fesp,
I have not used any of the SimCom modems but it should work fine with PPP. You don’t really need the GPRS Application kit, all it provides is support for text messaging and some sample programs. If you need text messaging its pretty simple just follow the AT command set for your modem.
Multiplexing is not supported by the PPP libraries, but you do get the source code so you can implement it yourself.
Here is the simplest GPRS sample that uses PPP to connect to the cellular network.
glued, thanks for your quick reply. As soon as my devkit comes in I’ll give it a try. This sample that you attached, where could I have find that myself?