In general you need a hardware interface of some kind to a PC or other "terminal device".
On a PC you would use an appropriate serial modem program to connect to the hardware interface as a serial port. You would then use the Hays/Rockwell modem attention (AT) comands to send the appropriate data to dial and then connect.
Having established the basic serial connection you might need to establish another protocol such as SLIP or PPP over the top of this. If this is the case you will need to have an appropriate "stack" in place to connect.
Before you go any further you need to find out what it is you are trying to do and the parameters of the service you are connecting to by that I mean the actuall destinatin modem you are dialing not the phone network you are connecting to.
If you are not sure I would look at using a Linux box not a windows box to get yourself up and running as the diagnostic tools available and the help on line generaly better.
---------- Post added at 23:04 ---------- Previous post was at 23:01 ----------
In general you need a hardware interface of some kind to a PC or other "terminal device".
On a PC you would use an appropriate serial modem program to connect to the hardware interface as a serial port. You would then use the Hays/Rockwell modem attention (AT) comands to send the appropriate data to dial and then connect.
Having established the basic serial connection you might need to establish another protocol such as SLIP or PPP over the top of this. If this is the case you will need to have an appropriate "stack" in place to connect.
Before you go any further you need to find out what it is you are trying to do and the parameters of the service you are connecting to by that I mean the actuall destinatin modem you are dialing not the phone network you are connecting to.
If you are not sure I would look at using a Linux box not a windows box to get yourself up and running as the diagnostic tools available and the help on line generaly better.
There are no data calls over GPRS, just TCP socket connections. I noticed, that Telit brings an embedded TCP/IP stack, so TCP connections can be achieved without involving much software overhead. The method is basically described in the GPRS command manual. Firstly, you have to know, what kind of TCP protocol you want to utilize, e.g. FTP, HTTP or a more low level generic port connection.what AT command i need to establish this data call ????
i need some example to establish this data call over GPRS
There are no data calls over GPRS, just TCP socket connections. I noticed, that Telit brings an embedded TCP/IP stack, so TCP connections can be achieved without involving much software overhead. The method is basically described in the GPRS command manual. Firstly, you have to know, what kind of TCP protocol you want to utilize, e.g. FTP, HTTP or a more low level generic port connection.
Please excuse, that I can't give any examples in this regard, because embedded TCP commands are completely vendor specific. Software utilizing it has to be adapted for each modem type. The other method would be to use only basic PPP over GPRS, that's supported by any GPRS modem and run a software PPP and TCP/IP stack on the processor. That's the way, most computers connect through a GPRS modem. It involves a considerable overhead, but may be reasonable, if a ready-to-use TCP/IP stack is available for a particular micro.
I fear, the intention isn't clear yet.
Basically any GSM modem can establish a CSD (circuit switched data) connection. The called party must have a data only or combined voice/data number and will be called by it. The connection has to be payed by the caller (unless covered by a flat rate). The transmission speed is slow, 9.6 or 14.4k maximum.
GPRS data connections go over dedicated access points (APN) offered by the network provider and are usually routed through the internet. Both peers must have internet access enabled by their internet provider and get either a temporary or permanent internet address. Routing of inbound connections is usually restricted with mobile internet connections, it may be e.g. limited to particular ports. If a permanent internet address has been assigned, it will be usually open to inbound connections, otherwise a permanen IP would be useless. An internet connection has to be payed according to volume or connection time (mostly covered by a flat rate) by both peers.
The original poster has been asking for a GPRS connection through APN, but then wanted to establish a "data call". I guess, that a TCP connection is meant, but it's not completely clear.
After setting the GPRS connection parameters with AT+cgdcont, the PPP connection is started with ATD*99.
On the PC server side, Windows (or any OS) will do this for you. On the mobile side, a PPP and TCP/IP stack must implemented on your microcontroller. When both peers are connected to the network, you can establish a TCP socket connection between them.
Instead of implenting a PPP and TCP/IP stack for the microcontroller, the EasyGPRS (embedded TCP stack) of the Telit modem can be used.
I already gave it in my first post. Try with the embedded TCP stack of the modem, as described in the EasyGPRS manual. As a disadvantage, the software is restricted to Telit modems, but it's small and simple. You can usually test the connection by "hacking" AT commands to a terminal.now what i can do ??? give me an advice ??
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