PL001-A8P000, A8P007, A8QV00 or A8QV07. How can I know this from the label tag? )
Serial Link Speed: 115200 Bd

From the product catalogue, Q24PL001 has TCP/IP plug-in and Internet plug-in.

The starter kit is connected to the PC via serial comm. cable. Use MS HyperTerminal software to comm with the modem. The first objective is to establish GPRS connection and ping www.msn.com. I wish to see the ping procedure in HyperTerminal (possible???).
The following is the trial record:
at+cpin? +CPIN: READY
at+cgclass=“CG”
at+cgdcont=1,“IP”,“orangeinternet”,0,0
at+cgqreq=1,0,0,0,0,0
at+cgatt=1
at+cgact=1,1

Check the PDP address:
at+cgpaddr=1 => +CGPADDR: 1,“10.43.31.4”

So far so good. When i typed the enter data state command:
at+cgdata=1
What I saw on the screen was:
CONNECT 115200
~ }#À!}!}!} }6}!}$}%Ü}"}&} } } } }’}"}(}"}#}$À#&´~~ }#À!}!}!} }6}!}$}%Ü}"}&} } }
} }’}"}(}"}#}$À#&´~~ }#À!}!}!} }6}!}$}%Ü}"}&} } } } }’}"}(}"}#}$À#&´~~ }#À!}!}!
} }6}!}$}%Ü}"}&} } } } }’}"}(}"}#}$À#&´~~ }#À!}!}!} }6}!}$}%Ü}"}&} } } } }’}"}(}
“}#}$À#&´~~ }#À!}!}!} }6}!}$}%Ü}”}&} } } } }’}"}(}"}#}$À#&´~~ }#À!}!}!} }6}!}$}%
Ü}"}&} } } } }’}"}(}"}#}$À#&´~~ }#À!}!}!} }6}!}$}%Ü}"}&} } } } }’}"}(}"}#}$À#&´~
~ }#À!}!}!} }6}!}$}%Ü}"}&} } } } }’}"}(}"}#}$À#&´~~ }#À!}!}!} }6}!}$}%Ü}"}&} } }
} }’}"}(}"}#}$À#&´~
NO CARRIER

atd99**1#
has the same response.

From the response, can I say that the modem has established TCP/IP connection with the GPRS network???

According to your response to joaonl, I understand that the GPRS network had some communication with the modem using PPP. The modem directly sent these PPP packages to the HyperTerminal, and the HyperTerminal simply showed them on the screen, then I saw the “garbage” message. Am I right so far???
The HyperTerminal is not an application with IP stack, so it can’t response the modem with appropriate PPP packets. Am I right here?
Another software/application is needed to replace HyperTerminal and it should be able to response with appropriate PPP packets. But where should that software be put, in the PC like HyperTerminal, or in the modem? From your information, WIPSoft is possibly the easiest solution. Is it running inside the modem, rather than in the PC? How to load it into the modem? Sorry for the newbie question.

Because the Q24PL001 has TCP/IP and Internet plug-ins, why doesn’t it automatically convert the PPP packets and show the understandable message in the HyperTerminal, and turn the response from the HyperTerminal into PPP packets and send back to the GPRS network? So it is like a translator. It seems that I need read a lot about the modem to understand its structure before writing an embedded program for it.

I appologise if there is any confusion in my questions, and thank you and anyone who will provide his/her valuable comments.

–spencer


#8

No, it is not really possible.

Correct - it is not garbage; it is perfectly-formed PPP packets!

Yes.

Yes, that’s more-or-less it.

That depends upon your specific requirements!

Given that a PC already has a very capable IP stack built in, and is perfectly well able to establish network connections over any modem - whether PSTN, GSM, GPRS, or whatever - there seems very little point in duplicating this in the modem!

Not really.
If the modem is to be used with a PC, the easiest way is to simply set up a Network Connection in the PC that uses the modem.
Your operating system documentation will tell you how to do this!

Having the IP stack in the modem is really only of any benefit in an embedded application where in IP stack is not otherwise available.
On a PC, it is pointless.

Convert them to what?
The whole point of having a modem is that it uses PPP!

This is general dial-up networking stuff; it has nothing specifically to do with the Q24, or Wavecom, or GSM, or GPRS - exactly the same would happen with any modem!


#9

Thank you, awneil.

Yes, I agree with you. I am trying to install the modem in WinXP by adding new modem in the control panel. I installed the kit as a standard modem. The installation seemed successful, but I could not choose 115200bps which i used in the HyperTerminal. I chose COM1 and 9600bps. COM1 was used in HyperTerminal. But when i queried the modem in the diagnostics interface, it reported that the modem failed to response.

Can you see the reason? Thanks a lot.