Newbie info-ppp over serial port


#1

Hello,

I’m using the Q2682 for GPRS interfacing it with a 32 bit controller running Linux. I understand that the modem has an inbuilt TCP/IP stack and runs openAT OS. My question is , since i am able to achieve a connection (start the stack, connect to bearer,send data,disconnect etc) via the supported AT commands, is there someway i can create a socket from my host (ie micro-controller) and map it to the GPRS connection? The idea is to provide a socket interface to the higher layers without exposing the transfer of data (between the MCU and modem) via serial communication

Is ppp a way to achieve this? From what i understand from the man pages,ppp is the protocol used for establishing Internet links over dial-up modems.Now isn’t this ‘establishment’ already done using the AT commands mentioned earlier?

Thanks.
Ravi


#2

Surely, Linux has a built-in TCP/IP stack and modem drivers? So why not just use them - and have the Q26 as just a “dumb” modem??


#3

Yes i figured out that is what ppp is used for. But the problem(?) is that if pppd is used, it will block the serial port to the modem forever(or alteast when pppd is running).I would have to use the other port (the modem has 2 ports) for the normal AT commands (Voice and SMS).Instead, if it were just using the WIPsoft software running on the modem, i could use the same uart for voice/sms and GPRS, all controlled through the relevant AT commands.Besides, i have to see if there’s a port of pppd and the tcpi/ip stack (in Linux) for my controller which is an ARM9 (I’m still checking that out…)

By the way, do you have an idea of how to map a socket (as detailed in my prevoius post) ?