I have a client that has one of my embedded designs controlled via a wavecom modem over GSM. The embedded unit is controlled remotely via a uart interface and a dial-in, using hyperterminal on a PC as the control application; it also periodically reports its status over the uart interface using SMS to a mobile handset. The client now wants to evaluate GPRS since the deployment of the product may be growing.
Because of my lack of familiarity with networking software, what I can’t yet figure out from all the information that’s easily digestible, is which is going to be the cheapest development path (i.e. shortest time). If I read every piece of documentation going to figure all this out it would take a week of costs and the answer may be that Open AT is not it.
Do I implement a TCP/IP stack on my embedded unit and use PPP over the uart or do I develop apps for the OpenAT modem which just provide a serial ascii interface over the uart? I suspect it is trivial but I might have a lot of messing around to find out I’m wrong.
So how easy is it in OpenAT to provide a simple serial ascii output over the uart of say a ‘fasttrack supreme’? How much code do I have to create to provide the existing functionality that my client has, but using GPRS rather than a dial-in?
Eventually I’d like to port the embedded application on to the OpenAT modem and just provide the real world I/O interface as this would suit the client better, but that is too big a step to take at this stage.